scarf

Abstract

This provides technology to improve the vibration intensity of mufflers. [Solution] The muffler comprises an outer shell member, N separators (N is a positive number satisfying 2 ≤ N), a first pipe, and a second pipe. A first communication opening is formed in the first closed portion of the outer shell member. A second communication opening is formed in the second closed portion of the outer shell member. First through holes are formed in the 1st to xth separators (x is a positive number satisfying 2 ≤ x ≤ N) from the first closed portion side. Second through holes are formed in the 1st to yth separators (y is a positive number satisfying 1 ≤ y ≤ N and N+1 ≤ x+y) from the second closed portion side. The first pipe is inserted through the first communication opening and each of the first through holes, joined to the first closed portion and the 1st separator from the first closed portion side, and slidably held by the 2nd to xth separators from the first closed portion side. The second pipe is inserted through the second communication opening and each of the second through holes, and joined to at least the second closed portion.

Description

Technical Field

[0001] The present disclosure relates to a muffler provided in an exhaust gas flow path from an internal combustion engine.

Background Art

[0002] For example, Patent Document 1 describes a muffler provided in an exhaust gas flow path from an internal combustion engine. The muffler described in Patent Document 1 includes an outer shell member, a plurality of separators, and two pipes. The outer shell member has a cylindrical outer peripheral portion surrounding an internal space and two end plates closing the openings at both ends of the outer peripheral portion. Through holes are respectively formed in the two end plates. The plurality of separators are members for partitioning the internal space. Two through holes are respectively formed in the plurality of separators. The two pipes are respectively inserted through the through holes of one of the end plates and the through holes of each separator.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the muffler described in Patent Document 1, each pipe is joined to an end plate, while being held slidably without being joined to each separator. However, as a result of intensive studies by the present inventor, it has been found that in the muffler described in Patent Document 1, when vibration occurs in the pipe, stress tends to concentrate at the joint between the pipe and the end plate. From the viewpoint of the vibration strength of the muffler, it is desirable that stress does not easily concentrate on a specific portion in the muffler when vibration occurs.

[0005] One aspect of the present disclosure provides a technique for improving the vibration strength of a muffler.

Means for Solving the Problems

[0006] One aspect of the present disclosure is a muffler provided in the exhaust gas passage of an internal combustion engine, comprising an outer shell member, N separators, a first pipe, and a second pipe, where N is a positive number satisfying 2 ≤ N. The outer shell member has a circumferential wall portion, a first closing portion, and a second closing portion. The circumferential wall portion is cylindrical. The circumferential wall portion surrounds an internal space. The first closing portion and the second closing portion each close two openings in the axial direction of the circumferential wall portion. The N separators are plate-shaped members that partition the internal space. The N separators are arranged in the axial direction of the circumferential wall portion. The first pipe and the second pipe are cylindrical members whose ends are positioned within the internal space. The first closing portion has a first communication opening that connects the internal space to the outside of the outer shell member. The second closing portion has a second communication opening that connects the internal space to the outside. Of the N separators, the first to x separators from the first closure side have first through-holes that penetrate them. x is a positive number satisfying 2 ≤ x ≤ N. Of the N separators, the first to y separators from the second closure side have second through-holes that penetrate them. y is a positive number satisfying 1 ≤ y ≤ N and N+1 ≤ x+y. The first pipe is inserted through the first communication port and the first through-holes of the first to x separators from the first closure side. The first pipe is joined to the first closure and the first separator from the first closure side. The first pipe is slidably held by the second to x separators from the first closure side. The second pipe is inserted through the second communication port and the second through-holes of the first to y separators from the second closure side. The second pipe is joined to at least the second closure.

[0007] This configuration can improve the vibration intensity of the muffler.

[0008] In one aspect of this disclosure, y may be a positive number satisfying 2 ≤ y ≤ N and N+1 ≤ x + y. The second pipe may be joined to the second closure and the first separator from the second closure side. The second pipe may be slidably held by the second to yth separators from the second closure side.

[0009] This configuration allows for further improvement of the muffler's vibration intensity.

[0010] In one aspect of this disclosure, y may be a positive number satisfying y=N. The first separator from the first closure side may have at least one rising portion and at least one easing portion. The rising portion rises from the edge of the second through hole. At least one easing portion is adjacent to at least one rising portion. At least one easing portion is lower in height than at least one rising portion. At least one easing portion may include a proximity easing portion. The proximity easing portion is a easing portion arranged in a range that includes the position at the edge of the second through hole where the distance from the first through hole is minimized.

[0011] This configuration can improve the heat resistance of the muffler.

[0012] In one aspect of this disclosure, at least one relaxation section may include a plurality of relaxation sections, including adjacent relaxation sections. The plurality of relaxation sections may be arranged at equal intervals along the edge of the second through hole.

[0013] This configuration makes it possible to prevent the holding force of at least one rising portion on the second pipe from being reduced too much. [Brief explanation of the drawing]

[0014] [Figure 1] This is a cross-sectional view of the muffler according to the first embodiment. [Figure 2] This is a perspective view of the first separator of the embodiment. [Figure 3] This is a plan view of the first separator of the embodiment. [Figure 4] FIG. 4A is a schematic cross-sectional view showing a state where an inlet pipe inserted into the first separator has thermally expanded. FIG. 4B is a schematic cross-sectional view showing a state where an outlet pipe inserted into the first separator has thermally expanded. [Figure 5] Perspective view of the separator of the modified example. [Figure 6] Plan view of the separator of the modified example. [Figure 7] Cross-sectional view of the muffler of the second embodiment. [Figure 8] Cross-sectional view of the muffler of the third embodiment. [Embodiments for Carrying Out the Invention]

[0015] Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the drawings.

[0016] [1. First Embodiment] [1-1. Configuration] The muffler 1 shown in FIG. 1 is mounted on a vehicle. The muffler 1 is provided in the flow path of the exhaust gas G from the internal combustion engine of the vehicle. The muffler 1 is configured to reduce the exhaust sound of the vehicle. The muffler 1 includes an outer shell member 2, a first separator 3A, a second separator 3B, an inlet pipe 4, and an outlet pipe 5.

[0017] The outer shell member 2 is a member that constitutes the outer surface of the muffler 1. A space is formed inside the outer shell member 2. Hereinafter, the space inside the outer shell member 2 will be referred to as the internal space S. The outer shell member 2 has a shell 21, a first end plate 22, and a second end plate 23.

[0018] The shell 21 is a cylindrical part. The shell 21 surrounds the internal space S. The central axis of the shell 21 is linear. In FIG. 1, the axial direction of the shell 21 coincides with the left-right direction. The outer and inner shapes of the cross-section perpendicular to the axial direction of the shell 21 are elliptical. The dimensions along the outer periphery of the shell 21 are constant in the axial direction of the shell 21.

[0019] The shell 21 has a first end portion 211 and a second end portion 212. The first end portion 211 is one end portion in the axial direction of the shell 21. The second end portion 212 is the other end portion (that is, the end portion on the side opposite to the first end portion 211 side) in the axial direction of the shell 21. The first end portion 211 and the second end portion 212 each form an opening.

[0020] The first end plate 22 and the second end plate 23 are plate-shaped members. The outer shapes of the first end plate 22 and the second end plate 23 viewed from their plate thickness directions are elliptical. The first end plate 22 closes the opening formed by the first end portion 211. In other words, the first end plate 22 closes one opening in the axial direction of the shell 21. The second end plate 23 closes the opening formed by the second end portion 212. In other words, the second end plate 23 closes the other opening (that is, the opening on the side opposite to the first end plate 22 side) in the axial direction of the shell 21.

[0021] A first communication port 221 is formed in the first end plate 22. A second communication port 231 is formed in the second end plate 23. The first communication port 221 and the second communication port 231 are openings that communicate the internal space S with the outside of the outer shell member 2. An inlet pipe 4 is inserted into the first communication port 221. The shape of the edge of the first communication port 221 is a shape corresponding to the outer shape of the inlet pipe 4 (circular shape in this embodiment). An outlet pipe 5 is inserted into the second communication port 231. The shape of the edge of the second communication port 231 is a shape corresponding to the outer shape of the outlet pipe 5 (circular shape in this embodiment). In the state where the first end plate 22 and the second end plate 23 are respectively arranged at the first end portion 211 and the second end portion 212 of the shell 21, the first communication port 221 and the second communication port 231 do not overlap each other when viewed from the axial direction of the shell 21.

[0022] Since the first separator 3A and the second separator 3B have generally similar configurations, only the first separator 3A is shown in Figures 2 and 3. The first separator 3A and the second separator 3B are plate-shaped members. The outer shape of the first separator 3A and the second separator 3B, when viewed from the thickness direction of their own plates, corresponds to the inner shape of the shell 21. In this embodiment, the outer shape is generally elliptical.

[0023] As shown in Figure 1, the first separator 3A and the second separator 3B are arranged within the internal space S. The first separator 3A and the second separator 3B are aligned in the axial direction of the shell 21. The thickness direction of each of the first separator 3A and the second separator 3B coincides with the axial direction of the shell 21.

[0024] Within the internal space S, the first separator 3A is positioned closer to the first end plate 22 than the second separator 3B. That is, the first separator 3A is the first separator from the first end plate 22 side. The second separator 3B is the first separator from the second end plate 23 side. The first separator 3A faces the first end plate 22 with a gap between them. The second separator 3B faces the second end plate 23 with a gap between them. The first separator 3A and the second separator 3B face each other with a gap between them.

[0025] The first separator 3A and the second separator 3B divide the internal space S. Specifically, the first separator 3A and the second separator 3B divide the internal space S into three areas: the first area X1, the second area X2, and the third area X3. The first area X1 is the area on the first end plate 22 side of the first separator 3A. The second area X2 is the area between the first separator 3A and the second separator 3B. The third area X3 is the area on the second end plate 23 side of the second separator 3B.

[0026] Both the first separator 3A and the second separator 3B have a main body portion 31, an outer edge portion 32, a full-circumference rising portion 33, a plurality of partial rising portions 34, and a plurality of relaxation portions 35, as shown in Figures 2 and 3. The number of partial rising portions 34 and the number of relaxation portions 35 are the same, and in this embodiment, there are four of each.

[0027] The main body portion 31 is a plate-shaped part. For example, the main body portion 31 is flat. The outer shape of the main body portion 31, when viewed from the thickness direction, corresponds to the inner shape of the shell 21. In this embodiment, the outer shape is generally elliptical. The main body portion 31 has a fixing hole 311, a sliding hole 312, and a plurality of communication holes 313.

[0028] The fixing hole 311 and the sliding hole 312 are through holes that penetrate the main body 31 in the thickness direction. The inlet pipe 4 or the outlet pipe 5 is inserted (for example, press-fitted) through the fixing hole 311 and the sliding hole 312. Specifically, as shown in Figure 1, the inlet pipe 4 is inserted through the fixing hole 311 of the first separator 3A and the sliding hole 312 of the second separator 3B. The shape of the edges of the fixing hole 311 of the first separator 3A and the sliding hole 312 of the second separator 3B corresponds to the shape of the outer shape of the inlet pipe 4 (circular in this embodiment). The outlet pipe 5 is inserted through the sliding hole 312 of the first separator 3A and the fixing hole 311 of the second separator 3B. The shape of the edges of the sliding hole 312 of the first separator 3A and the fixing hole 311 of the second separator 3B corresponds to the shape of the outer shape of the outlet pipe 5 (circular in this embodiment).

[0029] As shown in Figures 2 and 3, the multiple communication holes 313 are through holes that penetrate the main body 31 in the thickness direction. The size of each of the multiple communication holes 313 is smaller than the fixing holes 311 and the sliding holes 312. The multiple communication holes 313 connect adjacent regions X1 to X3 with the first separator 3A or the second separator 3B in between. Specifically, the multiple communication holes 313 of the first separator 3A connect the first region X1 and the second region X2. The multiple communication holes 313 of the second separator 3B connect the second region X2 and the third region X3.

[0030] The outer edge portion 32 is a cylindrical part provided at the outer peripheral end of the main body portion 31. In other words, the outer edge portion 32 is a part that protrudes from the entire circumference of the outer peripheral end of the main body portion 31 in the thickness direction of the main body portion 31. When the first separator 3A and the second separator 3B are arranged in the internal space S, the outer edge portion 32 is in contact with the inner surface of the shell 21 over almost its entire circumference. The outer edge portion 32 is joined to the shell 21, for example, by welding.

[0031] The circumferential rising portion 33 is the part that rises from the entire circumference of the edge of the fixing hole 311. In other words, the circumferential rising portion 33 is cylindrical. The circumferential rising portion 33 rises on the same side as the outer edge portion 32 relative to the main body portion 31. The circumferential rising portion 33 contacts the inlet pipe 4 or outlet pipe 5 that is inserted through the fixing hole 311. The circumferential rising portion 33 is formed, for example, by burring.

[0032] The multiple partial rise portions 34 are parts that rise from a portion of the edge of the sliding hole 312. The multiple partial rise portions 34 are plate-shaped. The multiple partial rise portions 34 rise on the same side as the outer edge portion 32 relative to the main body portion 31, that is, on the same side as the full-circumference rise portion 33. The multiple partial rise portions 34 are arranged at equal intervals along the edge of the sliding hole 312. The multiple partial rise portions 34 are in contact with the inlet pipe 4 or outlet pipe 5 that is inserted into the sliding hole 312.

[0033] The multiple relaxation portions 35 are areas adjacent to the partial rise portions 34 along the edge of the sliding hole 312. In this embodiment, where there are multiple partial rise portions 34, the multiple relaxation portions 35 can also be described as areas sandwiched between the partial rise portions 34 along the edge of the sliding hole 312.

[0034] The heights of the multiple relief sections 35 are lower than the heights of the multiple partial rise sections 34. The height of the partial rise section 34 or relief section 35 refers to the dimension of the partial rise section 34 or relief section 35 in the thickness direction of the main body section 31. In this embodiment, the height of the multiple relief sections 35 is 0. That is, the multiple relief sections 35 in this embodiment do not rise at all from the edge of the sliding hole 312.

[0035] Figures 2 and 3 show the position on the edge of the fixed hole 311 where the distance between it and the sliding hole 312 is minimized, which is shown as the fixed-side proximity position P1. Similarly, the position on the edge of the sliding hole 312 where the distance between it and the fixed hole 311 is minimized, which is shown as the sliding-side proximity position P2. Hereafter, the fixed-side proximity position P1 and the sliding-side proximity position P2 will simply be referred to as proximity positions P1 and P2. The line segment connecting proximity positions P1 and P2 in a straight line will be called the shortest line segment L.

[0036] It is preferable that the multiple relief portions 35 are arranged in a range that includes at least the proximity position P2 on the edge of the sliding hole 312. In other words, it is preferable that the multiple relief portions 35 include proximity relief portions 35a. The proximity relief portions 35a are relief portions 35 arranged in a range that includes the proximity position P2 on the edge of the sliding hole 312.

[0037] The method for forming the partial rise portion 34 and the relaxation portion 35 in the first separator 3A and the second separator 3B is not particularly limited. For example, a full-circumference rise portion rising from the entire circumference along the edge of the sliding hole 312 may be formed by burring, and then a part of this full-circumference rise portion in the circumferential direction may be cut out to form the partial rise portion 34 and the relaxation portion 35.

[0038] Returning to Figure 1, the first separator 3A is positioned in the internal space S with its outer edge 32 projecting toward the first end plate 22 relative to the main body 31. The second separator 3B is positioned in the internal space S with its outer edge 32 projecting toward the second end plate 23 relative to the main body 31. Viewed from the axial direction of the shell 21, the fixing hole 311 of the first separator 3A overlaps with the sliding hole 312 of the second separator 3B. Also, viewed from the axial direction of the shell 21, the fixing hole 311 of the first separator 3A overlaps with the first communication opening 221. Viewed from the axial direction of the shell 21, the fixing hole 311 of the second separator 3B overlaps with the sliding hole 312 of the first separator 3A. Also, viewed from the axial direction of the shell 21, the fixing hole 311 of the second separator 3B overlaps with the second communication opening 231.

[0039] The inlet pipe 4 and outlet pipe 5 are cylindrical members. In this embodiment, the inlet pipe 4 and outlet pipe 5 are cylindrical. The central axis of the inlet pipe 4 and outlet pipe 5 is straight.

[0040] One end of each inlet pipe 4 and outlet pipe 5 in the axial direction is located within the internal space S. Hereinafter, the end of either the inlet pipe 4 or the outlet pipe 5 located within the internal space S will be referred to as the tip of the inlet pipe 4 or the outlet pipe 5.

[0041] The inlet pipe 4 is inserted through the first communication opening 221, the fixing hole 311 of the first separator 3A, and the sliding hole 312 of the second separator 3B. The inlet pipe 4 is joined to the first end plate 22 and the full-circumferential rising portion 33 of the first separator 3A, for example, by welding. On the other hand, the inlet pipe 4 is not joined to the second separator 3B. That is, the inlet pipe 4 is joined only to the first separator 3A, which is the first separator from the first end plate 22 side among the multiple separators 3A, 3B. The inlet pipe 4 is slidably held by the second separator 3B. The tip of the inlet pipe 4 is located in the third region X3, and the tip of the inlet pipe 4 faces the second end plate 23 with a gap between them.

[0042] The outlet pipe 5 is inserted through the second communication port 231, the fixing hole 311 of the second separator 3B, and the sliding hole 312 of the first separator 3A. The outlet pipe 5 is joined to the second end plate 23 and the full-circumferential rising portion 33 of the second separator 3B, for example, by welding. On the other hand, the outlet pipe 5 is not joined to the first separator 3A. That is, the outlet pipe 5 is joined only to the second separator 3B, which is the first separator from the second end plate 23 side among the multiple separators 3A, 3B. The outlet pipe 5 is slidably held by the first separator 3A. The tip of the outlet pipe 5 is located in the first region X1. The tip of the outlet pipe 5 faces the first end plate 22 with a gap between them.

[0043] The inlet pipe 4 and outlet pipe 5 may be joined to the full-circumferential rise portion 33 over the entire circumference surrounding the fixing hole 311, for example. Alternatively, the inlet pipe 4 and outlet pipe 5 may be joined to the full-circumferential rise portion 33 in a portion of the circumference surrounding the fixing hole 311. In the latter case, it is preferable that the inlet pipe 4 and outlet pipe 5 are joined to the full-circumferential rise portion 33, avoiding positions adjacent to the proximity position P1 shown in Figures 2 and 3. In other words, it is preferable that the joint with the inlet pipe 4 or outlet pipe 5 on the full-circumferential rise portion 33 be located at a position not adjacent to the proximity position P1.

[0044] As shown in Figure 1, multiple ventilation holes 41 are formed in the inlet pipe 4 from the first end plate 22 to its tip. Multiple ventilation holes 51 are formed in the outlet pipe 5 from the second end plate 23 to its tip. The multiple ventilation holes 41 and 51 are through holes that penetrate radially through the inlet pipe 4 or the outlet pipe 5.

[0045] Exhaust gas G from the internal combustion engine flows through the inlet pipe 4 and diffuses into the internal space S through multiple vent holes 41 or the opening at the end of the inlet pipe 4. The exhaust gas G diffused into each region X1 to X3 in the internal space S further diffuses to adjacent regions X1 to X3 through the communication holes 313 in the first separator 3A and the second separator 3B. This reduces the pressure of the exhaust gas G.

[0046] The exhaust gas G diffused within the internal space S enters the outlet pipe 5 through the opening at its tip or through multiple vents 51. The exhaust gas G then flows through the outlet pipe 5 and is discharged to the outside of the vehicle. The exhaust noise is reduced because the pressure of the exhaust gas G in the internal space S is reduced.

[0047] [1-2. Effects] According to the first embodiment described in detail above, the following effects can be obtained.

[0048] (1a) In the muffler 1, the inlet pipe 4 is joined to both the first end plate 22 and the first separator 3A. The outlet pipe 5 is joined to both the second end plate 23 and the second separator 3B.

[0049] With this configuration, when vibration occurs in the inlet pipe 4, the stress can be distributed to the joint between the inlet pipe 4 and the first end plate 22, and to the joint between the inlet pipe 4 and the first separator 3A. Similarly, when vibration occurs in the outlet pipe 5, the stress can be distributed to the joint between the outlet pipe 5 and the second end plate 23, and to the joint between the outlet pipe 5 and the second separator 3B. Therefore, the vibration strength of the muffler 1 can be improved.

[0050] (1b) In addition, the assembly accuracy of the inlet pipe 4 can be improved by joining the inlet pipe 4 to both the first end plate 22 and the first separator 3A. The assembly accuracy of the outlet pipe 5 can be improved by joining the outlet pipe 5 to both the second end plate 23 and the second separator 3B.

[0051] (1c) In order to improve the vibration strength of the muffler 1 and the assembly accuracy of the inlet pipe 4, it is also possible to join the inlet pipe 4 to the second separator 3B instead of the first separator 3A. However, if the exhaust gas G is hot, for example, the inlet pipe 4 may expand due to the heat of the exhaust gas G, as shown by the white arrow W1 in Figure 1, so-called thermal expansion. The inlet pipe 4 may expand due to thermal expansion toward the second end plate 23 with respect to the first end plate 22. For this reason, if the inlet pipe 4 expands due to thermal expansion, the portion of the inlet pipe 4 that contacts the second separator 3B is more likely to move axially than the portion that contacts the first separator 3A.

[0052] Therefore, in muffler 1, the inlet pipe 4 is joined to the first separator 3A rather than the second separator 3B. With this configuration, even if the inlet pipe 4 expands due to heat, the portion of the inlet pipe 4 fixed to the first separator 3A experiences relatively small axial movement. Consequently, the load on the joint between the inlet pipe 4 and the first separator 3A due to the thermal expansion of the inlet pipe 4 can be reduced. Furthermore, because the inlet pipe 4 is held slidably without being joined to the second separator 3B, thermal expansion of the inlet pipe 4 from the joint with the first separator 3A to the tip can be tolerated.

[0053] For similar reasons, the outlet pipe 5 is joined to the second separator 3B rather than the first separator 3A. This configuration reduces the load on the joint between the outlet pipe 5 and the second separator 3B due to thermal expansion of the outlet pipe 5. Therefore, the thermal durability of the muffler 1 can be improved. In addition, because the outlet pipe 5 is held slidably without being joined to the first separator 3A, thermal expansion of the outlet pipe 5 from the joint with the second separator 3B to the tip can be tolerated. In Figure 1, the direction in which the outlet pipe 5 may expand due to thermal expansion is indicated by the white arrow W2.

[0054] (1d) Furthermore, through diligent research by the inventors, it was found that if the inlet pipe 4 were not joined to the first separator 3A but to the second separator 3B, the inlet pipe 4 would tend to expand even more due to the heat towards the second end plate 23. This is thought to be due to a decrease in the restraining force of the inlet pipe 4 by the first separator 3A. Therefore, in this embodiment, by joining the inlet pipe 4 to the first separator 3A and not to the second separator 3B, it is possible to make the inlet pipe 4 less susceptible to thermal expansion. As the inlet pipe 4 is less susceptible to thermal expansion, the load on the joint between the inlet pipe 4 and the first separator 3A can be reduced.

[0055] Similarly, in this embodiment, the outlet pipe 5 is joined to the second separator 3B but not to the first separator 3A, which makes it less susceptible to thermal expansion of the outlet pipe 5. Because the outlet pipe 5 is less susceptible to thermal expansion, the load on the joint between the outlet pipe 5 and the second separator 3B can be reduced. Therefore, as described in (1c) above, the thermal durability of the muffler 1 can be improved.

[0056] (1e) The first separator 3A and the second separator 3B are provided with a partial rise portion 34 and a relief portion 35 along the edge of the sliding hole 312.

[0057] With this configuration, compared to a configuration in which a raised portion is provided around the entire edge of the sliding hole 312, the restraining force exerted by the second separator 3B on the inlet pipe 4 inserted through the sliding hole 312 can be further reduced. Therefore, when the inlet pipe 4 attempts to expand due to heat, the load on the contact portion of the second separator 3B with the inlet pipe 4, i.e., the partial raised portion 34, can be further reduced.

[0058] Similarly, the restraining force exerted by the first separator 3A on the outlet pipe 5 inserted through the sliding hole 312 can be further reduced. Therefore, when the outlet pipe 5 attempts to expand due to heat, the load on the contact portion of the first separator 3A with the outlet pipe 5, i.e., the partial rise portion 34, can be further reduced. Consequently, the thermal durability of the muffler 1 can be further improved.

[0059] (1f) Furthermore, by further reducing the restraining force of the second separator 3B on the inlet pipe 4, the friction noise between the inlet pipe 4 and the second separator 3B can be reduced. Similarly, by further reducing the restraining force of the first separator 3A on the outlet pipe 5, the friction noise between the outlet pipe 5 and the first separator 3A can be reduced.

[0060] (1g) Multiple relaxation portions 35 are arranged at equal intervals along the edge of the sliding hole 312. With this configuration, the restraining force of the second separator 3B on the inlet pipe 4 inserted through the sliding hole 312 can be reduced uniformly in the circumferential direction surrounding the sliding hole 312. The restraining force of the first separator 3A on the outlet pipe 5 inserted through the sliding hole 312 can be reduced uniformly in the circumferential direction surrounding the sliding hole 312. Therefore, the effects of (1e) and (1f) above can be obtained while suppressing excessive reduction of the holding force of the partial rise portion 34 on the inlet pipe 4 or the outlet pipe 5. Furthermore, it is possible to easily form multiple relaxation portions 35 during the manufacturing process of the first separator 3A and the second separator 3B.

[0061] (1h) In the first separator 3A, the inlet pipe 4 is inserted through the fixing hole 311 and the outlet pipe 5 is inserted through the sliding hole 312. In this state, if the inlet pipe 4 expands due to heat, the all-around rising portion 33 deforms by being dragged by the inlet pipe 4, as shown in Figure 4A. This is because the all-around rising portion 33 is joined to the inlet pipe 4.

[0062] On the other hand, if the outlet pipe 5 expands due to heat, the partial riser portion 34 deforms as it is dragged by the outlet pipe 5, as shown by the dashed line in Figure 4B. However, the partial riser portion 34 is not joined to the outlet pipe 5. Therefore, when the frictional force between the partial riser portion 34 and the outlet pipe 5 can no longer withstand the elastic force of the partial riser portion 34, the partial riser portion 34 returns to its original shape, as shown by the solid line in Figure 4B.

[0063] In the second separator 3B, the outlet pipe 5 is inserted through the fixing hole 311, and the inlet pipe 4 is inserted through the sliding hole 312. In the second separator 3B, as in the first separator 3A, the entire circumference rising portion 33 deforms in accordance with the thermal expansion of the outlet pipe 5. The partial rising portion 34 also deforms in accordance with the thermal expansion of the inlet pipe 4, but when the frictional force between the partial rising portion 34 and the inlet pipe 4 can no longer withstand the elastic force of the partial rising portion 34, the partial rising portion 34 returns to its original shape.

[0064] Here, when the full-circumference rising portion 33 is deformed, stress is likely to occur in the full-circumference rising portion 33 itself and in the portion of the main body 31 adjacent to the base of the full-circumference rising portion 33 (i.e., the portion surrounding the fixing hole 311). When the partial rising portion 34 is deformed, stress is likely to occur in the partial rising portion 34 itself and in the portion of the main body 31 adjacent to the base of the partial rising portion 34. For this reason, if the distance between the full-circumference rising portion 33 and the partial rising portion 34 is too close, stress may concentrate in the portion of the main body 31 sandwiched between the full-circumference rising portion 33 and the partial rising portion 34.

[0065] If stress were to concentrate in the above-mentioned area, the full-circumference rising section 33 would be more susceptible to the effects of the stress than the partial rising section 34. This is because the full-circumference rising section 33 is joined to the inlet pipe 4 or outlet pipe 5, resulting in a lower degree of freedom of deformation than the partial rising section 34, making it more difficult to distribute stress. Therefore, if stress were to concentrate in the above-mentioned area, the load on the full-circumference rising section 33 could increase.

[0066] Therefore, in the first separator 3A and the second separator 3B of this embodiment, the multiple relaxation sections 35 are configured to include proximity relaxation sections 35a. In other words, the partial rising section 34 is not located at the proximity position P2.

[0067] With this configuration, the distance between the full-circumference rising portion 33 and the partial rising portion 34 can be increased compared to the modified separator 3C shown in Figures 5 and 6. Therefore, it is possible to suppress stress concentration in the portion of the main body 31 sandwiched between the full-circumference rising portion 33 and the partial rising portion 34, specifically the portion including the shortest line segment L. As a result, it is possible to reduce the load on the full-circumference rising portion 33 when the inlet pipe 4 or outlet pipe 5 undergoes thermal expansion. Consequently, the thermal durability of the full-circumference rising portion 33 can be improved. By improving the thermal durability of the full-circumference rising portion 33, the thermal durability of the first separator 3A and the second separator 3B, and consequently the thermal durability of the muffler 1, can be further improved.

[0068] (1i) For example, by improving the thermal durability of the all-around rising portion 33, it is possible to avoid increasing the number of joints in the all-around rising portion 33 or requiring a long time to adjust the joint positions. This also makes it possible to reduce the manufacturing costs of the first separator 3A and the second separator 3B.

[0069] The modified separator 3C has the same configuration as the first separator 3A of this embodiment, except for the positions of the multiple partial risers 34. In the modified separator 3C, one of the multiple partial risers 34 is located in a range that includes the proximity position P2. That is, the modified separator 3C does not have a proximity mitigation portion 35a. Even with such a configuration, it is possible to obtain the effects described in (1e) to (1g) above.

[0070] (1j) As described in (1h) above, when the entire circumference rising portion 33 is deformed, stress is likely to occur in the entire circumference rising portion 33 itself. In particular, stress is likely to occur at the joint between the entire circumference rising portion 33 and the inlet pipe 4 or outlet pipe 5. Therefore, in the entire circumference rising portion 33, the joint between the inlet pipe 4 or outlet pipe 5 is located, for example, in a position not adjacent to the proximity position P1.

[0071] This configuration allows for a wider gap between the joint of the full-circumference rising portion 33 and the partial rising portion 34. Therefore, stress concentration in the portion of the main body 31 that includes the shortest line segment L can be further suppressed. As a result, the load on the full-circumference rising portion 33 when the inlet pipe 4 or outlet pipe 5 undergoes thermal expansion can be further reduced. Consequently, the thermal durability of the first separator 3A and the second separator 3B, and thus the thermal durability of the muffler 1, can be further improved.

[0072] [1-3. Correspondence] In the first embodiment, the shell 21, the first end plate 22, and the second end plate 23 correspond to examples of the peripheral wall, the first closing portion, and the second closing portion, respectively. The fixing hole 311 of the first separator 3A and the sliding hole 312 of the second separator 3B correspond to examples of the first through hole, respectively. The sliding hole 312 of the first separator 3A and the fixing hole 311 of the second separator 3B correspond to examples of the second through hole, respectively. The inlet pipe 4 and the outlet pipe 5 correspond to examples of the first pipe and the second pipe, respectively.

[0073] [2. Second Embodiment] [2-1. Structure] The second embodiment has the same basic configuration as the first embodiment, so the differences will be explained below. Note that the same reference numerals as in the first embodiment indicate the same components, and refer to the preceding description.

[0074] The muffler 1A of the second embodiment shown in Figure 7 comprises an outer shell member 2A, a first separator 3A, a second separator 3B, a third separator 3D, an inlet pipe 4A, a first outlet pipe 5A, and a second outlet pipe 5B.

[0075] The outer shell member 2A has a configuration that is generally the same as that of the outer shell member 2 described above. However, the shell 21A of the outer shell member 2A has an insertion opening 213 formed between the first end 211 and the second end 212. The insertion opening 213 is an opening that connects the internal space S with the outside of the outer shell member 2.

[0076] The first separator 3A and the second separator 3B are as described in detail in the first embodiment. The third separator 3D has a configuration that is generally the same as that of the first separator 3A and the second separator 3B. However, while the first separator 3A and the second separator 3B have a fixing hole 311 and a sliding hole 312, the third separator 3D has two sliding holes 312. In the third separator 3D as well, the aforementioned multiple partial risers 34 and multiple relief portions 35 are provided along the edges of the sliding holes 312.

[0077] The third separator 3D is located within the internal space S together with the first separator 3A and the second separator 3B. The third separator 3D is located between the first separator 3A and the second separator 3B. The third separator 3D faces the first separator 3A and the second separator 3B with a gap between them. The second separator 3B is located on the second end plate 23 side of the insertion opening 213. The third separator 3D is located on the first end plate 22 side of the insertion opening 213.

[0078] Viewed from the axial direction of the shell 21A, the fixing hole 311 of the first separator 3A overlaps with the sliding hole 312 of the third separator 3D and the sliding hole 312 of the second separator 3B. Also, viewed from the axial direction of the shell 21A, the fixing hole 311 of the first separator 3A overlaps with the first communication opening 221. Viewed from the axial direction of the shell 21A, the fixing hole 311 of the second separator 3B overlaps with the sliding hole 312 of the third separator 3D and the sliding hole 312 of the first separator 3A. Also, viewed from the axial direction of the shell 21A, the fixing hole 311 of the second separator 3B overlaps with the second communication opening 231.

[0079] The first separator 3A, the second separator 3B, and the third separator 3D partition the internal space S. Specifically, the first separator 3A, the second separator 3B, and the third separator 3D divide the internal space S into four areas: the first area Y1, the second area Y2, the third area Y3, and the fourth area Y4. The first area Y1 is the area on the first end plate 22 side of the first separator 3A. The second area Y2 is the area between the first separator 3A and the third separator 3D. The third area Y3 is the area between the third separator 3D and the second separator 3B. The fourth area Y4 is the area on the second end plate 23 side of the second separator 3B. The insertion opening 213 faces the third area Y3.

[0080] Inlet pipe 4A has a configuration that is generally similar to inlet pipe 4 described above. However, inlet pipe 4A is inserted into the insertion port 213 instead of the first communication port 221. The tip of inlet pipe 4A is located in the internal space S (specifically, the third region Y3).

[0081] The first outlet pipe 5A has a configuration that is generally the same as the outlet pipe 5 described above. However, the first outlet pipe 5A is inserted through the first communication port 221, the fixing hole 311 of the first separator 3A, the sliding hole 312 of the third separator 3D, and the sliding hole 312 of the second separator 3B. The first outlet pipe 5A is joined to the first end plate 22 and the full-circumference rising portion 33 of the first separator 3A. On the other hand, the first outlet pipe 5A is not joined to the second separator 3B and the third separator 3D. That is, the first outlet pipe 5A is joined only to the first separator 3A, which is the first separator from the first end plate 22 side among the multiple separators 3A, 3B, and 3D, and is not joined to the remaining second separator 3B and third separator 3D. The first outlet pipe 5A is slidably held by the second separator 3B and the third separator 3D. The tip of the first outlet pipe 5A is located in the fourth region Y4.

[0082] The second outlet pipe 5B has a configuration that is generally similar to that of the outlet pipe 5 described above. However, the second outlet pipe 5B is inserted through the second communication port 231, the fixing hole 311 of the second separator 3B, the sliding hole 312 of the third separator 3D, and the sliding hole 312 of the first separator 3A. The second outlet pipe 5B is joined to the entire circumference rising portion 33 of the second end plate 23 and the second separator 3B. On the other hand, the second outlet pipe 5B is not joined to the first separator 3A and the third separator 3D. That is, the second outlet pipe 5B is joined only to the second separator 3B, which is the first separator from the second end plate 23 side among the multiple separators 3A, 3B, and 3D, and is not joined to the remaining first separator 3A and third separator 3D. The second outlet pipe 5B is slidably held by the first separator 3A and the third separator 3D. The tip of the second outlet pipe 5B is positioned in the first region Y1.

[0083] In the muffler 1A of the second embodiment, as in the first embodiment, the first outlet pipe 5A and the second outlet pipe 5B can expand due to heat. As shown by the white arrow W3 in Figure 7, the first outlet pipe 5A can expand due to heat toward the second end plate 23 with respect to the first end plate 22. As shown by the white arrow W4 in Figure 7, the second outlet pipe 5B can expand due to heat toward the first end plate 22 with respect to the second end plate 23.

[0084] [2-2. Effects] According to the second embodiment described in detail above, the same effects as the first embodiment can be obtained.

[0085] [2-3. Correspondence] In the second embodiment, the shell 21A, the first end plate 22, and the second end plate 23 correspond to examples of the peripheral wall, the first closing portion, and the second closing portion, respectively. The fixing hole 311 of the first separator 3A, the sliding hole 312 of the second separator 3B, and one of the two sliding holes 312 in the third separator 3D each correspond to an example of the first through hole. The sliding hole 312 of the first separator 3A, the fixing hole 311 of the second separator 3B, and the other of the two sliding holes 312 in the third separator 3D each correspond to an example of the second through hole. The first outlet pipe 5A and the second outlet pipe 5B correspond to examples of the first pipe and the second pipe, respectively.

[0086] [3. Third Embodiment] [3-1. Structure] The third embodiment has the same basic configuration as the first embodiment, so the differences will be explained below. Note that the same reference numerals as in the first embodiment indicate the same components, and refer to the preceding description.

[0087] The muffler 1B of the third embodiment shown in Figure 8 comprises an outer shell member 2B, a first separator 3E, a second separator 3F, a third separator 3G, a first inlet pipe 4B, a second inlet pipe 4C, and an outlet pipe 5C.

[0088] The outer shell member 2B has a configuration that is generally similar to that of the outer shell member 2. However, the first end plate 22A of the outer shell member 2B has a third communication opening 222 in addition to the first communication opening 221. The third communication opening 222 is an opening that connects the internal space S to the outside of the outer shell member 2. When the first end plate 22A and the second end plate 23 are positioned at the first end 211 and the second end 212 of the shell 21, respectively, when viewed from the axial direction of the shell 21, neither the first communication opening 221 nor the third communication opening 222 overlaps with the second communication opening 231.

[0089] The first separator 3E, the second separator 3F, and the third separator 3G have a configuration that is generally the same as the first separator 3A described above. However, the first separator 3A has one fixing hole 311 and one sliding hole 312. In contrast, the first separator 3E has two fixing holes 311. The second separator 3F has one fixing hole 311 and two sliding holes 312. The third separator 3G has three sliding holes 312. In the first separator 3E, the second separator 3F, and the third separator 3G, the aforementioned full-circumference rising portion 33 is provided along the edge of the fixing hole 311. In addition, the aforementioned multiple partial rising portions 34 and multiple relaxation portions 35 are provided along the edge of the sliding hole 312.

[0090] The first separator 3E, the second separator 3F, and the third separator 3G are arranged within the internal space S. The third separator 3G is positioned between the first separator 3E and the second separator 3F. The third separator 3G faces the first separator 3E and the second separator 3F, each with a space between them. Similar to the second embodiment, the first separator 3E, the second separator 3F, and the third separator 3G divide the internal space S into four areas: the first area Y1, the second area Y2, the third area Y3, and the fourth area Y4.

[0091] Viewed from the axial direction of the shell 21, the two fixing holes 311 of the first separator 3E overlap with the sliding holes 312 of the third separator 3G and the sliding holes 312 of the second separator 3F, respectively. Viewed from the axial direction of the shell 21, one of the two fixing holes 311 of the first separator 3E overlaps with the first communication opening 221. Also, viewed from the axial direction of the shell 21, the other of the two fixing holes 311 of the first separator 3E overlaps with the third communication opening 222. Viewed from the axial direction of the shell 21, the fixing hole 311 of the second separator 3F overlaps with the sliding hole 312 of the third separator 3G. Also, viewed from the axial direction of the shell 21, the fixing hole 311 of the second separator 3F overlaps with the second communication opening 231.

[0092] The first inlet pipe 4B and the second inlet pipe 4C have a configuration that is generally the same as the inlet pipe 4 described above. However, the first inlet pipe 4B is inserted through the first communication port 221, the fixing hole 311 of the first separator 3E, the sliding hole 312 of the third separator 3G, and the sliding hole 312 of the second separator 3F. The second inlet pipe 4C is inserted through the third communication port 222, the fixing hole 311 of the first separator 3E, the sliding hole 312 of the third separator 3G, and the sliding hole 312 of the second separator 3F.

[0093] The first inlet pipe 4B and the second inlet pipe 4C are joined to the first end plate 22A and the full-circumferential rising portion 33 of the first separator 3E. On the other hand, the first inlet pipe 4B and the second inlet pipe 4C are not joined to the second separator 3F and the third separator 3G. That is, the first inlet pipe 4B and the second inlet pipe 4C are joined only to the first separator 3E, which is the first separator from the first end plate 22A side among the multiple separators 3E to 3G, and are not joined to the remaining second separator 3F and third separator 3G. The first inlet pipe 4B and the second inlet pipe 4C are slidably held by the second separator 3F and the third separator 3G. The ends of the first inlet pipe 4B and the second inlet pipe 4C are located in the fourth region Y4.

[0094] The outlet pipe 5C has a configuration that is generally the same as the outlet pipe 5 described above. However, the outlet pipe 5C is inserted through the second communication port 231, the fixing hole 311 of the second separator 3F, and the sliding hole 312 of the third separator 3D. The outlet pipe 5C is joined to the second end plate 23 and the full-circumference rising portion 33 of the second separator 3F. On the other hand, the outlet pipe 5C is not joined to the first separator 3E and the third separator 3G. That is, the outlet pipe 5C is joined only to the second separator 3F, which is the first separator from the second end plate 23 side among the multiple separators 3E to 3G, and is not joined to the remaining first separator 3E and third separator 3G. The outlet pipe 5C is not even inserted into the first separator 3E. The outlet pipe 5C is slidably held by the third separator 3G. The tip of outlet pipe 5C is located in the second region Y2.

[0095] In the muffler 1B of the third embodiment, as in the first embodiment, the first inlet pipe 4B, the second inlet pipe 4C, and the outlet pipe 5C can expand due to heat. As shown by the white arrows W5 and W6 in Figure 8, the first inlet pipe 4B and the second inlet pipe 4C can expand due to heat toward the second end plate 23 with respect to the first end plate 22A. As shown by the white arrow W7 in Figure 8, the outlet pipe 5C can expand due to heat toward the first end plate 22A with respect to the second end plate 23.

[0096] [3-2. Effects] According to the third embodiment described in detail above, the same effects as the first embodiment can be obtained.

[0097] [3-3. Correspondence] In the third embodiment, the shell 21, the first end plate 22A, and the second end plate 23 correspond to examples of the peripheral wall, the first closing portion, and the second closing portion, respectively. The two fixing holes 311 of the first separator 3E, the two sliding holes 312 of the second separator 3F, and two of the three sliding holes 312 in the third separator 3G each correspond to examples of the first through holes. The fixing hole 311 of the second separator 3F and the remaining one of the three sliding holes 312 in the third separator 3G each correspond to examples of the second through holes. The first inlet pipe 4B and the second inlet pipe 4C each correspond to examples of the first pipe. The outlet pipe 5C corresponds to an example of the second pipe.

[0098] [4. Other Embodiments] While embodiments of this disclosure have been described above, it goes without saying that this disclosure is not limited to the embodiments described above and can take various forms.

[0099] (4a) In the first embodiment described above, muffler 1 comprises two separators 3A and 3B. In the second embodiment described above, muffler 1A comprises three separators 3A, 3B, and 3D. In the third embodiment described above, muffler 1B also comprises three separators 3E to 3G. However, the muffler may comprise, for example, four or more separators. That is, the muffler may comprise N separators, where N is a positive number satisfying 2 ≤ N.

[0100] (4b) In the first embodiment described above, all separators 3A and 3B are provided with a fixing hole 311 or a sliding hole 312 as an example of a first through hole for inserting the inlet pipe 4. The inlet pipe 4 corresponds to an example of the first pipe.

[0101] However, the first pipe does not necessarily have to be inserted through all the separators. For example, if the muffler has N separators, the first pipe may be inserted through the first through-holes of the first to x separators from the first end plate side, where x is a positive number satisfying 2 ≤ x ≤ N. In this case, the first pipe is joined only to the first separator from the first end plate side, and is slidably held by the remaining separators.

[0102] Furthermore, the configuration in which the first pipe is inserted through all the separators, as in the first to third embodiments described above, corresponds to a configuration where x satisfies x=N.

[0103] (4c) In the first embodiment described above, all separators 3A and 3B are provided with a fixing hole 311 or a sliding hole 312 as an example of a second through hole for inserting the outlet pipe 5. The outlet pipe 5 corresponds to an example of a second pipe.

[0104] However, the second pipe does not necessarily have to be inserted through all separators. For example, if the muffler has N separators, the second pipe may be inserted through the second through-holes of the first to yth separators from the second end plate side, where y is a positive number satisfying 1 ≤ y ≤ N and N+1 ≤ x + y. The fact that y satisfies N+1 ≤ x + y means that at least one of the N separators is inserted through both the first and second pipes.

[0105] Furthermore, the configuration in which the second pipe is inserted through all the separators, as in the first and second embodiments described above, corresponds to a configuration in which y satisfies y=N.

[0106] (4d) As in the first to third embodiments described above, if y is a positive number satisfying 2 ≤ y ≤ N and N+1 ≤ x + y, the second pipe may be joined only to the first separator from the second end plate side and slidably held by the remaining separators.

[0107] Furthermore, for example, regardless of whether y satisfies 1 ≤ y ≤ N or 2 ≤ y ≤ N, the second pipe does not necessarily have to be joined to the first separator from the second end plate side. For example, the second pipe may be joined to the second end plate and slidably held by the first to yth separators from the second end plate side. Even in this case, as in the first to third embodiments and (4b) above, the first pipe is joined to both the first end plate and the first separator from the first end plate side. Therefore, at least for the first pipe, stress can be distributed when vibration occurs. As a result, the vibration strength of the muffler can be improved.

[0108] (4e) In the separators 3A to 3D, 3F, and 3G of the first to third embodiments and their modifications, the multiple relief portions 35 do not rise from the edge of the sliding hole 312 at all. However, the shape of the relief portion is not particularly limited. For example, the relief portion may be a part that rises from the edge of the sliding hole, but within a range that does not reach the height of the partially raised portion. Alternatively, for example, the relief portion may be a part where the edge of the sliding hole is recessed. In these cases as well, the same effect as in (1e) above can be obtained. The degree of this effect tends to be higher the lower the height of the relief portion and the more the relief portion is recessed away from the first or second pipe inserted into the sliding hole.

[0109] (4f) In the separators 3A to 3D, 3F, and 3G of the first to third embodiments and their modifications, a plurality of partial risers 34 are arranged along the edge of the sliding hole 312. The plurality of partial risers 34 are of equal height. The plurality of partial risers 34 are of equal circumferential dimensions surrounding the sliding hole 312.

[0110] However, if there are multiple partial risers, these multiple partial risers do not necessarily have to be of equal height to one another. For example, at least one of the multiple partial risers may have a different height from the others.

[0111] Furthermore, if there are multiple partial risers, the dimensions of these multiple partial risers in the circumferential direction surrounding the sliding hole do not necessarily have to be equal to each other. For example, at least one of the multiple partial risers may have different dimensions in the circumferential direction surrounding the sliding hole compared to the other partial risers.

[0112] (4g) In the separators 3A to 3D, 3F, and 3G of the first to third embodiments and their modifications described above, a plurality of relief portions 35 are arranged along the edge of the sliding hole 312. In the circumferential direction surrounding the sliding hole 312, the dimensions of each of the plurality of relief portions 35 are approximately equal to the dimensions of the adjacent partial rise portion 34. Furthermore, the dimensions of the plurality of relief portions 35 in the circumferential direction surrounding the sliding hole 312 are equal to those of each other.

[0113] However, the dimensions of the circumferential relief portion are not particularly limited. For example, the dimensions of the circumferential relief portion may be smaller than the dimensions of adjacent partial rise portions. Also, if there are multiple relief portions, the dimensions of these multiple relief portions in the circumferential direction surrounding the sliding hole do not necessarily have to be equal to each other. For example, at least one of the multiple relief portions may have different dimensions in the circumferential direction surrounding the sliding hole compared to the other relief portions.

[0114] (4h) The separators 3A to 3D, 3F, and 3G of the first to third embodiments and modified examples described above have a plurality of partial risers 34 and a plurality of relaxation sections 35. However, the number of partial risers and relaxation sections is not particularly limited. The number of partial risers and the number of relaxation sections may be, for example, one or multiple.

[0115] (4i) For example, when the separator has multiple relief sections, as in the first to third embodiments and modified examples above, the arrangement of the multiple relief sections along the edge of the sliding hole is not particularly limited. The multiple relief sections do not necessarily have to be arranged at equal intervals along the edge of the sliding hole.

[0116] (4j) In the first to third embodiments and modified versions of the separators 3A to 3D, 3F, and 3G described above, a partial rise portion 34 and a relief portion 35 are provided along the edge of the sliding hole 312. However, each separator does not necessarily have to have a partial rise portion and a relief portion. For example, in any of the separators, a full-circumference rise portion may be provided along the edge of the sliding hole instead of a partial rise portion and a relief portion.

[0117] (4k) The functions of one component in the above embodiment may be distributed among multiple components, or the functions of multiple components may be integrated into one component. Also, some parts of the configuration of the above embodiment may be omitted. Also, at least some parts of the configuration of the above embodiment may be added to, replaced with, etc., the configuration of other above embodiments.

[0118] [Technical concepts disclosed in this specification] [Item 1] A muffler installed in the exhaust gas passage from an internal combustion engine, An outer shell member having a cylindrical peripheral wall portion surrounding the internal space, and a first closing portion and a second closing portion that respectively close two openings in the axial direction of the peripheral wall portion, N separators (where N is a positive number satisfying 2 ≤ N) are plate-shaped members arranged in the axial direction of the peripheral wall portion and partition the internal space, The first pipe and the second pipe are cylindrical members whose tips are positioned within the internal space, Equipped with, The first closure portion is formed with a first communication opening that connects the internal space with the outside of the outer shell member. The second closure portion is formed with a second communication opening that connects the internal space and the outside. Of the N separators, the first to x separators from the first closing portion side (where x is a positive number satisfying 2 ≤ x ≤ N) have a first through-hole formed through them. Of the N separators, the separators from the 1st to the yth from the second closing portion side (where y is a positive number satisfying 1 ≤ y ≤ N and N+1 ≤ x + y) have a second through-hole formed through the separator. The first pipe is inserted through the first communication port and the first through-holes of the first to xth separators from the first closing portion side, joined to the first closing portion and the first separator from the first closing portion side, and slidably held by the second to xth separators from the first closing portion side. A muffler in which the second pipe is inserted through the second communication port and the second through holes of the 1st to yth separators from the second closing portion side, and is joined to at least the second closing portion.

[0119] [Item 2] The muffler described in item 1, y is a positive number satisfying 2 ≤ y ≤ N and N+1 ≤ x + y. A muffler in which the second pipe is joined to the second closure and the first separator from the second closure side, and is slidably held by the second to yth separators from the second closure side.

[0120] [Item 3] A muffler as described in item 1 or item 2, y is a positive number that satisfies y=N, The first separator from the first closure side is, At least one rising portion rising from the edge of the second through hole, Along the edge of the second through hole, adjacent to the at least one rising portion, and having a height lower than the at least one rising portion, It has, A muffler in which the at least one mitigation portion includes a proximity mitigation portion arranged in a range that includes a position at the edge of the second through-hole where the distance from the first through-hole is minimized.

[0121] [Item 4] A muffler described in any one of items 1 through 3, y is a positive number that satisfies y=N, The first separator from the first closure side is, At least one rising portion rising from the edge of the second through hole, Along the edge of the second through hole, adjacent to the at least one rising portion, and having a height lower than the at least one rising portion, It has, The aforementioned at least one relaxation section includes a plurality of relaxation sections, A muffler in which the plurality of mitigation portions are arranged at equal intervals along the edge of the second through hole. [Explanation of Symbols]

[0122] 1,1A,1B...Muffler, 2,2A,2B...Outer shell member, 3A~3G...Separator, 4,4A~4C...Inlet pipe, 5,5A~5C...Outlet pipe, 21,21A...Shell, 22,22A,23...End plate, 31...Main body, 32...Outer edge, 33...Full circumference rise, 34...Partial rise, 35...Relaxation part, 35a...Proximity relaxation part, 221...First communication port, 222...Third communication port, 231...Second communication port, 311...Fixing hole, 312...Sliding hole, 313...Communication hole, G...Exhaust gas, L...Proximity line segment, P1,P2...Proximity position, S...Internal space, X1~X3,Y1~Y4...Region, W1~W7...Arrow.

Claims

1. A muffler installed in the exhaust gas passage from an internal combustion engine, An outer shell member having a cylindrical peripheral wall portion surrounding the internal space, and a first closing portion and a second closing portion that respectively close two openings in the axial direction of the peripheral wall portion, N separators (where N is a positive number satisfying 2 ≤ N) are plate-shaped members arranged in the axial direction of the peripheral wall portion and partition the internal space, The first pipe and the second pipe are cylindrical members whose tips are positioned within the internal space, Equipped with, The first closure portion is formed with a first communication opening that connects the internal space with the outside of the outer shell member. The second closure portion is formed with a second communication opening that connects the internal space and the outside. Of the N separators, the first to x separators from the first closing portion side (where x is a positive number satisfying 2 ≤ x ≤ N) have a first through-hole formed through them. Of the N separators, the separators from the 1st to the yth from the second closing portion side (where y is a positive number satisfying 1 ≤ y ≤ N and N + 1 ≤ x + y) have a second through-hole formed through the separator. The first pipe is inserted through the first communication port and the first through-holes of the separators numbered 1 to x from the first closing portion side, joined to the first closing portion and the first separator from the first closing portion side, and slidably held by the separators numbered 2 to x from the first closing portion side. A muffler in which the second pipe is inserted through the second communication port and the second through holes of the first to yth separators from the second closing portion side, and is joined to at least the second closing portion.

2. The muffler according to claim 1, y is a positive number satisfying 2 ≤ y ≤ N and N + 1 ≤ x + y. A muffler in which the second pipe is joined to the second closure and the first separator from the second closure side, and is slidably held by the second to yth separators from the second closure side.

3. A muffler according to claim 1 or claim 2, y is a positive number that satisfies y = N, The first separator from the first closure side is, At least one rising portion that rises from the edge of the second through hole, Along the edge of the second through hole, there is at least one easing portion adjacent to the at least one rising portion, which is lower in height than the at least one rising portion, It has, A muffler in which the at least one mitigation portion includes a proximity mitigation portion arranged in a range that includes a position at the edge of the second through-hole where the distance from the first through-hole is minimized.

4. The muffler according to claim 3, The at least one relaxation section includes a plurality of relaxation sections, including the adjacent relaxation section. The muffler is characterized in that the plurality of mitigation sections are arranged at equal intervals along the edge of the second through-hole.

Images