JP2022151013A - Silencer - Google Patents

Abstract

To provide a technique which suppresses occurrence of stress caused by deformation due to the heat in the periphery of a communication hole provided in an inner pipe.SOLUTION: A silencer includes an inner pipe, an enclosure member, and a passage formation part. The inner pipe has a communication hole for communicating the inside and outside of the inner pipe. The enclosure member is arranged so as to surround an outer periphery of the inner pipe. The passage formation part is arranged in a space formed between the inner pipe and the enclosure member, and forms a passage for connecting the communication hole and an opening part opening to the space. Also, the passage formation part is fixed to an outer peripheral surface of the inner pipe by a plurality of weld parts which are portions where the passage formation part and the inner pipe are welded. A region that spreads in a circumferential direction of the inner pipe in the range in which the communication hole is provided with regard to a direction along a central axis of the inner pipe is a non-weld region where the plurality of weld parts are not provided.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to silencers.

In Patent Document 1, a communication hole is formed in a resonance chamber formed by an inner pipe having a communication hole, an outer pipe in which the inner pipe is inserted, and a space between the inner pipe and the outer pipe. A muffler is disclosed that includes a cover that is fixed to the outer peripheral surface of the inner pipe by welding so as to cover the inner pipe.

Utility Model Registration No. 3075992

By the way, in the muffler as described above, since high-temperature exhaust gas passes through the inner pipe, a temperature difference occurs between the inner pipe and the cover. As a result, the inner tube becomes hotter than the cover and expands more easily than the cover. Furthermore, the area around the communication hole of the inner pipe provided with the communication hole as described above is also likely to be deformed by heat. Thus, when the area around the communication hole is deformed by the heat of the exhaust gas, there is a problem that the stress applied to the welded portion between the inner pipe and the cover around the communication hole increases.

An object of one aspect of the present disclosure is to provide a technique for suppressing the generation of stress due to thermal deformation around a communication hole provided in an inner pipe.

One aspect of the present disclosure is a muffler that includes an inner tube, an outer shell member, and a passageway formation. The inner pipe has a communication hole through which the exhaust gas passes and communicates between the inside and the outside of the inner pipe. The outer shell member is arranged so as to surround the outer periphery of the inner tube. The passage forming portion is arranged in the space formed between the inner tube and the outer shell member, and forms a passage connecting the communication hole and the opening opening to the space. Moreover, the passage forming portion is fixed to the outer peripheral surface of the inner pipe by a plurality of welded portions, which are portions where the passage forming portion and the inner pipe are welded. A region extending in the circumferential direction of the inner pipe in the range in which the communication hole is provided in the direction along the central axis of the inner pipe is a non-welded region in which a plurality of welded portions are not provided.

In such a configuration, a plurality of welds are not provided in the non-weld area. The non-welded region is a region extending in the circumferential direction of the inner pipe within the range where the communication holes are provided in the direction along the central axis of the inner pipe. Here, the periphery of the communication hole of the inner pipe is more likely to be deformed by heat in the circumferential direction of the inner pipe than in the direction along the central axis of the inner pipe. For this reason, by making the range in which the communicating hole is provided in the direction along the central axis of the inner pipe a non-welded region where the welded portion is not provided, deformation due to heat around the communicating hole provided in the inner pipe It is possible to suppress the generation of stress.

In one aspect of the present disclosure, at least one of the plurality of welded portions may be arranged at a position on the opposite side of the opening along the central axis with respect to the communicating hole. In such a configuration, the passage forming portion is fixed to the inner pipe by the welding portion at a position opposite to the opening portion along the central axis of the inner pipe with the communicating hole as a reference. Therefore, it is possible to suppress the generation of contact noise (so-called chattering noise) caused by contact between the inner tube and the passage forming portion due to vibration.

In one aspect of the present disclosure, the passage-forming portion has a length in a direction along the central axis of the inner pipe and is arranged on the outer peripheral surface so as to cover a portion of the inner pipe so as to have an opening. , a passage connecting the communication hole and the opening may be formed. The plurality of welded portions are spaced apart from each other along the contact end portion having a length in the direction along the central axis of the inner pipe among the end portions contacting the outer peripheral surface of the passage forming portion. may be placed side by side. The weld area of the first weld located closest to the opening among the plurality of welds provided at the contact end is larger than the weld area of each of the welds other than the first weld among the plurality of welds. can also be large. According to such a configuration, since the passage-forming portion and the inner pipe are fixed by the plurality of welded portions in the direction along the central axis of the inner pipe, the fixing strength of the passage-forming portion to the inner pipe can be improved. can. Further, the passage forming portion is fixed to the inner pipe at the opening side closest to the passage forming portion by the first welding portion having a larger welding area than the other welding portions. For this reason, for example, compared to the case where the most opening side of the passage forming portion is fixed with a welding area of the same size as the other welding portions, the opening side of the passage forming portion may be deformed as the inner pipe expands due to heat. can be suppressed from being deformed by heat.

It is a typical sectional view of a silencer. FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1; FIG. 2 is an end view taken along line III-III of FIG. 1; FIG. 4 is a diagram schematically showing deformation around a communication hole of an inner tube due to expansion of the inner tube due to heat. FIG. 4 is a cross-sectional view schematically showing deformation of the inner pipe around the communication hole and deformation of the cover due to expansion of the inner pipe due to heat. FIG. 5 is a side view schematically showing deformation of the cover due to thermal expansion of the inner tube. 1 is a schematic cross-sectional view of a muffler with a shell; FIG. FIG. 4 is a top view schematically showing a configuration in which a passage connecting a communication hole and an opening is formed by a pipe; FIG. 4 is a side view schematically showing a configuration in which a passage connecting a communicating hole and an opening is formed by a pipe;

Exemplary embodiments of the present disclosure are described below with reference to the drawings.
[1. Constitution]
A muffler 100 shown in FIG. 1 is a device for reducing exhaust noise used in an exhaust system forming an exhaust gas flow path of an internal combustion engine. The muffler 100 includes an inner tube 1 , an outer tube 2 , a first end plate 21 , a second end plate 22 and a cover 3 . In this embodiment, the muffler 100 has a double-tube structure. The muffler 100 exerts a muffling effect by the resonance chamber 23 formed by the space between the inner tube 1 and the outer tube 2 . The space between the inner tube 1 and the outer tube 2 may contain a sound absorbing material or the like.

The internal combustion engine to which the exhaust system is applied is not particularly limited, but includes those used for driving or generating power in transportation equipment such as automobiles, railroads, ships, and construction machinery, and power generation facilities.

The inner pipe 1 is a metal pipe through which the exhaust gas passes. Specifically, the exhaust gas is introduced into the inner tube 1 through one of the opening on the first end 11 side and the opening on the second end 12 side, and is discharged from the opening on the opposite side. In this embodiment, the inner pipe 1 is a straight pipe with a constant diameter.

The inner tube 1 has a communication hole 13 that communicates the inside and the outside of the inner tube 1 . In this embodiment, one communication hole 13 is provided near the second end 12 of the inner pipe 1 . As shown in FIG. 2, in this embodiment, the communication hole 13 is formed in a perfect circle.

The outer tube 2 is a metal pipe arranged outside the inner tube 1 so as to surround the outer peripheral surface of the inner tube 1 . As shown in FIG. 3, the outer tube 2 is formed in a cylindrical shape with a substantially elliptical cross section perpendicular to the central axis A of the inner tube 1 . The inner diameter of the outer tube 2 is larger than the outer diameter of the inner tube 1 . The central axis of the outer tube 2 is arranged so as to coincide with the central axis A. As shown in FIG. Note that these central axes do not necessarily have to coincide.

As shown in FIG. 1, the first end plate 21 is a lid member provided to close the end of the outer tube 2 on the first end 11 side of the inner tube 1. The second end plate 22 is It is a cover member provided so as to close the end of the outer tube 2 on the second end 12 side. The first end 11 of the inner tube 1 passes through a through hole provided in the first end plate 21 and is fixed to the first end plate 21 . Also, the second end portion 12 of the inner tube 1 passes through a through hole provided in the second end plate 22 and is fixed to the second end plate 22 . The open side end portions of the outer tube 2 may be directly fixed to the outer peripheral surfaces of the first end portion 11 of the inner tube 1 and the second end portion 12 of the inner tube 1 by welding or the like.

The cover 3 is a curved plate-like member having a length along the central axis A. As shown in FIG. As shown in FIG. 3, the cover 3 is curved so that the cross section perpendicular to the central axis A has a substantially semicircular shape. Returning to FIG. 1 , the cover 3 is arranged inside the resonance chamber 23 so as to cover the communication hole 13 . Specifically, the cover 3 is arranged on the outer peripheral surface of the inner tube 1 so as to cover a part of the inner tube 1 so as to have an opening 311 . The opening 311 is a portion of the cover 3 that opens to the resonance chamber 23 . Thus, by covering a part of the inner tube 1 so as to cover the communicating hole 13 and disposing the cover 3 on the outer peripheral surface of the inner tube 1, a passage connecting the communicating hole 13 and the opening 311 is formed. be done. This passage functions as a resonance tube.

As shown in FIG. 2, the cover 3 has a first end 31 , a second end 32 , a third end 33 and a fourth end 34 . The first end 31 and the second end 32 are ends on both sides of the cover 3 in the direction along the central axis A, and the first end 31 is positioned on the first end 11 side of the inner tube 1, The second end 32 is located on the second end 12 side of the inner tube 1 . The third end portion 33 and the fourth end portion 34 are end portions on both sides of the cover 3 in a direction perpendicular to the central axis A, and end portions of the cover 3 having a length in a direction along the central axis A. The cover 3 contacts the outer peripheral surface of the inner tube 1 at the second end 32 , the third end 33 and the fourth end 34 . As a result, as shown in FIG. 1, the first end 31 is opened to have an opening 311, and the second end 32 is closed. In addition, the second end portion 32 of the cover 3 has a shape that closes on the outer peripheral surface of the inner pipe 1 so as to decrease in diameter toward the central axis A while having a curve. The second end portion 32, the third end portion 33 and the fourth end portion 34 are flange-shaped so as to come into surface contact with the outer peripheral surface of the inner pipe 1, as shown in FIG.

As shown in FIG. 2, the cover 3 is fixed to the outer peripheral surface of the inner tube 1 by a plurality of welded portions 41 to 45, which are portions where the cover 3 and the inner tube 1 are welded. Specifically, the plurality of welds 41-44 are spaced apart from each other along the third and fourth ends 33 and 34 of the cover 3. is placed in In addition, the welded portion 45, which is one of the plurality of welded portions 41 to 45, is positioned at the second end portion 32 of the cover 3 on the opposite side of the opening 311 along the central axis A with respect to the communication hole 13. placed in

In this embodiment, the plurality of welds 41 to 45 includes two first welds 41, two second welds 42, two third welds 43, two fourth welds 44, And one fifth welded portion 45 is provided. From the first end 31 side of the cover 3, the first welded portion 41, the second welded portion 42, the third welded portion 43, and the fourth welded portion 44 are connected to the third end 33 and the fourth end of the cover 3, respectively. They are spaced apart from each other along the central axis A at the portions 34 . Also, the fifth welded portion 45 is provided near the center of the second end portion 32 of the cover 3 .

Specifically, the first welded portion 41, the second welded portion 42, the third welded portion 43, and the fourth welded portion 44 are located in a region closer to the first end portion 31 than the communication hole 13 in the direction along the central axis A. , and the fifth welded portion 45 is provided in a region closer to the second end portion 32 than the communication hole 13 in the direction along the central axis A. As shown in FIG. That is, in the present embodiment, a plurality of welded portions 41 to 45 are provided in the non-welded region R, which is a region extending in the circumferential direction of the inner pipe 1 within the range where the communication hole 13 is provided in the direction along the central axis A. not The length of the non-welding region R in the direction along the central axis A is at least the same as the length of the longest portion of the communicating hole 13 in the direction along the central axis A. In this embodiment, the length of the non-welding region R in the direction along the central axis A is at least the same length as the length of the diameter of the communication hole 13 . In addition, in the direction along the central axis A, there may be another region having no welded portion. Further, in addition to the non-welding region R, there may be auxiliary regions on both sides of the non-welding region R in the direction along the central axis A, which extend in the circumferential direction of the inner pipe 1 and are not provided with welded portions. For example, the length of the auxiliary region in the direction along the central axis A may be 1/3 of the diameter of the communication hole 13 . In this way, by widening the width of the region where the welded portion is not provided to the outside of the communication hole 13, it is possible to significantly suppress the generation of stress due to deformation due to heat around the communication hole 13 provided in the inner pipe 1. .

The welding areas of the first welds 41 located closest to the opening 311 provided at the third end 33 and the fourth end 34 are the second welds 42, the third welds 43, and the fourth welds. 44 and the welding area of the fifth welding portion 45. Specifically, when the length of each welded portion 41 to 45 in the direction perpendicular to the central axis A is constant, the length of the first welded portion 41 in the direction along the central axis A is the same as that of the second welded portion. 42 , the third welded portion 43 , and the fourth welded portion 44 in the direction along the central axis A, and the fifth welded portion 45 in the direction along the second end portion 32 . It is preferable to provide the fourth welded portion 44 at a position in contact with the non-welded region R as much as possible, and to shorten the distance between the fourth welded portion 44 and the fifth welded portion 45 as much as possible.

[2. effect]
According to the embodiment detailed above, the following effects are obtained.
(2a) In this embodiment, the cover 3 is fixed to the outer peripheral surface of the inner tube 1 by a plurality of welded portions 41 to 45 provided in regions other than the non-welded region R with respect to the direction along the central axis A. That is, the non-welding region R is not provided with the plurality of welded portions 41-45. In this way, by setting the range in which the communication hole 13 is provided in the direction along the central axis A of the inner pipe 1 as the non-welded region R in which the welded portion is not provided, the area around the communication hole 13 provided in the inner pipe 1 is It is possible to suppress the generation of stress caused by deformation due to heat.

In the configuration of the muffler 100 as described above, when the inner tube 1 expands due to heat, the periphery of the communication hole 13 of the inner tube 1 is also easily deformed due to heat. Specifically, as shown in FIGS. 4 and 5, the periphery of the communication hole 13 of the inner tube 1 is deformed more in the circumferential direction of the inner tube 1 than in the direction along the central axis A of the inner tube 1 due to heat. Cheap. In the case of the perfect circular communicating hole 13 as in the present embodiment, the diameter of the inner tube 1 in the circumferential direction is longer than the diameter in the direction along the central axis A of the inner tube 1, and is substantially elliptical. transform to become In addition, in FIG. 4, for convenience of explanation, the thermal deformation of the communication hole 13 is shown larger than the actual deformation. As described above, due to the thermal deformation of the communication hole 13 , a large stress that pulls the inner pipe 1 in the circumferential direction is applied to the area around the communication hole 13 of the inner pipe 1 .

For example, if the inner pipe 1 has a welded portion in the range where the communication hole 13 is provided in the direction along the central axis A, the welded portion is subjected to high stress, cracks occur in the welded portion, and the inner pipe 1 The fixing strength of the cover 3 with respect to may be lowered. On the other hand, in the present embodiment, the non-welding region R extending in the circumferential direction of the inner pipe 1 is provided in the range in which the communication hole 13 is provided in the direction along the central axis A of the inner pipe 1. It is possible to suppress the occurrence of stress due to deformation due to heat around the communicating hole 13. As a result, deterioration in fixing strength of the cover 3 to the inner pipe 1 can be suppressed.

In addition, in order to satisfy the fixing strength of the cover 3 to the inner pipe 1, the fixing strength of the cover 3 to the inner pipe 1 is improved while suppressing the cost, compared with, for example, a configuration in which the length of the welded portion is extended. can be made

(2b) In the present embodiment, the position opposite to the opening 311 of the cover 3 along the central axis A of the inner tube 1 with the communicating hole 13 as a reference, specifically the second end 32 of the cover 3. , and is fixed to the inner pipe 1 by means of fifth welds 45 . The fifth welded portion 45 provided at the second end portion 32 of the cover 3 is close to the communication hole 13 but is located on the side along the central axis A of the inner pipe 1 where thermal deformation of the inner pipe 1 is small with respect to the communication hole 13 . Therefore, it is less likely to be affected by stress caused by deformation due to heat around the communication hole 13 . Therefore, it is possible to suppress the generation of contact noise (so-called chattering noise) caused by the contact between the inner tube 1 and the cover 3 due to vibration, while suppressing the generation of stress due to deformation due to heat around the communication hole 13 . can be done. Further, by providing the fourth welded portion 44 at a position that is in contact with the non-welded region R as much as possible and shortening the distance between the fourth welded portion 44 and the fifth welded portion 45 as much as possible, the cover 3 is firmly fixed to the inner pipe 1. This makes it possible to further suppress the generation of the above-described contact noise.

(2c) In the configuration of the muffler 100 as described above, the inner pipe 1 through which high-temperature exhaust gas passes becomes hotter than the cover 3 and expands more easily than the cover 3 . Therefore, as shown in FIG. 6, the first end portion 31 and the second end portion 32 of the cover 3 warp upward due to the difference in thermal expansion of the inner tube 1 and the cover 3 in the direction along the central axis A. Easy to deform as it rises. In particular, the first end portion 31 having the opening 311 is likely to be subjected to a greater force that warps upward. In this embodiment, the second welded portion 42, the third welded portion 43, the fourth welded portion 44, and the fifth welded portion 42, which are provided at the second end portion 32, the third end portion 33, and the fourth end portion 34 of the cover 3, respectively. The cover 3 closest to the opening 311 is fixed to the inner tube 1 by the first welded portion 41 having a larger welding area than the welded portion 45 . For this reason, for example, when the first welded portion 41 of the cover 3 is fixed with the same welding area as the second welded portion 42, the third welded portion 43, the fourth welded portion 44, and the fifth welded portion 45, In comparison, it is possible to prevent the first end portion 31 side of the cover 3 from being deformed by heat due to the thermal expansion of the inner tube 1 . Further, the first welded portion 41 on the first end portion 31 side of the cover 3 and the fifth welded portion 45 on the second end portion 32 of the cover 3 provide a Deformation of the cover 3 in the along direction can be suppressed.

In the embodiment, the outer tube 2 corresponds to an example of the shell member, the cover 3 corresponds to an example of the passage forming portion, and the third end portion 33 and the fourth end portion 34 correspond to an example of the contact end portion. do.
[3. Other embodiments]
Although the embodiments of the present disclosure have been described above, it is needless to say that the present disclosure is not limited to the above embodiments and can take various forms.

(3a) The cross-sectional shape of the cover 3 perpendicular to the central axis A is not limited to a substantially semicircular shape, and may be a polygonal shape or the like.
(3b) The shape of the communication hole 13 is not limited to a perfect circle, and may be elliptical, polygonal, or the like.

(3c) In the above embodiment, the plurality of welded portions 41 to 45 includes two first welded portions 41, two second welded portions 42, two third welded portions 43, and a fourth welded portion 44. Although the configuration in which two and one fifth welding portion 45 are provided has been exemplified, the number of welding portions provided is not limited to this.

(3d) In the above embodiment, the muffler 100 having a double-tube structure composed of the inner tube 1 and the outer tube 2 was illustrated, but the configuration of the muffler is not limited to this. For example, like a muffler 100a shown in FIG. 7, a configuration in which a cover 3a arranged to cover an inner tube 1a and a communication hole 13a provided in the inner tube 1a is provided in an internal space formed by a shell 2a. may be In such a configuration, the resonance chamber is formed by the first end plate 21a, the second end plate 22a, the shell 2a, and the separator 5, and the resonance tube is formed by the cover 3a and the inner tube 1a. Although the example shown in FIG. 7 illustrates a configuration having two inner pipes 1a that are an inlet pipe and an outlet pipe, the configuration includes one inner pipe 1a that forms either one of the inlet pipe and the outlet pipe. good too. Even with such a configuration of the muffler 100a, the inner tube 1a and the cover 3a are welded so as to provide the non-welded region R, so that the same effect as (2a) of the above-described embodiment can be obtained. can.

(3e) In the above embodiment, the cover 3 forms the passage connecting the communication hole 13 and the opening 311, but the structure in which the passage connecting the communication hole and the opening is formed is limited to this. not to be For example, as shown in FIGS. 8 and 9, a passage connecting the communication hole 13 and the opening 311b may be formed by a metal pipe 3b. The pipe 3b has an L-shaped bend. The pipe 3b contacts the inner pipe 1 so that the second end 32b opposite to the first end 31b having the opening 311b covers the communication hole 13 provided in the inner pipe 1. As shown in FIG. The second end 32b has a larger diameter than the first end 31b. With respect to the direction along the central axis A of the inner tube 1 , the second end 32 b is fixed to the outer peripheral surface of the inner tube 1 by providing two welded portions 51 in regions other than the non-welded region R. The two welded portions 51 are provided side by side along the central axis A of the inner pipe 1 so as to sandwich the communicating hole 13 . Even in a configuration including such a pipe 3b, the inner tube 1 and the pipe 3b are welded so as to provide the non-welded region R, thereby obtaining the same effect as (2a) of the above-described embodiment. can.

(3f) The function of one component in the above embodiments may be distributed as multiple components, or the functions of multiple components may be integrated into one component. Also, part of the configuration of the above embodiment may be omitted. Also, at least a part of the configuration of the above embodiment may be added, replaced, etc. with respect to the configuration of the other above embodiment. It should be noted that all aspects included in the technical idea specified by the wording in the claims are embodiments of the present disclosure.

DESCRIPTION OF SYMBOLS 1, 1a... Inner tube, 2... Outer tube, 2a... Shell, 3, 3a... Cover, 3b... Pipe, 5... Separator, 11, 31, 31b... First end, 12, 32, 32b... Second end Parts 13, 13a... Communication hole 21, 21a... First end plate 22, 22a... Second end plate 23... Resonance chamber 33... Third end 34... Fourth end 41... First Welded part 42... Second welded part 43... Third welded part 44... Fourth welded part 45... Fifth welded part 51... Welded part 100, 100a... Muffler 311, 311b... Opening, A... central axis, R... non-welding area.

Claims (3)

a silencer,
an inner pipe through which exhaust gas passes, the inner pipe having a communication hole communicating between the inside and the outside of the inner pipe;
an outer shell member arranged to surround the outer periphery of the inner tube;
a passage forming portion disposed in a space formed between the inner tube and the outer shell member, the passage forming portion forming a passage connecting the communication hole and an opening opening to the space;
with
The passage-forming portion is fixed to the outer peripheral surface of the inner pipe by a plurality of welded portions, which are portions where the passage-forming portion and the inner pipe are welded,
A muffler, wherein a region extending in a circumferential direction of the inner pipe in a range in which the communication hole is provided with respect to a direction along the central axis of the inner pipe is a non-welded region in which the plurality of welded portions are not provided. A muffler according to claim 1,
A muffler, wherein at least one of the plurality of welded portions is arranged at a position opposite to the opening along the central axis with respect to the communicating hole. A muffler according to claim 1 or claim 2,
The passage-forming portion has a length in a direction along the central axis, and is arranged on the outer peripheral surface so as to cover a portion of the inner pipe so as to have the opening, thereby forming the passage. death,
The plurality of welded portions are spaced apart from each other along the contact end portion having a length in the direction along the central axis among the end portions contacting the outer peripheral surface of the passage forming portion. arranged side by side with space
The welding area of the first welded portion located closest to the opening among the plurality of welded portions provided at the contact end is the same as that of the welded portions other than the first welded portion among the plurality of welded portions. A silencer, larger than the respective weld area.

Images