scarf

Abstract

Suppresses the effects of thermal expansion. [Solution] The muffler comprises a shell member, an inner pipe, and a plate-shaped stay. The inner pipe extends from an opening in the shell member into the interior of the shell member. The stay comprises a first surface and a second surface facing each other in the thickness direction, and first and second joints provided at each end in the longitudinal direction. The first joint is joined to the outer circumferential surface of the inner pipe. The second joint is joined to the inner circumferential surface of the shell member. The longitudinal direction of the stay is inclined with respect to the extension direction of the inner pipe, and the second joint is located on the opening side of the first joint. The first surface of the stay faces the outer circumferential surface of the inner pipe.

Description

Technical Field

[0005]

[0001] The present disclosure relates to a muffler.

Background Art

[0002] As described in Patent Document 1, a muffler including a diffuser pipe and a catalyst cylinder disposed inside the diffuser pipe is known. The muffler has a plate-like stay joined to the outer peripheral surface of the catalyst cylinder and the inner peripheral surface of the diffuser pipe, and the catalyst cylinder is fixed to the diffuser pipe by the stay.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the muffler of Patent Document 1, if the end of the catalyst cylinder is joined to another member such as a diffuser pipe, when thermal elongation occurs in the catalyst cylinder, stress concentrates on the stay, and damage may occur at or around the stay.

[0005] In one aspect of the present disclosure, it is desirable to suppress the influence of thermal elongation.

Means for Solving the Problems

[0006] One aspect of the present disclosure is a muffler mounted on a vehicle, comprising a shell member, an opening edge, an inner pipe, and a stay. The shell member has an internal passage for exhaust gas from the engine. The opening edge surrounds an opening that connects the inside and outside of the shell member. The inner pipe is joined to the opening edge and is arranged to extend from the opening into the interior of the shell member. The stay is an elongated plate-shaped member extending in the longitudinal direction, having a first surface and a second surface facing each other in the thickness direction. The stay also comprises a first joint, a second joint, and a main body. The first joint is provided at the first end of the stay in the longitudinal direction and is joined to the outer circumferential surface of the inner pipe. The second joint is provided at the second end of the stay in the longitudinal direction and is joined to the inner circumferential surface of the shell member. The main body is provided between the first joint and the second joint and extends in the longitudinal direction. The stay is arranged so that its longitudinal direction is inclined with respect to the extension direction of the inner pipe. The second joint is located on the opening side of the first joint. The stay is positioned so that its first surface faces the outer surface of the inner pipe.

[0007] According to the above configuration, the first surface of the stay faces the outer surface of the inner pipe, so the stay can deform in accordance with the thermal expansion of the inner pipe. Furthermore, since the longitudinal direction of the stay is inclined in the direction of the extension of the inner pipe, the stay can be made longer, thereby suppressing the difference in length due to thermal expansion between the inner pipe and the stay. Therefore, damage to the stay due to thermal expansion can be suppressed, thereby suppressing the effects of thermal expansion.

[0008] In one aspect of this disclosure, the shell member is a pipe-shaped member extending in the direction of extension of the inner pipe, and may have a first opening and a second opening at both ends. The inner pipe may be joined to the opening edge surrounding the first opening of the shell member. The second joint may be located on the first opening side of the first joint.

[0009] The above configuration can suppress the effects of thermal expansion. In one aspect of this disclosure, the main body may extend in a substantially planar shape. According to the above configuration, the stay can be deformed appropriately in response to the thermal expansion of the inner pipe.

[0010] In one aspect of this disclosure, the main body may have a protrusion. The above configuration allows for improved rigidity of the stay. One aspect of the present disclosure may further include an orthogonal portion, which is located between the main body and the first joint and extends substantially planar in a direction substantially perpendicular to the extension direction of the section joined to the opening edge of the inner pipe.

[0011] According to the above configuration, the stay can be properly pressed by the jig during the muffler manufacturing process. In one aspect of this disclosure, the section of the inner pipe that includes an end located inside the shell member may be configured as an inclined section that slopes downward toward the end.

[0012] With the above configuration, condensed water accumulated inside the inner pipe can be effectively drained. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1A is a side view showing the interior of the shell member in the muffler of the first embodiment. Figure 1B is a perspective view of the stay of the first embodiment. Figure 1C is an explanatory diagram of the shell member of the first embodiment where resonance is occurring. [Figure 2] This is an explanatory diagram illustrating the process of press-fitting the inner pipe, to which the stay is joined, into the shell member during the manufacturing process of the muffler according to the first embodiment. [Figure 3] Figure 3A is an explanatory diagram illustrating the process of press-fitting the inner pipe, to which the stay is joined, into the shell member during the manufacturing process of the muffler of the second embodiment. Figure 3B is a transparent side view showing the inside of the shell member in the muffler of the third embodiment. [Modes for carrying out the invention]

[0014] Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the drawings. [1. First Embodiment] [(1) Overview] The muffler 1 of the first embodiment is mounted on a vehicle and is configured to allow the exhaust from the engine of the vehicle to flow down (see FIG. 1A). As an example, the muffler 1 may be configured as a small sub-muffler. The muffler 1 has a double-tube structure extending along an axis A, which is a virtual straight line, and includes a shell member 2 corresponding to an outer tube, an inner pipe 3 corresponding to an inner tube, and a stay 4.

[0015] [(2) Shell Member] The shell member 2 is, as an example, a cylindrical member extending straight along the axis A, and an exhaust flow path is provided inside (see FIG. 1A). Note that the cross section (hereinafter simply referred to as a cross section) of the shell member 2 perpendicular to the axis A is, as an example, circular, and as an example, the axis A passes through the center of the cross section of the shell member 2. The shell member 2 includes first and second openings 20, 21, first and second opening edges 20A, 21A, first and second tapered portions 22, 23, and a central portion 24.

[0016] <First and Second Openings> The first and second openings 20, 21 are circular openings located at the first end and the second end of the shell member 2, respectively. Note that, as an example, the first opening 20 forms an inlet for the exhaust of the muffler 1, and the second opening 21 forms an outlet for the exhaust of the muffler 1. However, it is not limited to this, and the second opening 21 may form an inlet for the exhaust of the muffler 1, and the first opening 20 may form an outlet for the exhaust of the muffler 1.

[0017] <First and Second Opening Edges> The first and second opening edges 20A, 21A are cylindrical portions surrounding the first and second openings 20, 21, respectively.

[0018] <First and Second Tapered Portions> The first and second tapered portions 22, 23 are respectively provided adjacent to the first and second opening edge portions 20A, 21A. The first and second tapered portions 22, 23 are inclined with respect to the axis A in a side view, and the cross-section becomes larger as they go toward the center in the direction of the axis A in the shell member 2.

[0019] <Central portion> The central portion 24 is a cylindrical portion extending along the axis A. The first and second tapered portions 22, 23 are respectively located at both ends of the central portion 24.

[0020] [(3) Inner pipe] The inner pipe 3 is, as an example, a cylindrical member extending straight along the axis A (see FIG. 1A). Also, the axis A passes through the center of the cross-section of the inner pipe 3.

[0021] The first end of the inner pipe 3 is inserted into the first opening edge portion 20A, and a portion near the first end on the outer peripheral surface 32 of the inner pipe 3 is joined (by welding, for example) to the first opening edge portion 20A. And the inner pipe 3 extends from the first opening edge portion 20A along the axis A into the interior of the shell member 2.

[0022] That is, the first opening 30 located at the first end of the inner pipe 3 is arranged to overlap with the first opening 20 of the shell member 2, and the second opening 31 located at the second end is arranged inside the shell member 2. For this reason, the exhaust gas flowing into the muffler 1 from the first opening 20 first passes through the inner pipe 3, and then flows out into the space between the inner pipe 3 and the shell member 2. And the exhaust gas flows out from the second opening 31 to the outside of the muffler 1.

[0023] [(4) Stay] [[ID=2|6]]The stay 4 is provided to support the inner pipe 3, and is an elongated plate-like member extending in the longitudinal direction L and has first and second surfaces 45, 46 facing each other in the thickness direction (see FIGS. 1A, 1B). The stay 4 includes a main body portion 40 and first and second joining portions 41, 42.

[0024] <Main body portion> The main body portion 40 is an elongated, plate-like part extending along the longitudinal direction L. For example, the main body portion 40 is substantially planar and has a substantially rectangular shape extending along the longitudinal direction L. However, it is not limited to this, and the shape of the main body portion 40 can be determined as appropriate. Specifically, for example, the main body portion 40 may be bent or curved, or it may be bent or curved at multiple points along the longitudinal direction L.

[0025] Furthermore, the main body portion 40 is provided with a protrusion 43 that projects toward the second surface 46. For example, the protrusion 43 is located approximately in the center of the width direction of the main body portion 40 and extends along the longitudinal direction L. Of course, the position and shape of the protrusion 43 are not limited to this and can be determined as appropriate, and the main body portion 40 may be provided with multiple protrusions.

[0026] Furthermore, a positioning hole 44 is provided between the protrusion 43 and the second joint 42 of the main body 40, and the hole penetrates the main body 40. The positioning hole 44 is used, for example, to position the stay 4 when joining it to the inner pipe 3 during the manufacturing process of the muffler 1.

[0027] <First and second joints> The first and second joints 41 and 42 are plate-shaped portions provided at the first and second ends of the stay 4 in the longitudinal direction L, respectively. In other words, the first and second joints 41 and 42 are adjacent to both ends of the main body 40 in the longitudinal direction L, respectively. For example, the first and second joints 41 and 42 are roughly rectangular. Furthermore, the first and second joints 41 and 42 extend from both ends of the main body 40 in the longitudinal direction L in a bending manner, and the angles d1 and d2 at which the first and second joints 41 and 42 intersect with the main body 40 are obtuse angles. The first and second joints 41 and 42 are joined (for example, welded) to the outer circumferential surface 32 of the inner pipe 3 and the inner circumferential surface 25 of the shell member 2, respectively.

[0028] <Slanting of the stay> The longitudinal direction L of the stay 4 and the main body 40 is inclined with respect to the axis A, in other words, the extension direction of the inner pipe 3 and the shell member 2. That is, the second joint 42 is located on the first opening 30 side of the inner pipe 3 than the main body 40, and the first joint 41 is located on the second opening 21 side of the main body 40. Also, the second joint 42 is located on the first opening 30 side of the first joint 41.

[0029] <Pages 1 and 2> The first and second surfaces 45 and 46 of the stay 4 face the outer circumferential surface 32 of the inner pipe 3 and the inner circumferential surface 25 of the shell member 2, respectively. Also, as an example, when the stay 4 is viewed in the thickness direction, the stay 4 extends in the direction of axis A. However, it is not limited to this, and when viewed in the thickness direction, the stay 4 may extend in a direction inclined with respect to axis A.

[0030] [(5) Position of the stay] The position of the stay 4 can be determined as appropriate. Specifically, for example, the stay 4 may be provided closer to the first opening 20 than to the center in the direction of axis A in the inner pipe 3. This reduces the stress applied to the stay 4 when thermal expansion occurs in the inner pipe 3, compared to the case where the stay 4 is provided closer to the second opening 21 than to the center, thereby further suppressing the effects of thermal expansion.

[0031] Furthermore, for example, the stay 4 may be provided closer to the second opening 21 than to the center of the inner pipe 3. This suppresses resonance in the inner pipe 3 compared to the case where the stay 4 is provided closer to the first opening 20 than to the center.

[0032] In addition, the positions of the first and second joints 41 and 42 of the stay 4 may be determined in order to suppress vibrations in the inner pipe 3 or the shell member 2. That is, as shown in Figure 1C, the second joint portion 42 of the stay 4 may be provided at any of the antinodes 2A to 2C in the first to third mode resonances occurring in the central portion 24 of the shell member 2. Of course, multiple second joint portions 42 of stays 4 may be provided at multiple antinodes 2A to 2C in the first to third mode resonances. In addition, the first joint portion 41 of the stay 4 may be provided at the antinodes of the resonances occurring in the inner pipe 3.

[0033] [(6) Number of stays] In Figure 1A, as an example, the muffler 1 is provided with one stay 4, but the number of stays 4 can be determined as appropriate. Also, if the muffler 1 is provided with multiple stays 4, as shown in Figure 2, each stay 4 may be provided at different positions in the circumferential direction around axis A. In other words, each stay 4 may be arranged so as not to overlap when viewing the inner pipe 3 in the direction of axis A.

[0034] Here, the manufacturing process for muffler 1, as an example, includes the following steps. (1) The first joint portions 41 of multiple stays 4 are welded to the inner pipe 3. (2) An intermediate shell member 2A is formed at the first end, which has a first opening edge 20A and a first tapered portion 22, and at the second end, which has a second opening edge 21A and an opening 26 instead of the second tapered portion 23.

[0035] (3) The inner pipe 3, to which multiple stays 4 are welded, is press-fitted into the interior of the intermediate shell member 2A through the opening 26. (4) The vicinity of the first end of the inner pipe 3 is welded to the first opening edge 20A of the shell member 2, and the second joint 42 of the stay 4 is welded to the central part 24 of the shell member 2.

[0036] (5) A second opening edge portion 21A and a second tapered portion 23 are formed at the second end of the intermediate shell member 2A. In step (3), the inner pipe 3 is press-fitted into the shell member 2 with the second joint portions 42 of each stay 4 welded to the inner pipe 3 in contact with the inner circumferential surface 25 of the shell member 2. At this time, in order to suppress damage to each stay 4, it is desirable to press-fit the inner pipe 3 into the shell member 2 by pressing the edges surrounding the second opening 31 of the inner pipe 3 against each stay 4 using a press-fitting jig.

[0037] In contrast, by positioning each stay 4 at different locations in the circumferential direction, it becomes possible to press all stays 4 with the press-fitting jig. This makes it possible to perform the press-fitting in step (3) smoothly.

[0038] [2. Second Embodiment] The muffler 1 of the second embodiment differs in the configuration of the stay 4. The differences between the muffler 1 of the second embodiment and the first embodiment will be described below.

[0039] In other words, in the second embodiment, the stay 4 further comprises an orthogonal portion 47 (see Figure 3A). The orthogonal portion 47 is located between the main body portion 40 and the first joint portion 41 and is a plate-shaped portion that extends substantially planar in a direction substantially perpendicular to the axis A. As an example, the orthogonal portion 47 extends from the first end to the second end in the width direction of the stay 4.

[0040] Then, in step (3) described above in the manufacturing process of the muffler 1 of the second embodiment, a press-fit jig 5 having a configuration corresponding to the stay 4 of the second embodiment is used. That is, the press-fit jig 5 has a contact surface 50 that spreads out in a substantially planar shape, and the contact surface 50 is oriented substantially perpendicular to the axis A when pressing the inner pipe 3, etc. Then, the press-fit jig 5 presses the inner pipe 3 and the stay 4 with the contact surface 50 in contact with the perpendicular portion 47.

[0041] [3. Third Embodiment] The muffler 1 of the third embodiment differs in the configuration of the inner pipe 3. The differences between the muffler 1 of the third embodiment and the first embodiment will be described below.

[0042] In other words, in the third embodiment, the inner pipe 3 has a normal section 33 including the first opening 30 and an inclined section 34 adjacent to the normal section 33 and including the second opening 31 (see Figure 3B).

[0043] The normal section 33 extends along axis A, as in the first embodiment, and axis A passes through the center of the cross-section of the normal section 33. On the other hand, the inclined section 34 extends in a direction that is inclined with respect to axis A. While the inclined section 34 may, for example, extend in a straight line, it is not limited to this and may also be curved.

[0044] The muffler 1 of the third embodiment is mounted on the vehicle such that the inclined section 34 is inclined downward as it approaches the second opening 31. [4. Effects] (1) In a muffler having a double-pipe structure as in the above embodiment, a technique is known in which the inner pipe is supported by a separator, which is a plate-shaped member that extends in a direction substantially perpendicular to the axis and is provided so as to surround the inner pipe. In addition, a technique is known in which the inner pipe is supported by a plurality of short stays that connect the inner pipe and the shell member. When these techniques are employed, if thermal expansion occurs in the inner pipe, stress will concentrate at the joint between the inner pipe and the shell member, or at the joint between the inner pipe and the separator or stay, and there is a risk that these joints will be damaged.

[0045] While the above problem can be solved by not using such separators or stays, on the other hand, there is a risk of damage due to vibrations caused by exhaust pulsation, or resonance in the inner pipe, resulting in damage or noise.

[0046] In addition, it is conceivable to suppress stress concentration at the joint between the inner pipe and the shell member by providing a buffer material (for example, wire mesh) at the joint. However, providing a buffer material increases manufacturing costs. Furthermore, there is a risk that condensed water accumulated inside the shell member may pass through the buffer material and flow into the exhaust pipe connected to the muffler, potentially blocking the exhaust pipe or causing the condensed water to freeze inside the exhaust pipe, preventing the engine from starting.

[0047] In contrast, according to the above embodiment, the first surface 45 of the stay 4 faces the outer circumferential surface 32 of the inner pipe 3, and the second surface 46 faces the inner circumferential surface 25 of the shell member 2, so that the stay 4 can deform in accordance with the thermal expansion of the inner pipe 3. More specifically, for example, the angles d1 and d2 at which the first and second joints 41 and 42 intersect with the main body 40 change in accordance with the thermal expansion of the inner pipe 3. Also, since the longitudinal direction L of the stay 4 is inclined with respect to the axis A, the stay 4 can be made longer, thereby suppressing the difference in length due to thermal expansion between the inner pipe 3 and the stay 4. Therefore, damage to the stay 4 due to thermal expansion can be suppressed, thereby suppressing the effects of thermal expansion.

[0048] Furthermore, the stay 4 is expected to occupy a smaller portion of the cross-sectional area of ​​the shell member 2 compared to the separator. Therefore, the internal space of the shell member 2 can be used more effectively. Furthermore, since stay 4 has a simpler structure compared to the separator, it is easier to manufacture and its quality can be stabilized.

[0049] Furthermore, even when multiple stays 4 are provided, multiple stays 4 can be welded to the inner pipe 3 in a single welding step, thus streamlining the welding process. Furthermore, by determining the positions of the first and second joints 41 and 42 of the stay 4 while considering the resonance characteristics of the shell member 2 and the inner pipe 3, vibration and noise can be effectively suppressed.

[0050] (2) Furthermore, the main body portion 40 of the stay 4 spreads out in a substantially flat shape. Therefore, the stay 4 can be deformed well in response to the thermal expansion of the inner pipe 3. (3) Furthermore, the main body portion 40 of the stay 4 has a protrusion 43. This improves the rigidity of the stay 4.

[0051] (4) Furthermore, the stay 4 of the muffler 1 in the second embodiment has an orthogonal portion 47 that extends in a substantially planar direction substantially perpendicular to the axis A. Therefore, in step (3) of the manufacturing process of the muffler 1, the orthogonal portion 47 can be pressed into the intermediate shell member 2A by pressing the contact surface 50 of the press-fitting jig 5 which extends in a substantially planar direction. Therefore, the stay 4 can be pressed well by the press-fitting jig 5 in the manufacturing process of the muffler 1.

[0052] (5) Furthermore, the section of the inner pipe 3 in the third embodiment that includes the second opening 31 is configured as an inclined section 34 that slopes downward as it approaches the second opening 31. As a result, condensed water accumulated inside the inner pipe 3 can be discharged effectively, preventing malfunctions that may occur due to condensed water remaining inside the exhaust pipe or engine.

[0053] [5. Other Embodiments] (1) In the above embodiment, the muffler 1 has a double-pipe structure, and the shell member 2 and the inner pipe 3 have a straight cylindrical shape. However, it is not limited to this, and for example, both or one of the shell member and the inner pipe may have a curved shape. In such a case, it may be difficult to support the inner pipe with the separator described above, but when the stay 4 is used, the inner pipe can be supported well.

[0054] Furthermore, the shell member may not be cylindrical, but rather a cylindrical member with a substantially elliptical or substantially rectangular cross-section, for example. In this case, the inner pipe may be provided extending from an opening on the outer circumferential surface of the shell member, and the inner pipe may be supported by a stay inclined with respect to the axis of the inner pipe, in the same manner as in the above embodiment.

[0055] (2) Multiple functions of one component in the above embodiment may be realized by multiple components, or one function of one component may be realized by multiple components. Also, multiple functions of multiple components may be realized by one component, or one function realized by multiple components may be realized by one component. Furthermore, some of the configurations of the above embodiment may be omitted. Also, at least some of the configurations of the above embodiment may be added to or replaced with the configurations of other above embodiments.

[0056] [6. The technical concept disclosed herein] [Item 1] A muffler mounted on a vehicle, A shell member having an exhaust passage from the engine inside, An opening edge surrounding the opening that connects the inside and outside of the shell member, An inner pipe is joined to the opening edge and is arranged to extend from the opening into the interior of the shell member, A stay is a long, slender plate-shaped member extending in the longitudinal direction, having a first surface and a second surface facing each other in the thickness direction. The aforementioned stay is, A first joint portion is provided at the first longitudinal end of the stay and is joined to the outer circumferential surface of the inner pipe, A second joint portion is provided at the second end of the stay in the longitudinal direction and is joined to the inner circumferential surface of the shell member, It comprises a main body portion provided between the first joint portion and the second joint portion and extending in the longitudinal direction, The stay is arranged such that its longitudinal direction is inclined with respect to the extension direction of the inner pipe. The second joint is located on the opening side of the first joint, The stay is positioned such that the first surface faces the outer surface of the inner pipe. scarf.

[0057] [Item 2] The muffler described in item 1, The shell member is a pipe-shaped member extending in the extension direction of the inner pipe, and has a first opening and a second opening at both ends. The inner pipe is joined to the opening edge of the shell member that surrounds the first opening. The second joint is located on the first opening side of the first joint. scarf.

[0058] [Item 3] A muffler as described in item 1 or item 2, The main body portion spreads out in a substantially planar shape. scarf.

[0059] [Item 4] A muffler described in any one of items 1 through 3, The main body portion has a protruding portion. scarf.

[0060] [Item 5] A muffler that is described in any one of items 1 through 4, The orthogonal portion is located between the main body and the first joint and extends substantially planar in a direction substantially perpendicular to the extension direction of the section joined to the opening edge of the inner pipe. scarf.

[0061] [Item 6] A muffler that is described in any one of items 1 through 5, The section of the inner pipe that includes the end located inside the shell member is configured as an inclined section that slopes downward as it approaches the end. scarf. [Explanation of Symbols]

[0062] A...axis, 1...muffler, 2...shell member, 2A...intermediate shell member, 20...first opening, 20A...edge of the first opening, 21...second opening, 21A...edge of the second opening, 22...first tapered section, 23...second tapered section, 24...center section, 25...inner circumferential surface, 26...opening, 3...inner pipe, 30...first opening, 31...second opening, 32...outer circumferential surface, 33...normal section, 34...inclined section, 4...stay, 40...main body section, 41...first joint section, 42...second joint section, 43...protrusion, 44...positioning hole, 45...first surface, 46...second surface, 47...orthogonal section, L...longitudinal direction, 5...press-fitting jig.

Claims

1. A muffler mounted on a vehicle, A shell member having an exhaust passage from the engine inside, An opening edge surrounding the opening that connects the inside and outside of the shell member, An inner pipe is joined to the opening edge and is arranged to extend from the opening into the interior of the shell member, A stay is a long, slender plate-shaped member extending in the longitudinal direction, having a first surface and a second surface facing each other in the thickness direction. The aforementioned stay is, A first joint portion is provided at the first longitudinal end of the stay and is joined to the outer circumferential surface of the inner pipe, A second joint portion is provided at the second end of the stay in the longitudinal direction and is joined to the inner circumferential surface of the shell member, It comprises a main body portion provided between the first joint portion and the second joint portion and extending in the longitudinal direction, The stay is arranged such that its longitudinal direction is inclined with respect to the extension direction of the inner pipe. The second joint is located on the opening side of the first joint, The stay is positioned such that its first surface faces the outer surface of the inner pipe. scarf.

2. The muffler according to claim 1, The shell member is a pipe-shaped member extending in the extension direction of the inner pipe, and has a first opening and a second opening at both ends. The inner pipe is joined to the opening edge of the shell member that surrounds the first opening. The second joint is located on the first opening side of the first joint. scarf.

3. A muffler according to claim 1 or claim 2, The main body portion spreads out in a substantially planar shape. scarf.

4. A muffler according to claim 1 or claim 2, The main body portion has a protruding portion. scarf.

5. A muffler according to claim 1 or claim 2, The orthogonal portion is located between the main body and the first joint and extends substantially in a planar manner in a direction substantially perpendicular to the extension direction of the section joined to the opening edge of the inner pipe. scarf.

6. A muffler according to claim 1 or claim 2, The section of the inner pipe that includes the end located inside the shell member is configured as an inclined section that slopes downward as it approaches the end. scarf.

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