JP2023150422A - Exhaust system and first and second exhaust devices - Google Patents

Abstract

To reduce manufacturing costs of an exhaust system.SOLUTION: An exhaust system of a vehicle includes first and second exhaust devices. The first exhaust device includes: a first outer pipe part; and a first inner pipe part located at the inner side of the first outer pipe part. The second exhaust device includes: a second outer pipe part joined to the first outer pipe part; a second inner pipe part located at the inner side of the second outer pipe part; and a holding member. The holding member is provided between the second outer pipe part and the second inner pipe part and may slide relative to an inner peripheral surface of the second outer pipe part and an outer peripheral surface of the second inner pipe part. The holding member slidably contacts with an outer peripheral surface of the first inner pipe part.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to exhaust systems and the like.

In an exhaust pipe having a double pipe structure, a technique is known in which the inner pipe is held by arranging a wire mesh between the inner pipe and the outer pipe (for example, Patent Document 1). According to such a configuration, the wire mesh can absorb the difference in thermal expansion between the inner tube and the outer tube.

JP2002-054437A

However, when wire mesh is arranged at multiple locations between the inner tube and the outer tube as in the technique of Patent Document 1, the number of parts increases, and there is a concern that manufacturing costs will increase.
One aspect of the present disclosure aims to reduce the manufacturing cost of an exhaust system.

One aspect of the present disclosure is an exhaust system including first and second exhaust devices configured to form an exhaust gas flow path in a vehicle, the first exhaust device including a first outer pipe portion and a first exhaust gas flow path. An inner tube part. The first outer tube portion has a first outer tube opening configured to be connected to a second outer tube opening of the second exhaust device. The first inner tube part is located inside the first outer tube part, is provided so as to protrude outward from the first outer tube opening, and has a first inner tube opening. The second exhaust device includes a second outer tube section, a second inner tube section, and a holding member. The second outer tube section has a second outer tube opening and is configured to be joined to the first outer tube section. The second inner tube part has a second inner tube opening located inside the second outer tube opening, and is located inside the second outer tube part. The holding member is a portion provided between the inner circumferential surface of the second outer tube portion and a portion of the outer circumferential surface of the second inner tube portion adjacent to the second inner tube opening, and is a portion of the second outer tube portion. This is a portion that can slide on one of the inner circumferential surface of the second inner tube portion and the outer circumferential surface of the second inner tube portion. Further, the holding member is configured to slidably abut against the outer circumferential surface of the first inner tube portion.

According to the above configuration, the holding member provided in the second exhaust device can adjust the difference in thermal expansion between the second outer tube portion and the second inner tube portion in the second exhaust device and the first outer tube in the first exhaust device. It is possible to absorb the difference in thermal elongation between the inner tube section and the first inner tube section. Therefore, the number of parts in the exhaust system can be reduced, and the manufacturing cost of the exhaust system can be reduced.

In one aspect of the present disclosure, a reduced portion that becomes thinner toward the first inner tube opening may be provided in the first inner tube portion near the first inner tube opening.
According to the above configuration, it becomes easy to arrange the first inner tube part so that the holding member is slidably abutted on the outer circumferential surface of the first inner tube part. This facilitates the manufacture of the exhaust system.

In one aspect of the present disclosure, at least one of the first and second exhaust devices is configured to perform muffling by causing exhaust gas to flow into a space between the inner tube portion and the outer tube portion. Good too.

According to the above configuration, it is possible to reduce the manufacturing cost of an exhaust system including an exhaust device that muffles noise by causing exhaust gas to flow into the space.
In one aspect of the present disclosure, of the first and second exhaust devices, the one located on the upstream side in the flow direction of exhaust gas is an upstream exhaust device, and the upstream exhaust device has an inner pipe portion and an outer pipe portion. The structure may be such that the noise is muffled by letting exhaust gas flow into the space between them. The upstream exhaust device may further include a space in which a purification member for purifying exhaust gas is disposed. The inner pipe portion of the upstream exhaust device may be located downstream in the exhaust gas flow direction with respect to the space in which the purification member is disposed.

According to the above configuration, the space on the downstream side of the purification member can be used as a sound deadening space. Therefore, the space for arranging members used for purifying exhaust gas and muffling noise and the number of parts can be reduced.
In one aspect of the present disclosure, at least one of the first and second exhaust devices is configured to perform noise reduction using sound wave interference using a space between the inner tube portion and the outer tube portion. It's okay.

According to the above configuration, it is possible to reduce the manufacturing cost of an exhaust system including an exhaust device that performs noise reduction using sound wave interference.
Further, one aspect of the present disclosure is a first or second exhaust device in the exhaust system. According to these exhaust devices, the number of parts in the exhaust system can be reduced, and the manufacturing cost of the exhaust system can be reduced.

FIG. 1 is a cross-sectional view of the exhaust system of the first embodiment. It is a sectional view of the exhaust system of a 2nd embodiment.

Embodiments of the present disclosure will be described below with reference to the drawings. Note that the embodiments of the present disclosure are not limited to the embodiments described below, and may take various forms as long as they fall within the technical scope of the present disclosure.

[First embodiment]
[1. overview]
The exhaust system 1 of the first embodiment is mounted on a vehicle, and includes a main muffler (not shown), first and second sub-mufflers 2 and 5, and forms a flow path for exhaust gas from the engine of the vehicle (not shown). (see 1). Note that the exhaust system 1 does not need to include a main muffler. Specifically, the opening of the first sub-muffler 2 on the downstream side in the flow direction of exhaust gas is connected to the opening of the second sub-muffler 5 on the upstream side in the flow direction of exhaust gas. Further, a portion of the first sub-muffler 2 including the opening on the downstream side and a portion of the second sub-muffler 5 including the opening on the upstream side each have a double pipe structure.

[2. 1st sub muffler]
The first sub-muffler 2 has the functions of a muffler and an exhaust gas purifying device, and is configured, for example, as a tubular member extending along the axis 10 (see FIG. 1). Note that the axis 10 may be a straight line, or may have a bent or curved shape. Of course, the shape is not limited to this, and the first sub-muffler 2 may have a bent or curved shape, for example. The first sub-muffler 2 includes a first outer tube section 3, a first inner tube section 4, and a purification member 21.

[(1) First outer tube section]
The first outer tube portion 3 is, for example, a cylindrical portion, and a cross section (hereinafter simply referred to as a cross section) perpendicular to the axis 10 is circular (see FIG. 1). Further, the first outer tube section 3 includes an inlet section and a tube expansion section (not shown), a main body section 30, a tube contraction section 31, and an outlet section 32.

The inlet portion is a cylindrical portion that forms an inlet for exhaust gas to the first outer pipe portion 3 (in other words, the first sub-muffler 2), and is connected to an exhaust pipe adjacent to the upstream side of the first sub-muffler 2. Ru.
The expanded tube portion is a portion adjacent to the downstream side of the inlet portion, and has a shape in which the diameter of the cross section increases toward the downstream side.

The main body part 30 is a cylindrical part that is adjacent to the downstream side of the tube expansion part and in which a purifying member 21 for purifying exhaust gas is disposed. Note that the purifying member 21 may be configured, for example, as a catalyst that reforms or captures pollutants in exhaust gas by contacting with exhaust gas.

The tube contraction section 31 is adjacent to the main body section 30 on the downstream side, and has a shape in which the cross-sectional diameter decreases toward the downstream side.
The outlet portion 32 is a cylindrical portion adjacent to the downstream side of the tube contraction portion 31, and the opening on the downstream side of the outlet portion 32 passes through the first outer tube portion 3 (in other words, the first sub-muffler 2). A first outer tube opening 33 is formed as an outlet for the discharged exhaust gas. Note that, as an example, the outlet portion 32 may be formed by spinning.

[(2) First inner pipe section]
The first inner tube section 4 is arranged inside the region including the downstream end of the main body section 30 of the first outer tube section 3, the tube contraction section 31, and the outlet section 32 (see FIG. 1). . The first inner tube section 4 includes a wall section 40 and a straight section 42 . Note that the wall portion 40 and the straight portion 42 may be configured as an integral member or separate members.

The wall portion 40 is a circular plate-shaped portion with the axis 10 located at the center, and a flange-like connecting portion 41 is provided on the edge forming the outer periphery. The connecting portion 41 is joined to the inner circumferential surface of the main body portion 30 . Furthermore, a circular hole passing through the wall portion 40 is provided at the center of the wall portion 40 . Further, the wall portion 40 is provided so as to be orthogonal to the axis 10, and partitions the internal space of the main body portion 30 into an upstream side and a downstream side. An exhaust gas purifying member 21 is arranged in a space on the upstream side of the wall portion 40, and a muffling space 20 for suppressing muffler noise is formed on the downstream side. Note that a sound absorbing material such as glass wool may be arranged in the sound deadening space 20.

Further, the shape of the wall portion 40 can be determined as appropriate, and may be, for example, a substantially truncated conical shape that is not perpendicular to the axis 10 and protrudes downstream toward the center. When the wall portion 40 has such a shape, the exhaust gas that has passed through the purification member 21 easily flows downstream.

The straight portion 42 is a cylindrical portion that projects straight downstream along the axis 10 from the edge surrounding the central hole in the wall portion 40 . The straight part 42 forms a double pipe together with the first outer tube part 3, more specifically, the main body part 30, the tube contraction part 31, and the outlet part 32. The first outer tube section 3 and the straight section 42 are arranged so that their cross sections form concentric circles centered on the axis 10, and the straight section 42, the main body section 30, the tube contraction section 31, and the outlet section 32 In between, the above-mentioned silencing space 20 is formed so as to go around the straight part 42.

Further, in the vicinity of the first inner tube opening 43 located at the downstream end of the straight portion 42, there is a reduced portion where the diameter of the cross section of the straight portion 42 decreases (in other words, becomes thinner) toward the downstream side. 44 is formed. As an example, the reduced portion 44 has a tapered shape (in other words, a suction shape) inclined with respect to the axis 10 and is adjacent to the first inner tube opening 43 .

However, in addition to this, for example, the reduced portion 44 is provided at a position slightly spaced from the first inner tube opening 43 and extends straight between the reduced portion 44 and the first inner tube opening 43. A portion may be provided. That is, the downstream end of the straight portion 42 may become gradually thinner toward the downstream side. In this case, the reduced portion 44 may be provided perpendicularly to the axis 10. Further, in this embodiment, the reduced portion 44 extends linearly in a cross section parallel to the axis 10, but for example, the reduced portion 44 may have a curved shape in the cross section.

Note that the straight portion 42 may not have the reduced portion 44 and may extend straight to the downstream end. The downstream end of the straight portion 42 including the reduced portion 44 projects outward from the first outer tube opening 33 of the first outer tube portion 3 . In other words, the first inner tube opening 43 and the reduced portion 44, which are openings on the downstream side of the straight portion 42, are located outside the first outer tube opening 33.

Furthermore, at least one hole 45 is provided on the outer circumferential surface of the straight portion 42 . The hole portion 45 penetrates the straight portion 42 and communicates the silencing space 20 with the internal space of the straight portion 42 .

Therefore, the purified exhaust gas passes through the purifying member 21 housed in the main body part 30 and flows into the straight part 42 through the hole in the center of the wall part 40 . Then, the exhaust gas that has flowed into the straight portion 42 passes through the hole portion 45 of the straight portion 42, flows into the silencing space 20, and expands, thereby muffling the noise. Furthermore, if a sound absorbing material is placed in the sound deadening space 20, the sound absorbing material further muffles the sound.

[3. 2nd sub muffler]
The second sub-muffler 5 has a function as a muffler that uses sound wave interference to muffle sound (see FIG. 1). Specifically, the second sub-muffler 5 may perform noise reduction using Helmholtz resonance, or may perform noise reduction using side branches, for example. The second sub-muffler 5 includes a second outer tube section 6 and a second inner tube section 7 arranged to form a double pipe, and a holding member 51. For example, the second sub-muffler 5 may extend along the axis 10, or may have a bent or curved shape.

[(1) Second outer tube section and second inner tube section]
The second outer tube part 6 and the second inner tube part 7 each have a second outer tube opening 60 and a second inner tube opening 70, which are openings located on the upstream side (see FIG. 1). The second inner tube section 7 is located inside the second outer tube section 6, and the second outer tube section 6 and the second inner tube section 7 are arranged so that their cross sections form concentric circles centered on the axis 10. Placed. A silencing space 50 is formed between the second outer tube section 6 and the second inner tube section 7 so as to go around the second inner tube section 7.

Further, the upstream end of the second outer tube section 6 is located more upstream than the upstream end of the second inner tube section 7. That is, the second inner tube opening 70 is located inside the second outer tube section 6. Further, as an example, a portion of the second outer tube section 6 and the second inner tube section 7 including the upstream end extends along the axis 10. By way of example, the section extends straight along axis 10.

Further, a joint (not shown) is provided at the downstream end of the second outer tube section 6 and the second inner tube section 7, and the second outer tube section 6 and the second inner tube section 7 are connected to each other. are joined to each other at the parts. Moreover, at least one communication path that communicates the silencing space 50 and the internal space of the second inner tube section 7 is formed in the joint portion. Furthermore, the upstream end of the silencing space 50 is covered by a holding member 51, which will be described later.

Therefore, the exhaust gas flowing into the second sub-muffler 5 mainly passes through the second inner pipe opening 70 of the second inner pipe part 7 and flows down through the internal space 71 located inside the second inner pipe part 7. . Further, in the second sub-muffler 5, the sound waves generated by the exhaust gas flowing down the internal space 71 of the second inner pipe portion 7 enter the silencing space 50 via the communication path of the joint portion. Then, interference of sound waves occurs between the internal space 71 of the second inner pipe portion 7 and the muffling space 50, and sound muffling is performed.

Further, as an example, the diameter of the cross section of the second outer tube part 6 and the second inner tube part 7 other than the joint part is approximately constant, and the thickness of the sound deadening space 50 is It is substantially constant from the upstream end to the downstream end.

[(2) Holding member]
The holding member 51 is configured as a wire mesh, for example, and is located between a portion of the outer circumferential surface of the second inner tube section 7 adjacent to the second inner tube opening 70 and an inner circumferential surface of the second outer tube section 6. (See Figure 1).

More specifically, the holding member 51 is arranged so as to go around the second inner tube part 7. The upstream portion 52, which is a part of the holding member 51, is provided on the inner peripheral surface of the second outer tube portion 6 at a portion upstream of the second inner tube opening 70, and the upstream portion 52 is also provided on the inner peripheral surface of the second outer tube portion 6. Moreover, it is provided so that it may go around the 2nd inner tube opening 70. Further, as an example, the holding member 51 is provided at a position spaced apart from the second outer tube opening 60 of the second outer tube portion 6. Of course, the holding member 51 may be provided adjacent to the second outer tube opening 60 or may protrude from the second outer tube opening 60. Moreover, the holding member 51 may be provided without going around the second inner tube part 7.

Further, the holding member 51 is joined to the outer circumferential surface of the second inner tube part 7 by spot welding, for example, and the inner circumferential surface of the second outer tube part 6 is slidably attached to the holding member 51. are in contact with each other. That is, the holding member 51 provides a sliding structure for absorbing the difference in thermal expansion between the second outer tube section 6 and the second inner tube section 7.

Note that, on the contrary, the holding member 51 is joined to the inner circumferential surface of the second outer tube part 6, and the outer circumferential surface of the second inner tube part 7 is slidable with respect to the holding member 51. It is okay to be in contact with each other. In this case, it is preferable to form a reduced portion at the upstream end of the second inner tube portion 7, which becomes thinner toward the upstream side. This makes it easier to insert the upstream end of the second inner tube section 7 inside the holding member 51, and it becomes easier to assemble the second inner tube section 7 inside the second outer tube section 6.

[4. Connection of first and second sub-mufflers]
The first outer pipe opening 33 in the first outer pipe part 3 of the first sub-muffler 2 is connected to the second outer pipe opening 60 of the second outer pipe part 6 of the second sub-muffler 5 (see FIG. 1). Specifically, the end portion of the second outer tube portion 6 including the second outer tube opening 60 is inserted into the first outer tube opening 33 of the first outer tube portion 3 . Then, the edge surrounding the first outer tube opening 33 in the first outer tube section 3 is joined to the second outer tube section 6 by, for example, welding.

Further, the first inner pipe opening 43 in the first inner pipe part 4 of the first sub-muffler 2 faces the second inner pipe opening 70 in the second inner pipe part 7 of the second sub-muffler 5. Then, the end portion of the first inner tube portion 4 that includes the first inner tube opening 43 is inserted into the upstream portion 52 of the holding member 51 of the second sub-muffler 5 . In other words, the portion of the first inner tube portion 4 that protrudes from the first outer tube opening 33 is inserted into the upstream portion 52 . The upstream portion 52 is in a state in which it goes around the reduced portion 44 of the first inner tube portion 4 and a portion adjacent to the reduced portion 44 .

Note that, as shown in FIG. 1, a gap may be formed between the first inner tube opening 43 and the second inner tube opening 70. Further, for example, the first inner tube opening 43 and the second inner tube opening 70 may be in contact with each other, or the first inner tube opening 43 may be located inside the second inner tube portion 7.

The upstream portion 52 of the holding member 51 is located between the outer circumferential surface of the first inner tube section 4 and the inner circumferential surface of the second outer tube section 6 of the second sub-muffler 5. The first inner tube portion 4 is not joined to the upstream portion 52, and the outer circumferential surface of the first inner tube portion 4 is slidably in contact with the upstream portion 52. Therefore, the holding member 51 of the second sub-muffler 5 provides a sliding structure for absorbing the difference in thermal expansion between the first outer tube section 3 and the first inner tube section 4 in the first sub-muffler 2.

[Second embodiment]
[5. overview]
The exhaust system 1 of the second embodiment includes first and second sub-mufflers 2 and 5 similar to those of the first embodiment (see FIG. 2). However, the second embodiment differs from the first embodiment in that the first sub-muffler 2 is provided with a holding member 22 for providing a sliding structure. The configuration of the exhaust system 1 according to the second embodiment will be described below, focusing on the differences from the first embodiment.

[6. 1st sub muffler]
The first sub-muffler 2 of the second embodiment differs from the first embodiment in the configuration of the straight portion 42 of the first inner tube portion 4 and the provision of a holding member 22 (see FIG. 2).

In the second embodiment, the downstream end of the straight portion 42 is not provided with a reduced portion. Further, the first inner tube opening 43 of the straight portion 42 is arranged inside the first outer tube opening 33 of the first outer tube portion 3. In other words, the downstream end of the outlet section 32 of the first outer tube section 3 is located downstream of the first inner tube opening 43.

As in the first embodiment, the holding member 22 is made of wire mesh, for example, and includes a portion adjacent to the first inner tube opening 43 on the outer circumferential surface of the straight portion 42 and an inner circumferential surface of the outlet portion 32. is established between.

More specifically, the holding member 22 is arranged so as to go around the straight portion 42 . Further, the downstream portion 23, which is a part of the holding member 22, is provided at a portion downstream of the first inner tube opening 43 on the inner circumferential surface of the outlet portion 32, and the downstream portion 23 is also provided at a portion downstream of the first inner tube opening 43. 1 so as to go around the inner tube opening 43. Further, as an example, the holding member 22 is provided at a position spaced apart from the first outer tube opening 33 in the outlet portion 32. Of course, the holding member 22 may be provided adjacent to the first outer tube opening 33 or may protrude from the first outer tube opening 33. Moreover, the holding member 22 may be provided without going around the straight part 42.

Further, the holding member 22 is joined to the outer circumferential surface of the straight portion 42 by spot welding, for example, and the inner circumferential surface of the outlet portion 32 is slidably in contact with the holding member 22. That is, the holding member 22 provides a sliding structure for absorbing the difference in thermal expansion between the first outer tube section 3 and the first inner tube section 4. Note that, on the contrary, the holding member 22 may be joined to the inner circumferential surface of the outlet portion 32, and the outer circumferential surface of the straight portion 42 may be slidably in contact with the holding member 22. .

[7. 2nd sub muffler]
The second sub-muffler 5 of the second embodiment differs from the first embodiment in the configuration of the second inner pipe portion 7 and in that no holding member is provided (see FIG. 2).

In the vicinity of the second inner tube opening 70 of the second inner tube section 7, a reduced portion 72 is formed in which the diameter of the cross section of the second inner tube section 7 decreases toward the upstream side, similarly to the first embodiment. has been done. As an example, the reduced portion 72 has a tapered shape and is adjacent to the second inner tube opening 70, similar to the first embodiment.

However, in addition to this, as described in the first embodiment, the reduced portion 72 may be provided, for example, at a position slightly spaced from the second inner tube opening 70, or may be provided along the axis 10. They may be provided perpendicularly to each other. Further, the reduced portion 44 may have a curved shape in a cross section parallel to the axis 10.

Note that the second inner tube portion 7 may not have the reduced portion 72 and may extend straight to the upstream end. The upstream end of the second inner tube section 7 including the reduced portion 72 projects outward from the second outer tube opening 60 of the second outer tube section 6 . In other words, the second inner tube opening 70 and the reduced portion 72 are located outside the second outer tube opening 60.

Further, a gap similar to the first embodiment is formed between the inner circumferential surface of the second outer tube section 6 and the outer circumferential surface of the second inner tube section 7, and the holding member is not inserted into the gap. Not placed.
[7. Connection of first and second sub-mufflers]
Also in the second embodiment, the first outer pipe opening 33 in the first outer pipe part 3 of the first sub-muffler 2 is connected to the second outer pipe opening 60 of the second outer pipe part 6 of the second sub-muffler 5 ( (see Figure 2). However, in the second embodiment, the end portion of the first outer tube section 3 that includes the first outer tube opening 33 is inserted into the second outer tube opening 60 of the second outer tube section 6 . Then, the edge surrounding the second outer tube opening 60 in the second outer tube section 6 is joined to the first outer tube section 3 by, for example, welding.

Further, the first inner pipe opening 43 in the first inner pipe part 4 of the first sub-muffler 2 faces the second inner pipe opening 70 in the second inner pipe part 7 of the second sub-muffler 5. Then, the end portion of the second inner tube portion 7 including the second inner tube opening 70 is inserted into the downstream portion 23 of the holding member 22 of the first sub-muffler 2 . In other words, the portion of the second inner tube portion 7 that protrudes from the second outer tube opening 60 is inserted into the downstream portion 23 . The downstream portion 23 is in a state in which it goes around the reduced portion 72 of the second inner tube portion 7 and a portion adjacent to the reduced portion 72.

Note that, as shown in FIG. 2, a gap may be formed between the first inner tube opening 43 and the second inner tube opening 70. Further, for example, the first inner tube opening 43 and the second inner tube opening 70 may be in contact with each other, or the first inner tube opening 43 may be located inside the second inner tube portion 7.

The downstream portion 23 of the holding member 22 is located between the outer circumferential surface of the second inner pipe section 7 and the inner circumferential surface of the outlet section 32 of the first sub-muffler 2. The second inner tube portion 7 is not joined to the downstream portion 23, and the outer circumferential surface of the second inner tube portion 7 is in slidable contact with the downstream portion 23. Therefore, the downstream portion 23 of the first sub-muffler 2 provides a sliding structure for absorbing the difference in thermal expansion between the second outer tube section 6 and the second inner tube section 7 in the second sub-muffler 5.

[8. effect]
(1) According to the above embodiment, the holding members 22 and 55 provided on one of the first and second sub-mufflers 2 and 5 prevent the difference in thermal expansion of the double pipes between the first and second sub-mufflers 2 and 5. It can be absorbed. Therefore, the number of parts in the exhaust system 1 can be reduced, and the manufacturing cost of the exhaust system 1 can be reduced.

(2) Furthermore, in the above embodiment, a gap exists between the first inner tube opening 43 and the second inner tube opening 70, which prevents the heat of the first and second inner tube portions 4 and 7. Can absorb stretch. Further, holding members 22 and 55 are provided so as to surround the space between the first inner tube opening 43 and the second inner tube opening 70. Therefore, radiation of heat from the connecting portion of the first or second sub-mufflers 2 and 5 can be suppressed.

(3) Furthermore, the first inner pipe portion 4 of the first sub-muffler 2 of the first embodiment is provided with a reduced portion 44. Therefore, when connecting the first and second sub-mufflers 2 and 5, it becomes easier to insert the first inner pipe portion 4 into the holding member 51 of the second sub-muffler 5. Also in the second embodiment, the second inner pipe portion 7 of the second sub-muffler 5 is provided with a reduced portion 72 . Therefore, when connecting the first and second sub-mufflers 2 and 5, it becomes easier to insert the second inner pipe portion 7 into the holding member 22 of the first sub-muffler 2. Therefore, manufacturing of the exhaust system 1 becomes easy.

(4) Furthermore, since the first sub-muffler 2 of the first embodiment is not provided with a holding member, the silencing space 20 can be made wider. Therefore, the noise reduction effect of the first sub-muffler 2 is improved.

(5) Furthermore, in the first sub-muffler 2 of the first and second embodiments, the first inner pipe portion 4 is provided on the downstream side of the purifying member 21. A silencing space 20 is provided between the first inner tube section 4 and the first outer tube section 3. Therefore, the space for arranging members used for purifying exhaust gas and muffling noise and the number of parts can be reduced.

[9. Other embodiments]
(1) The present disclosure is applicable not only to the exhaust system 1 having a sub-muffler, but also to exhaust systems having combinations of various exhaust devices connected by portions having a double pipe structure. Specifically, the first and second sub-mufflers 2 and 5 of the above embodiment are configured as an exhaust device, such as a main muffler, an exhaust heat recovery device, or an exhaust gas purification device, which are connected with the same configuration, respectively. It's okay if it's done.

(2) The first or second sub-muffler 2, 5 in the exhaust system 1 in the embodiment described above may be distributed individually on the market. Even in such a case, the same effect can be obtained by using it in combination with an exhaust device having a corresponding configuration.

(3) A plurality of functions of one component in the above embodiment may be realized by a plurality of components, and a function of one component may be realized by a plurality of components. . Further, a plurality of functions possessed by a plurality of constituent elements may be realized by one constituent element, or one function realized by a plurality of constituent elements may be realized by one constituent element. Further, a part of the configuration of the above embodiment may be omitted. Further, at least a part of the configuration of the above embodiment may be added to or replaced with the configuration of other embodiments.

[10. Word correspondence]
The first sub-muffler 2 of the first embodiment and the second sub-muffler 5 of the second embodiment correspond to an example of a first exhaust device. The second sub-muffler 5 of the first embodiment and the first sub-muffler 2 of the second embodiment correspond to an example of a second exhaust device. The first sub-muffler 2 of the first and second embodiments corresponds to an example of an upstream exhaust device.

DESCRIPTION OF SYMBOLS 1... Exhaust system, 2... First sub-muffler, 20... Sound deadening space, 22... Holding member, 23... Downstream part, 3... First outer pipe part, 33... First outer pipe opening, 4... First inner pipe part , 42... Straight part, 43... First inner pipe opening, 44... Reducing part, 5... Second sub-muffler, 50... Sound deadening space, 51... Holding member, 52... Upstream part, 6... Second outer pipe part, 60 ...Second outer tube opening, 7...Second inner tube portion, 70...Second inner tube opening, 71...Inner space, 72...Reduction portion.

Claims (7)

An exhaust system comprising first and second exhaust devices configured to form a flow path for exhaust gas in a vehicle, the exhaust system comprising:
The first exhaust device includes:
a first outer tube portion having a first outer tube opening configured to be connected to a second outer tube opening of the second exhaust device;
a first inner tube part located inside the first outer tube part, provided so as to protrude outward from the first outer tube opening, and having a first inner tube opening;
The second exhaust device includes:
a second outer tube portion having the second outer tube opening and configured to be joined to the first outer tube portion;
a second inner tube part having a second inner tube opening located inside the second outer tube opening and located inside the second outer tube part;
A portion provided between the inner circumferential surface of the second outer tube portion and a portion of the outer circumferential surface of the second inner tube portion adjacent to the second inner tube opening, the second outer tube portion and a holding member that is a slidable portion with respect to one of the inner circumferential surface of the inner circumferential surface and the outer circumferential surface of the second inner tube part,
The holding member is configured to slidably abut against the outer circumferential surface of the first inner pipe section. The exhaust system. The exhaust system according to claim 1,
An exhaust system, wherein a contracting part that becomes thinner toward the first inner pipe opening is provided near the first inner pipe opening in the first inner pipe part. The exhaust system according to claim 1 or claim 2,
At least one of the first and second exhaust devices is configured to muffle noise by causing exhaust gas to flow into a space between the inner tube section and the outer tube section. 4. The exhaust system according to claim 3,
Of the first and second exhaust devices, the one located on the upstream side in the flow direction of exhaust gas is an upstream exhaust device,
The upstream exhaust device is configured to muffle noise by causing exhaust gas to flow into a space between the inner tube portion and the outer tube portion,
The upstream exhaust device further includes a space in which a purification member for purifying exhaust gas is disposed,
The inner pipe part of the upstream exhaust device is located downstream in the flow direction of exhaust gas with respect to the space in which the purification member is arranged. Exhaust system. The exhaust system according to any one of claims 1 to 4,
At least one of the first and second exhaust devices is configured to perform noise reduction using sound wave interference using a space between the inner tube section and the outer tube section. A first exhaust device configured to form an exhaust gas flow path in a vehicle together with a second exhaust device including a second outer tube portion and a second inner tube portion located inside the second outer tube portion. And,
a first outer tube portion having a first outer tube opening configured to be connected to a second outer tube opening of the second outer tube portion and configured to be joined to the second outer tube portion;
a first inner tube part located inside the first outer tube part, provided so as to protrude outward from the first outer tube opening, and having a first inner tube opening;
The first inner tube portion is such that when the first outer tube opening is connected to the second outer tube opening, the outer peripheral surface of the first inner tube portion is connected to the second outer tube portion of the second exhaust device. The first exhaust device is configured to slidably abut against a holding member provided between the first exhaust device and the second inner tube portion. A second exhaust device configured to form an exhaust gas flow path in a vehicle together with a first exhaust device including a first outer tube portion and a first inner tube portion located inside the first outer tube portion. And,
a second outer tube section having a second outer tube opening configured to be connected to the first outer tube opening of the first outer tube section, and configured to be joined to the first outer tube section;
a second inner tube part having a second inner tube opening located inside the second outer tube opening and located inside the second outer tube part;
A portion provided between the inner circumferential surface of the second outer tube portion and a portion of the outer circumferential surface of the second inner tube portion adjacent to the second inner tube opening, the second outer tube portion and a holding member that is a slidable portion with respect to one of the inner circumferential surface of the inner circumferential surface and the outer circumferential surface of the second inner tube part,
The holding member is configured to slidably abut against the outer peripheral surface of the first inner tube portion when the second outer tube opening is connected to the first outer tube opening.

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