JP7116140B2 - Exhaust pipe and exhaust pipe manufacturing method - Google Patents

Description

The present disclosure relates to exhaust pipes used, for example, in internal combustion engines.

Conventionally, when joining two parts constituting an exhaust pipe, a technique of press-fitting one member into another member and then welding is used. Japanese Patent Laid-Open No. 2002-100000 discloses a vehicle muffler in which a cylindrical portion of an outer plate is press-fitted into a cylindrical outer shell and then laser-welded.

JP 2003-113714 A

The load required for press-fitting varies greatly due to a slight dimensional difference between the two parts involved in press-fitting. Even if two parts are manufactured to meet the set dimensional tolerances, if the size of the outer part is small and the size of the inner part is large, the load required for press-fitting may become large. When the load applied to the work in the press-fitting process increases, deformation and damage are more likely to occur.

An object of the present disclosure is to propose a technique for suppressing deformation and damage of an exhaust pipe while ensuring the tightness of the press-fit portion. Another object of the present disclosure is to propose a technique for facilitating the manufacture of exhaust pipes.

One aspect of the present disclosure is an exhaust pipe including a tubular main body and a blocking part that is arranged in an opening of the main body and blocks a part or all of the opening, and includes an insertion part and an inserted part. , provided. The insertion portion is provided in the first portion, which is either one of the body portion and the closing portion, and has a tubular shape. The inserted portion is provided in a second portion, which is one of the body portion and the closing portion and is different from the first portion, and has a tubular shape into which the insertion portion is inserted. The insertion portion is provided with a deformation structure that promotes radial deformation of the insertion portion.

With such a configuration, since the insertion section has a deformation structure, the insertion section is easily deformed inward when the insertion section is inserted into the inserted section. Therefore, it is possible to prevent the load required for insertion from becoming excessively large. As a result, in the insertion process, it is possible to secure the tightness of the press-fit portion and to suppress deformation and damage of the exhaust pipe caused by an increase in the load applied to the body portion and the closing portion.

In the exhaust pipe described above, the modified structure may include a slit formed in the end surface of the insertion portion in the insertion direction. With such a configuration, the deformation of the end portion of the insertion portion in the insertion direction can be promoted by the slit.

Further, in the exhaust pipe described above, the modified structure may include a protruding portion in which a portion of the tubular portion of the insertion portion protrudes toward the inside of the insertion portion. With such a configuration, the deformation of the insertion portion can be promoted by the projecting portion. This is because the formation of the projecting portion allows a portion of the cylindrical portion to enter the inner side, thereby forming a space for the cylindrical portion to deform toward the center.

Moreover, in the exhaust pipe described above, the insertion portion and the inserted portion may be welded. The deformable structure may be located on the insertion direction side of the insertion portion with respect to the welded portion. With such a configuration, the overlapped portion between the main body and the closing portion is welded without being restricted by the shape of the deformable structure, so that the joining of the main body and the closing portion by welding can be preferably performed. .

Another aspect of the present disclosure is a method of manufacturing an exhaust pipe that includes a tubular main body, and a blocking part that is arranged in an opening of the main body and blocks part or all of the opening. The exhaust pipe includes an insertion portion and an inserted portion. The insertion portion is provided in a first portion that is either one of the body portion and the closing portion, and has a tubular shape. The inserted portion is provided in a second portion different from the first portion of the body portion and the closing portion, and has a tubular shape into which the insertion portion can be inserted. The insertion portion is provided with a deformation structure that promotes radial deformation of the insertion portion. In the above manufacturing method, the inserting portion is inserted into the inserted portion, and the inserting portion and the inserted portion are welded on the side opposite to the inserting direction of the inserting portion from the position where the deformation structure is provided. and including.

With such a manufacturing method, since the insertion portion has a deformation structure, the insertion portion is easily deformed inward when the insertion portion is inserted into the insertion target portion. Therefore, the load required for insertion is prevented from becoming excessively large, and the manufacture of the exhaust pipe can be facilitated. In addition, since the main body and the closing part are welded at a position different from that of the deformable structure, the overlapping part between the main body and the closing part can be welded without being restricted by the shape of the deformable structure. can be suitably performed.

It is an exploded perspective view showing a silencer of a 1st embodiment which is an example of an exhaust pipe. It is a sectional view of the silencer of a 1st embodiment. It is an enlarged view which shows the 1st closure part of the silencer of 1st Embodiment, and the edge part of a main-body part. It is a sectional view showing the 1st closing part of the silencer of a 1st embodiment, and the end of a main part. It is a sectional view of a silencer of a modification of a 1st embodiment. It is a sectional view of a silencer of a modification of a 1st embodiment. It is an exploded perspective view of the muffler of 2nd Embodiment.

Embodiments of the present disclosure will be described below with reference to the drawings.
[1. First Embodiment]
[1-1. Configuration of silencer]
A muffler 1 shown in FIGS. 1 to 3 is a muffler used in an exhaust system forming an exhaust gas flow path of an internal combustion engine. The muffler 1 includes a body portion 11 , a first closing portion 12 and a second closing portion 13 . The muffler 1 may include an inlet pipe 14 and an outlet pipe 15 (hereinafter also simply referred to as pipes).

The body portion 11 is a so-called outer shell and has a tubular shape. A central axis A shown in FIG. In the present disclosure, the central axis is a straight line that passes through the center of gravity position in the cross section of the cylindrical portion. The cross-sectional shape of the main body 11 taken along a plane orthogonal to the central axis A is not a perfect circle but a shape close to an ellipse. Openings are formed at both ends of the main body 11 in the longitudinal direction of the central axis A. As shown in FIG. The two opening end portions 11a forming the two openings are cylindrical in shape like the body portion 11. As shown in FIG. Two partition walls 16 are provided inside the main body 11 to fix the pipe inside the main body 11 and partition the internal space of the main body 11 .

The first closing portion 12 is a so-called outer plate or end plate. A cylindrical portion 21 is provided in the first closing portion 12 . Also, the first closing portion 12 may be provided with a plate portion 22 and an insertion hole 23 .

The tubular portion 21 has a tubular shape that can be inserted into the open end portion 11 a of the main body portion 11 . The cylindrical portion 21 is press-fitted into the open end portion 11a. That is, the outer edge shape of the cylindrical portion 21 before press-fitting is substantially equal to or slightly larger than the inner peripheral shape of the main body portion 11 . A taper portion 21a is provided at the end portion of the cylindrical portion 21 in the direction of insertion into the opening end portion 11a. The tapered portion 21a has a tapered shape in which the distal end in the insertion direction is located closer to the center.

Four slits 24 are formed in the cylindrical portion 21 at intervals in the circumferential direction. The four slits 24 extend in the longitudinal direction of the central axis A from the end face of the cylindrical portion 21 in the insertion direction.
The plate portion 22 extends from the end portion of the cylindrical portion 21 in the direction opposite to the insertion direction, and covers the opening of the main body portion 11 . The above-described insertion hole 23 is formed in the plate portion 22 , and the inlet pipe 14 is arranged so as to pass through the insertion hole 23 .

The second closing portion 13 has the same features as the first closing portion 12 described above. That is, it has a cylindrical portion 31, a tapered portion 31a, a plate portion 32, an insertion hole 33, and four slits . These configurations are the same as those of the cylindrical portion 21, the tapered portion 21a, the plate portion 22, the insertion hole 23, and the slit 24.

[1-2. Manufacturing method of silencer]
A method for manufacturing the silencer 1 will be described. First, the inlet pipe 14 and the outlet pipe 15 are fixed to the two partition walls 16 . After that, the assembled pipe and partition wall 16 are inserted into the main body portion 11 .

Subsequently, the first closing portion 12 is inserted into one of the pair of open ends 11a. As described above, the first closing portion 12 is press-fitted into the open end portion 11a. This press-fitting is performed using a press-fitting device.

Subsequently, the body portion 11 and the first closing portion 12 are welded together. As shown in FIG. 4, the end surface 11b of the body portion 11 is arranged so as to overlap the cylindrical portion 21. As shown in FIG. Welding is performed near the end face 11b, preferably between the end face 11b and the slit 24, more preferably along the end face 11b, to form a weld bead. That is, a weld line is formed at a position along the end face 11b or at a position near the end face 11b. Note that the tip of the slit 24 opposite to the insertion direction is located on the insertion direction side of the end surface 11b. That is, the welding between the main body portion 11 and the first closing portion 12 is performed at a position on the side opposite to the insertion direction with respect to the slit 24 .

Like the first closing portion 12, the second closing portion 13 is press-fitted into the open end portion 11a and then welded. The second closing portion 13 may be press-fitted after the welding of the first closing portion 12 is completed, or the first closing portion 12 and the second closing portion 13 may be press-fitted after the first closing portion 12 and the second closing portion 13 are press-fitted. Welding of the closing portion 13 may be performed. The inserting direction of the second closing part 13 is opposite to the inserting direction of the first closing part 12 .

[1-3. effect]
According to the first embodiment detailed above, the following effects are obtained.
(1a) In the muffler 1 of the present embodiment, the tubular portion 21 of the first closing portion 12 has four slits 24, so that when the tubular portion 21 is inserted into the open end portion 11a, the tubular portion 21 is pushed inward. Easy to deform. Therefore, it is possible to prevent the load necessary for inserting the tubular portion 21 from becoming excessively large while ensuring the tight contact between the tubular portion 21 and the open end portion 11a. As a result, the insertion process can be easily performed. Moreover, deformation and damage of the muffler 1 caused by an increase in the load applied to the main body portion 11 and the first closing portion 12 during the insertion process can be suppressed. Since the second closing portion 13 has the same shape as the first closing portion 12, the same effect can be obtained.

(1b) The four slits 24 extend in the longitudinal direction of the central axis A of the insertion portion from the end surface 11b of the cylindrical portion 21 in the insertion direction. With such a configuration, the deformation of the end of the first closing portion 12 in the insertion direction can be promoted by the slit 24 . This is because the presence of the slits 24 lowers the strength around the tubular portion 21 and forms a circumferential gap for the tubular portion 21 to deform toward the center. If there is no gap in the circumferential direction, even if a force directed toward the central axis A is applied to the entire circumference of the cylindrical portion 21, in order for the cylindrical portion 21 to deform evenly, it is necessary to reduce the diameter of the cylindrical portion 21. do not have. However, such deformation is difficult with metallic materials. As a result, the applied force is canceled by the stress in the circumferential direction of the cylindrical portion 21, and the cylindrical portion 21 is less likely to deform in the central axis A direction even if a load is applied. However, the slits 24 make the above-mentioned problem less likely to occur and make deformation easier.

(1c) In the silencer 1 described above, the body portion 11 and the first closing portion 12 are joined by welding the opening end portion 11a and the first closing portion 12 together. Welding between the body portion 11 and the first closing portion 12 is performed at a position opposite to the insertion direction from the slit 24 . That is, the slit 24 is located on the inserting direction side of the tubular portion 21 with respect to the welded portion. Therefore, the danger that welding cannot be properly performed due to the slit 24 is suppressed, so that the joining of the main body portion 11 and the first closing portion 12 by welding can be preferably performed.

[1-4. Correspondence]
In the first embodiment, the muffler 1 is an example of an exhaust pipe. Also, the first closing portion 12 and the second closing portion 13 are examples of the closing portion. Further, the tubular portion 21 is an example of the insertion portion, and the open end portion 11a is an example of the inserted portion. Also, the plurality of slits 24 and 34 is an example of a modified structure. In the first embodiment, the first closing portion 12 and the second closing portion 13 correspond to the first portion including the insertion portion, and the body portion 11 corresponds to the second portion including the inserted portion.

The deformable structure that promotes radial deformation of the insertion portion is the following structure. When a load directed toward the center axis is applied to the insertion portion when comparing the case where the insertion portion is provided with the deformation structure and the case where the deformation structure is not provided, The insertion portion deforms radially inward. That is, when the insertion portion is to be deformed to the same radially inner position, the deformation can be achieved with a smaller force when the deformation structure is provided.

[1-5. Modification of First Embodiment]
In 1st Embodiment, the muffler provided with a slit was illustrated as a modified structure. However, the deformation structure need not be a slit.

A muffler 101 shown in FIGS. 5 and 6 is an example of a muffler having a modified structure having a function similar to that of a slit. Compared to the silencer 1, the silencer 101 does not have the slits 24, but has four protrusions 103 instead of the slits 24. As shown in FIG. The projecting portion 103 has a shape in which a part of the cylindrical portion of the inserting portion is extruded so as to protrude toward the central axis of the inserting portion. The projecting portion 103 has a length extending from the insertion direction end of the cylindrical portion 21 toward the side opposite to the insertion direction.

With such a configuration, the projecting portion 103 can promote elastic deformation of the cylindrical portion 21 . This is because the formation of the projecting portion 103 causes the internal space to become the “circumferential gap for the cylindrical portion 21 to deform toward the center” described in (1b) above. Moreover, since the projecting portion 103 bends more easily than the portion around the projecting portion 103 in the tubular portion 21, this also promotes deformation.

The shape of the protruding portion 103 may not be semicircular as shown in FIG. For example, it may have a shape in which the tip on the protruding center side is pointed. Moreover, it may have a length in the circumferential direction of the cylindrical portion 21 .

[2. Second Embodiment]
[2-1. Configuration of silencer]
The second embodiment exemplifies an exhaust pipe having a shape different from that of the first embodiment as an example of the exhaust pipe.

A catalyst case 201 shown in FIG. 7 is used in an exhaust system forming an exhaust gas flow path of an internal combustion engine. The catalyst case 201 includes a main body portion 211 , a first closing portion 212 and a second closing portion 213 .

The body portion 211 is a so-called outer shell and has a tubular shape. Openings are formed at both ends of the body portion 211 . The two opening end portions 211a that form the two openings have the same cylindrical shape as the main body portion 211 as a whole.

The first closing part 212 is a so-called outer plate or end plate. A tubular portion 221 is provided in the first closing portion 212 . Also, the first closing portion 212 may be provided with a tapered wall portion 222 and an insertion opening 223 .

The cylindrical portion 221 has a cylindrical shape that can be press-fitted into the open end portion 211a. Four slits 224 extending in the longitudinal direction of the central axis from the end face of the tubular portion 221 in the insertion direction are formed in the tubular portion 221 at intervals in the circumferential direction.

The second closure 213 has the same features as the first closure 212 described above. That is, it has a cylindrical portion 231 , a tapered wall portion 232 , an insertion opening 233 and four slits 234 . These configurations are the same as those of the tubular portion 221 , the tapered wall portion 222 , the insertion opening 223 and the slit 224 .

A method for manufacturing the catalyst case 201 will be described. The first closing portion 212 is press-fitted into one of the pair of open end portions 211a. Then, the first closing portion 212 and the body portion 211 are welded. Welding between the body portion 211 and the first closing portion 212 is performed at a position on the opposite side of the insertion direction from the slit 224 . Similarly to the first closing portion 212, the second closing portion 213 is press-fitted into the open end portion 211a and then welded.

According to the second embodiment described in detail above, the same effects as the effects (1a) to (1c) of the first embodiment described above are obtained.
[2-2. Correspondence]
In the second embodiment, catalyst case 201 is an example of an exhaust pipe. Also, the first closing portion 212 and the second closing portion 213 are examples of the closing portion. Further, the tubular portion 221 is an example of an insertion portion, and the open end portion 211a is an example of an inserted portion. Also, the plurality of slits 224 and 234 are an example of a modified structure. In the second embodiment, the first closing portion 212 and the second closing portion 213 correspond to the first portion including the insertion portion, and the body portion 211 corresponds to the second portion including the inserted portion.

[3. Other embodiments]
Although the embodiments of the present disclosure have been described above, the present disclosure is by no means limited to the above-described embodiments, and needless to say, can take various forms as long as they fall within the technical scope of the present disclosure.

(3a) In each of the embodiments described above, the silencer and the catalyst case were exemplified as examples of the exhaust pipe. However, the exhaust pipe of the present disclosure is not limited to the muffler and catalyst case, and can be employed in various parts that make up the exhaust pipe. The term "exhaust pipe" as used herein broadly means, for example, a pipe used for exhaust gas from an internal combustion engine.

(3b) In each of the above-described embodiments, the first closing portion and the second closing portion correspond to the first portion including the insertion portion, and the main body portion corresponds to the second portion including the inserted portion. However, the first closing portion and the second closing portion may be the inserted portions, and the body portion may be the insertion portion. That is, the outer edge shape of the end portion of the body portion may be configured to be smaller than the first closing portion and the second closing portion.

(3c) In each of the above embodiments, slits or protrusions are shown as examples of modified structures. However, as long as it is a configuration that promotes deformation, the deformation structure may be other than the above-described configuration. For example, the deformable structure may be a portion that is thinner than its surroundings, or a portion that is made of a material that is more flexible than its surroundings. Alternatively, the modified structure may have both slits and protrusions. The number of deformation structures provided in the insertion portion is not particularly limited, and may be one to three, or may be five or more. In each of the above-described embodiments, the slits are so-called cutouts formed in the end faces. However, the slit may also be a gap with a closed circumference. Also, the slit and the protruding portion may have a length in the circumferential direction of the insertion portion.

(3d) In each of the above-described embodiments, the configuration in which welding is performed at a position in the direction opposite to the insertion direction with respect to the slit and the projection is exemplified. However, the weld may also be made at the location where the deformation structure is provided. Moreover, the structure which does not weld an insertion part and a to-be-inserted part may be sufficient.

(3e) The specific shapes of the body portion, the closing portion, the insertion portion, and the inserted portion are not limited to the configurations disclosed in the above embodiments. For example, the cross-sectional shapes of the insertion portion and the inserted portion may be circular, elliptical, circular, or polygonal. The insertion section may be inserted into the insertion section in a manner that does not apply a large amount of pressure. The body portion may vary in cross-sectional shape in the length direction. Only one closure may be used.

Note that the closing part in the present disclosure may be configured to block part or all of the opening of the main body. Here, "partially blocking the opening" means that, as in each of the above-described embodiments, when the cross-sectional area of the opening of the main body and the cross-sectional area of the opening of the blocking part are compared, It means that the cross-sectional area of the opening of the part is small. The opening portion of the blocking portion includes the insertion hole 23 of the first blocking portion 12 and the insertion hole 33 of the second blocking portion 13 in the muffler 1 of the first embodiment, and the first opening of the catalyst case 201 of the second embodiment. The insertion opening 223 of the closing part 212 and the insertion opening 233 of the second closing part 213 correspond. Moreover, when the closing portion closes the entire opening, for example, a through hole may be formed in the cylindrical wall surface of the body portion, and the fluid may flow through the hole.

(3f) A plurality of functions possessed by one component in the above embodiment may be realized by a plurality of components, or a function possessed by one component may be realized by a plurality of components. . Moreover, a plurality of functions possessed by a plurality of components may be realized by a single component, or a function realized by a plurality of components may be realized by a single component. Also, part of the configuration of the above embodiment may be omitted. Moreover, at least part of the configuration of the above embodiment may be added or replaced with respect to the configuration of the other above embodiment.

DESCRIPTION OF SYMBOLS 1, 101, 201... Muffler 11, 211... Main-body part 11a... End part 11a, 211a... Open end part 11b... End surface 12, 212... First closing part 13, 213... Second closing part , 14... inlet pipe, 15... outlet pipe, 16... partition wall, 21, 31, 221, 231... cylindrical portion, 21a, 31a... tapered portion, 22, 32... plate portion, 23, 33... insertion hole, 24, 34, 224, 234... slit, 103... projecting portion, 222, 232... tapered wall portion, 223, 233... insertion port

Claims (4)

An exhaust pipe comprising a cylindrical main body and a blocking part disposed in an opening of the main body and blocking part or all of the opening,
a cylindrical insertion portion provided in a first portion that is one of the body portion and the closing portion;
A second part, which is different from the first part of the main body part and the closing part, is inseparably provided to a second part, and has a tubular shape, into which the insertion part is inserted by press fitting . , and
The insertion portion is provided with a deformation structure that promotes radial deformation of the insertion portion,
The insertion portion and the inserted portion are fixed by welding at the press-fitted and closely attached portions ,
The deformable structure is an exhaust pipe positioned closer to the insertion direction of the insertion portion than the welded portion. An exhaust pipe according to claim 1,
The exhaust pipe, wherein the modified structure includes a slit formed in an end surface of the insertion portion in the insertion direction. An exhaust pipe according to claim 1,
The modified structure is an exhaust pipe, wherein a portion of the tubular portion of the insertion portion includes a protruding portion that protrudes toward the inside of the insertion portion. A method for manufacturing an exhaust pipe comprising a cylindrical main body and a closing part arranged in an opening of the main body and blocking a part or all of the opening,
The exhaust pipe has a cylindrical insertion portion provided in a first portion that is one of the main body portion and the closing portion, and the first portion of the main body portion and the closing portion. an inserted portion which is inseparably provided in a second portion, which is a different one, and which has a tubular shape and into which the insertion portion is inserted; and the insertion portion is deformed in the radial direction of the insertion portion Further, the insertion portion and the inserted portion are welded together, and the deformation structure is located on the insertion direction side of the insertion portion relative to the welded portion. cage,
inserting the insertion portion into the inserted portion by press- fitting ;
Welding the press-fitted and closely attached portions of the insertion portion and the inserted portion on the side opposite to the insertion direction of the insertion portion from the position where the deformation structure is provided. manufacturing method.

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