JP7419218B2 - Method for manufacturing components of a silencer and method for manufacturing a silencer - Google Patents

Description

The present invention relates to a method for manufacturing components of a silencer, and a method for manufacturing a silencer .

2. Description of the Related Art Vehicles such as automobiles are equipped with an exhaust pipe that guides exhaust gas discharged from an internal combustion engine to the outside of the vehicle, and a muffler is installed in the exhaust pipe.

Conventionally, in order to enhance the silencing effect of this muffler, a cover pipe was provided on the outside of the pipe located inside the muffler, and a plurality of communication holes were drilled in the part of the pipe where the cover pipe was located, so that the pipe and the cover pipe could be connected. A sound absorbing material is filled in the space between the two (see Patent Documents 1 and 2).

This muffler is made by wrapping a sound-absorbing material such as glass wool around the outer circumference of the pipe so as to cover the communication hole formed in the pipe, and then reducing the diameter of both ends of the fitted cover pipe using a press die. After the cover pipe is brought into contact with the pipe, the cover pipe is fixed to the pipe using a joining means such as spot welding.

However, since the diameter of the cover pipe is reduced using a diameter-reducing type, there is a possibility that a gap may be created between the reduced-diameter cover pipe and the pipe. Condensed water stored in the silencer enters through this gap, reducing the effective volume of the space filled with the sound-absorbing material and causing the sound-absorbing material to infiltrate, resulting in a reduction in sound-dampening performance. There is a possibility.

As a countermeasure for this, the fitting end of the pipe that fits into the silencer housing is formed to have a larger diameter than the part other than the fitting end, and a communicating hole is formed in the pipe and a space is provided on the outer periphery of the pipe. It has been proposed to arrange a cover pipe with a cover pipe and fit one end of the cover pipe to a fitting end (see Patent Document 3).

Patent No. 6674673 Japanese Patent Application Publication No. 6-212969 JP2004-60523A

However, in the silencer described in Patent Document 3, the length and diameter of the entire cover pipe are large, making it difficult to adjust the resonance frequency in the silencer, and increasing restrictions when arranging the cover pipe and sound absorbing material. , there is a problem that the degree of freedom in layout is narrowed.

Therefore, the present invention provides a muffler or a component of a muffler in which another pipe is provided outside the pipe and a space is formed between both pipes, and the sound muffling performance is improved by allowing condensed water to enter the space formed between the pipes. It is an object of the present invention to provide a method for manufacturing components of a silencer and a method for manufacturing a silencer, which can prevent a decrease in noise and increase the degree of freedom in layout.

In order to solve the above problems, the present invention forms a second pipe having one or more communication holes,
A U-shaped member having at least two spaced apart diameter-reduced parts, a large-diameter part having a larger diameter than the reduced-diameter parts, and an opening into which the second pipe can be inserted. form,
The axial length of the second pipe is shorter than the axial length of the U-shaped member,
The second pipe is housed inside the U-shaped member from the opening so that the second pipe is located inside two reduced diameter parts,
Thereafter, the U-shaped member is deformed in a direction in which the opening is closed, and at least two narrow diameter portions spaced apart from each other are formed between the narrow diameter portions on the outside of the narrow diameter portion in the radial direction. forming a first pipe having a bulging portion that swells;
A structural member of a silencer, characterized in that the outer surfaces of both ends of the second pipe are fitted with the inner surface of the narrow diameter part, so that the second pipe is located inside the bulging part. This is a manufacturing method.

A sound absorbing material is wound around the outer periphery of the second pipe so as to cover the communication hole,
Thereafter, the second pipe may be placed inside the U-shaped member through the opening so that the second pipe is located inside the two reduced diameter portions .

forming a second pipe with one or more communicating holes;
A U-shaped member having at least two spaced apart diameter-reduced parts, a large-diameter part having a larger diameter than the reduced-diameter parts, and an opening into which the second pipe can be inserted. form,
The axial length of the second pipe is shorter than the axial length of the U-shaped member,
The second pipe is housed inside the U-shaped member from the opening so that the second pipe is located inside two reduced diameter parts,
Thereafter, the U-shaped member is deformed in a direction in which the opening is closed, and at least two narrow diameter portions spaced apart from each other are formed between the narrow diameter portions on the outside of the narrow diameter portion in the radial direction. forming a first pipe having a bulging portion that swells;
A method for manufacturing a silencer , characterized in that the outer surfaces of both ends of the second pipe are fitted with the inner surface of the narrow diameter part, so that the second pipe is located inside the bulging part. It is.

A sound absorbing material is wound around the outer periphery of the second pipe so as to cover the communication hole,
Thereafter, the second pipe may be placed inside the U-shaped member through the opening so that the second pipe is located inside the two reduced diameter portions.

According to the present invention, the first pipe has two or more small diameter parts and the bulging part, and the axial length of the first pipe is shorter than the axial length of the first pipe. By providing a second pipe, and fitting the outer surfaces of both ends of the second pipe with the inner surface of the narrow diameter portion, the second pipe is housed so as to be located inside the bulging portion. , it is possible to prevent water from entering between the first pipe and the second pipe, and thereby prevent a deterioration in silencing performance.

1 is a perspective view of structural members used in a muffler according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view of FIG. 1. A partially enlarged view of FIG. 2. FIG. 2 is a vertical cross-sectional view of FIG. 1. FIG. 2 is a diagram for explaining an example in which the constituent members of FIG. 1 are applied as members of a silencer. FIG. 2 is a diagram for explaining a method of manufacturing the component shown in FIG. 1; FIG. 3 is a vertical cross-sectional view of an example of a component used in a silencer according to a second embodiment of the present invention. FIG. 6 is a vertical cross-sectional view of another example of the structural member used in the silencer according to the second embodiment of the present invention. FIG. 6 is a vertical cross-sectional view of another example of the structural member used in the silencer according to the second embodiment of the present invention.

Embodiments of the present invention will be described based on examples shown in the drawings.
[Example 1]
1 is a perspective view of a component 1 (hereinafter referred to as component 1) of a silencer that constitutes a silencer according to Example 1 of the present invention, and FIG. 2 is a cross-sectional view (cross-sectional view) including the axis of FIG. ), FIG. 4 shows a cross-sectional view (longitudinal cross-sectional view) in a direction perpendicular to the axis.

As shown in FIGS. 1 to 4, the component 1 has a cylindrical first pipe 2, and the first pipe 2 has at least two narrow diameter parts 3, A bulging portion 4 that swells outward in the radial direction from the narrow diameter portion 3 is formed between the narrow diameter portions 3 and 3.

In this embodiment, two cylindrical narrow-diameter parts 3, 3, one each, are provided at both ends of the first pipe 2 in the axial direction (XX direction), respectively. Enlarged diameter parts 8, 8 are formed whose diameter gradually increases inward from the inner ends in the axial direction of the respective narrow diameter parts 3, 3, and the enlarged diameter parts 8, 8 are formed between the inner ends of the enlarged diameter parts 8, 8. A cylindrical bulging portion 4 having an inner diameter that is the same as the outermost diameter of the tube 8 and larger than the inner diameter of the narrow diameter portion 3 is provided. In other words, the bulging portion 4 is formed to swell outward in the radial direction from the narrow diameter portion. The narrow diameter portion 3, the bulging portion 4, and the enlarged diameter portion 8 are integrally formed.

As shown in FIGS. 1 to 4, a cylindrical second pipe 5 is housed inside the first pipe 2, and the outer surface of both ends of the second pipe 5 in the axial direction (XX direction) is A second pipe 5 is fitted into the inner surfaces of the narrow diameter portions 3 and 3, respectively, and is located inside the bulging portion 4. It is made up of heavy pipes. One or more communication holes 6 are bored in a portion of the second pipe 5 located inside the bulging portion 4 .

As shown in FIG. 4, the external shapes of the bulging portion 4 of the first pipe 2 and the vertical cross section of the second pipe 5 in a direction perpendicular to the axial direction (XX direction) are each formed into a circular shape. The axis of the bulging portion 4 of the first pipe 2 and the axis of the second pipe 5 are set to be substantially the same.

A space 7 is formed between the bulging portion 4 of the first pipe 2 and the second pipe 5, and the inside of the second pipe 5 and the inside of the space 7 communicate with each other through the communication hole 6 of the second pipe 5. ing.

The space 7 is filled with a sound absorbing material 10 such as glass wool. Note that the sound absorbing material 10 does not need to be provided in the space 7.

The length of the second pipe 5 in the axial direction (XX direction) is set shorter than the length of the first pipe 2 in the axial direction (XX direction), as shown in FIG. All of them are located inside the first pipe 2, and the gaps and overlapping end surfaces between the first pipe 2 and the second pipe 5 do not appear on the outer periphery of the first pipe 2, so they cannot be seen from the outside of the first pipe 2. , it is possible to prevent water from entering the space 7 and prevent deterioration of silencing performance due to water entry.

Further, by changing only the capacity of the space 7 and the amount of the sound absorbing material 10 accommodated in the space 7, it is possible to easily tune the resonance frequency and adjust the sound deadening performance of the sound absorbing material 10.

The component 1 can be applied, for example, to a pipe or a part of a pipe disposed within a casing 21 of a silencer 20 shown in FIG. It can be applied to the pipe 25.

Next, a method for manufacturing the component 1 will be explained.

As shown in FIG. 6(a), a cylindrical second pipe 5 having a communication hole 6 is formed in advance.

Further, as shown in FIG. 6(b), there are at least two diameter-reduced portions 31 having a U-shaped vertical cross-section and spaced apart from each other, and the diameter-reduced portion 31 is provided between the spaced-apart diameter reduction portions 31, 31. A U-shaped member 30 is formed which has a large diameter portion 33 that bulges further radially outward and has a U-shaped vertical cross section. An enlarged diameter portion 34 is formed between the reduced diameter portion 31 and the large diameter portion 33, and gradually expands outward in the radial direction from the reduced diameter portion 31 toward the large diameter portion 33. In this embodiment, a total of two reduced diameter portions 31 are provided at both ends of the U-shaped member 30, one reduced diameter portion 31 at each end.

Both ends of the U-shaped member 30 in the longitudinal section are spaced apart, and an opening 36 into which the second pipe 5 can be inserted is formed. The axial length of the second pipe 5 is set shorter than the axial length of the U-shaped member 30.

Next, as shown in FIG. 6(c), a predetermined amount of sound absorbing material 10 is wound around the outer periphery of the second pipe 5 so as to cover all the communication holes 6 of the second pipe 5. Note that the sound absorbing material 10 does not need to be wound around the outer periphery of the second pipe 5.

Next, as shown in FIG. 6(d), the second pipe 5 is inserted into the U-shaped member 30 through the opening 36, and then the second pipe 5 is inserted into the U-shaped member 30 as shown in FIG. 6(e). The second pipe 5 is housed inside the U-shaped member 30 so that both ends are located inside the diameter-reduced portion 31, respectively.

Next, the entire U-shaped member 30 is deformed in a direction in which the opening 36 of the U-shaped member 30 is closed, and after forming the U-shaped member 30 so that its vertical cross-sectional shape is O-shaped, the abutted ends are joined by welding. As a result, the reduced diameter portion 31 is deformed and formed into the narrow diameter portion 3, and the large diameter portion 33 is deformed and formed into the bulged portion 4, and at least two narrow diameter portions 3, 3 are formed apart from each other. , a bulging portion 4 is formed between the narrow diameter portions 3, 3 to form the first pipe 2. Furthermore, the outer surfaces of both ends of the second pipe 5 are fitted with the inner surface of the narrow diameter portion 3 so that the second pipe 5 is positioned inside the bulging portion 4 .

Next, the first pipe 2 and the second pipe 5 are joined at a plurality of locations by spot welding and fixed to each other to form the component 1 as shown in FIG. 6(f).

Note that the component 1 can be formed using any other manufacturing method in addition to the manufacturing method described above.
[Example 2]
In the above-mentioned Example 1, the external shape of the longitudinal section in the direction perpendicular to the axial direction of the bulging portion 4 of the first pipe 2 was formed into a circular shape. It can be formed into the shape of

The external shape of the vertical cross section of the bulging portion 4 may be formed into, for example, an elliptical shape as shown in FIG. 7, a polygonal shape such as a hexagonal shape as shown in FIG. 8, or an oval shape as shown in FIG. good.

The shape of the U-shaped member may be changed depending on the external shape of the vertical cross section of the bulging part 4, or the shape of the U-shaped member can be changed by using an arbitrary molding process according to the external shape of the vertical cross section of the bulging part 4. The external shape of the vertical cross section of the bulging portion 4 of the pipe 2 can be formed into any shape.

The rest of the structure is the same as that of the first embodiment, so the explanation thereof will be omitted.

The second embodiment also provides the same effects as the first embodiment.

In the second embodiment, the outer shape of the vertical cross-section of the bulging portion 4 of the first pipe 2 is further changed according to the shape of the peripheral parts in the muffler, so that the outer shape of the bulge part 4 is changed in accordance with the shape of the peripheral parts in the muffler. Interference can be avoided, and the silencing capacity in the space 7 of the bulge 4 can be easily secured.
[Example 3]
In the above embodiment, the present invention is applied to a pipe disposed within the casing 21 of the muffler 20, but the muffler may be constructed of only the component 1.

The rest of the structure is the same as that of the first and second embodiments, so the explanation thereof will be omitted.

The third embodiment also provides the same effects as the first and second embodiments.

1 Constituent members of the silencer 2 First pipe 3 Narrow diameter part 4 Swelling part 5 Second pipe 6 Communication hole 10 Sound absorbing material 20 Silencer 30 U-shaped member 31 Reduced diameter part 33 Large diameter part 36 Opening part

Claims (4)

forming a second pipe with one or more communicating holes;
A U-shaped member having at least two spaced apart diameter-reduced parts, a large-diameter part having a larger diameter than the reduced-diameter parts, and an opening into which the second pipe can be inserted. form,
The axial length of the second pipe is shorter than the axial length of the U-shaped member,
The second pipe is housed inside the U-shaped member from the opening so that the second pipe is located inside two reduced diameter parts,
Thereafter, the U-shaped member is deformed in a direction in which the opening is closed, and at least two narrow diameter portions spaced apart from each other are formed between the narrow diameter portions on the outside of the narrow diameter portion in the radial direction. forming a first pipe having a bulging portion that swells;
A structural member of a silencer, characterized in that the outer surfaces of both ends of the second pipe are fitted with the inner surface of the narrow diameter part, so that the second pipe is located inside the bulging part. manufacturing method. A sound absorbing material is wound around the outer periphery of the second pipe so as to cover the communication hole,
Thereafter, the second pipe is disposed inside the U-shaped member from the opening so that the second pipe is located inside two reduced diameter portions . A method of manufacturing the component of the silencer described above. forming a second pipe with one or more communicating holes;
A U-shaped member having at least two spaced apart diameter-reduced parts, a large-diameter part having a larger diameter than the reduced-diameter parts, and an opening into which the second pipe can be inserted. form,
The axial length of the second pipe is shorter than the axial length of the U-shaped member,
The second pipe is housed inside the U-shaped member from the opening so that the second pipe is located inside two reduced diameter parts,
Thereafter, the U-shaped member is deformed in a direction in which the opening is closed, and at least two narrow diameter portions spaced apart from each other are formed between the narrow diameter portions on the outside of the narrow diameter portion in the radial direction. forming a first pipe having a bulging portion that swells;
A method for manufacturing a silencer , characterized in that the outer surfaces of both ends of the second pipe are fitted with the inner surface of the narrow diameter part, so that the second pipe is located inside the bulging part. . A sound absorbing material is wound around the outer periphery of the second pipe so as to cover the communication hole,
3. After that, the second pipe is disposed inside the U-shaped member from the opening so that the second pipe is located inside two reduced diameter portions. Method of manufacturing the silencer described.

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