Silencer manufacturing method

Abstract

To improve the assemblability of a pipe.SOLUTION: A first end of a first pipe is arranged in a housing so as to manufacture a noise eliminator. A second pipe is inserted into the first pipe from outside the housing, and the second pipe is therefore arranged in the housing. The second pipe is inserted from a second end of the first pipe located on the opposite side from the first end of the first pipe. The noise eliminator is thus manufactured which retains the first pipe connected to the second pipe inside an end of the housing. A first end of the second pipe is moved by the insertion to a position beyond at least the first end of the first pipe. A second end of the second pipe located on the opposite side from the first end of the second pipe is arranged inside the first pipe.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a method for manufacturing a silencer. [Background technology]

[0002] 2. Description of the Related Art In the exhaust system of an internal combustion engine, a silencer is used which has two pipes: an inlet pipe for introducing exhaust gas into a housing, and an outlet pipe for discharging exhaust gas from the housing.

[0003] For example, Patent Document 1 discloses a technology for preventing the pipes of a silencer from shifting out of alignment by inserting a first pipe into a first end of a housing, reducing the diameter of a second end of the housing opposite the first end by spinning, and then inserting a second pipe into the housing from the reduced-diameter second end. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2021-105377 Summary of the Invention [Problem to be solved by the invention]

[0005] In the prior art disclosed in Patent Document 1, the tip of the first pipe is flared to ensure ease of insertion when the second pipe is inserted into the first pipe through the reduced diameter portion of the housing. If this flaring is not performed, the ease of assembling the two pipes may be reduced.

[0006] One aspect of the present disclosure is to improve pipe assembly. [Means for solving the problem]

[0007] One aspect of the present disclosure is a method for manufacturing a silencer, comprising: preparing a housing; and arranging a second pipe. Preparing the housing includes preparing a housing having a central portion and a first cylindrical end portion and a second cylindrical end portion located on either side of the central portion and having a smaller diameter than the central portion, and includes preparing a housing in which a first pipe is inserted into the first cylindrical end portion and a first end of the first pipe is disposed inside the housing.

[0008] Arranging the second pipe includes arranging the second pipe inside the housing by inserting the second pipe from outside the housing into the first pipe arranged in the housing. Positioning the second pipe includes inserting the second pipe from a second end of the first pipe located opposite the first end of the first pipe, and moving the first end of the second pipe to a position where it passes through at least the first end of the first pipe and where the second end of the second pipe located opposite the first end of the second pipe is positioned inside the first pipe.

[0009] The silencer is configured to hold the first pipe, to which the second pipe is connected, inside the first cylindrical end. According to this manufacturing method, the second pipe can be easily inserted into the first pipe even if the first end of the first pipe is not flared, improving the ease of assembly of the first pipe and the second pipe.

[0010] In one aspect of the present disclosure, positioning the second pipe may include moving a first end of the second pipe inserted from the second end of the first pipe at least to the inside of the second cylindrical end so that the second pipe is held inside the second cylindrical end while the second pipe is connected to the first pipe.

[0011] According to this manufacturing method, the assembly of the housing and the second pipe is improved. In one aspect of the present disclosure, the housing may be formed by a first end of the cylindrical body and a reduced diameter at a second end of the cylindrical body located opposite the first end of the cylindrical body.

[0012] Providing the housing may include providing a first cylindrical end, positioning a first end of a first pipe within the housing, and providing a second cylindrical end. Providing the first cylindrical end portion may include reducing a diameter of a first end of the cylindrical body. Arranging the first end of the first pipe inside the housing may include inserting the first pipe into the first cylindrical end portion. Providing the second cylindrical end portion may include reducing a diameter of a second end of the cylindrical body with the first pipe inserted into the first cylindrical end portion.

[0013] Positioning the second pipe may include moving a first end of the second pipe inserted from the second end of the first pipe at least to the inside of the second cylindrical end so that the second pipe is held inside the second cylindrical end while the second pipe is connected to the first pipe.

[0014] According to this manufacturing method, the second pipe can be easily inserted into the first pipe even if the first end of the first pipe is not flared, improving the ease of assembly of the first pipe, the second pipe, and the housing.

[0015] One aspect of the present disclosure is a method for manufacturing a silencer, comprising connecting, providing a first cylindrical end, providing a second cylindrical end, and positioning. The connecting includes connecting the first pipe and the second pipe by inserting the second pipe inside the first pipe so that a first end of the second pipe is positioned outside the first pipe and a second end of the second pipe, which is located opposite the first end of the second pipe, is positioned inside the first pipe.

[0016] Providing the first cylindrical end portion includes providing a first cylindrical end portion at a first end of the cylindrical body, the first cylindrical end portion having a smaller diameter than the cylindrical body. Providing the second cylindrical end portion includes providing a second cylindrical end portion having a smaller diameter than the cylindrical body at a second end of the cylindrical body located opposite the first end of the cylindrical body.

[0017] The placing includes placing the coupled first and second pipes at least partially within the tubular body. The placing includes inserting a second pipe connected to the first pipe into the first cylindrical end from a first end of the second pipe, thereby placing at least a portion of the first pipe inside the first cylindrical end, placing at least a portion of the second pipe inside the second cylindrical end, and placing the first end of the first pipe inside the cylindrical body.

[0018] The silencer is configured to hold a first pipe inside the first cylindrical end and a second pipe connected to the first pipe inside the second cylindrical end. According to this manufacturing method, the second pipe can be easily inserted into the first pipe even if the first end of the first pipe is not flared, improving the ease of assembly of the first pipe and the second pipe.

[0019] In one embodiment of the present disclosure, providing the second cylindrical end portion includes providing the second cylindrical end portion substantially coaxially with the first cylindrical end portion. The method may include providing a curved end. According to this manufacturing method, when inserting the second pipe into the second cylindrical end, the position at which the second pipe is inserted into the second cylindrical end is less likely to shift, thereby improving the ease of assembling the second pipe to the housing.

[0020] In one aspect of the present disclosure, providing the second cylindrical end may include providing the second cylindrical end such that the inner diameter of the portion of the cylindrical body adjacent to the second cylindrical end becomes smaller as it approaches the second cylindrical end.

[0021] According to this manufacturing method, when the second pipe is inserted into the second cylindrical end, the second pipe is easily guided into the second cylindrical end, improving the ease of assembly of the housing and the second pipe.

[0022] In one embodiment of the present disclosure, the second pipe may include a retaining member on an outer peripheral surface of the second end, and the outer diameter of the second pipe including the retaining member at the second end may be equal to or greater than the inner diameter of the first pipe before the second pipe is inserted into the first pipe.

[0023] According to this configuration, the second pipe can be held by the first pipe while preventing the second pipe from damaging the inner surface of the first pipe when the second pipe is inserted into the first pipe.

[0024] In one embodiment of the present disclosure, the first pipe may have a main body portion and a reduced diameter portion. The main body portion is located between the first end of the first pipe and a second end of the first pipe located opposite the first end of the first pipe. The reduced diameter portion is located between the main body portion and the second end of the first pipe. The inner diameter of the second end of the first pipe may be larger than the inner diameter of the main body portion. The inner diameter of the reduced diameter portion may be formed to decrease toward the main body portion.

[0025] With this configuration, the second pipe can be easily inserted into the first pipe, improving the ease of assembly of the first pipe and the second pipe. [Brief explanation of the drawings]

[0026] [Figure 1] FIG. 2 is a front view of the silencer, showing the housing in cross section. [Figure 2] 3 is a flowchart showing a method for manufacturing the silencer according to the first embodiment. [Figure 3] Fig. 3A is a diagram illustrating a first cylindrical end forming step of the first embodiment, Fig. 3B is a diagram illustrating a first pipe arranging step of the first embodiment, and Fig. 3C is a diagram illustrating a second cylindrical end forming step of the first embodiment. [Figure 4] 4A and 4B are diagrams illustrating the second pipe arrangement step of the first embodiment. [Figure 5] 10 is a flowchart showing a method for manufacturing a silencer according to a second embodiment. [Figure 6]10A to 10C are diagrams illustrating a pipe connecting step according to the second embodiment. [Figure 7] Fig. 7A is a diagram illustrating a first cylindrical end forming step of the second embodiment, Fig. 7B is a diagram illustrating a second cylindrical end forming step of the second embodiment, and Figs. 7C and 7D are diagrams illustrating a connecting pipe arranging step of the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the drawings. [1. First embodiment] [1-1. Silencer configuration] A silencer 1 shown in FIG. 1 is mounted on a vehicle such as an automobile, and is a component that constitutes at least a part of the flow path of exhaust gas generated by the internal combustion engine of the vehicle.

[0028] The silencer 1 includes a housing 10, a first pipe 20, and a second pipe 30. The housing 10 is a cylindrical metal member that functions as an outer pipe that covers the first pipe 20 and the second pipe 30.

[0029] Housing 10 has a first cylindrical end portion 11, a second cylindrical end portion 12, a central portion 13, a first sloped portion 14, and a second sloped portion 15. The interior surface of housing 10 defines an interior space 16 of housing 10.

[0030] The first cylindrical end 11 and the second cylindrical end 12 are cylindrical portions of the casing 10 located on either side of a central portion 13 located in the center of the casing 10, and have a smaller diameter than the central portion 13. Exhaust gas flows into the interior of the casing 10 through the second cylindrical end 12 and flows out of the casing 10 through the first cylindrical end 11. Hereinafter, the flow path of the exhaust gas flowing inside the casing 10 will be referred to as flow path A. The "inside of the casing 10" includes the space between the first pipe 20 and the casing 10, the space between the second pipe 30 and the casing 10, the interior of the first pipe 20, and the interior of the second pipe 30. The "upstream side" means the upstream side of flow path A. The "downstream side" means the downstream side of flow path A. The first cylindrical end 11 is located downstream of the central portion 13. The second cylindrical end 12 is located upstream of the central portion 13.

[0031] The first inclined portion 14 is adjacent to the first cylindrical end portion 11 of the housing 10, and is located between the first cylindrical end portion 11 and the central portion 13. The inner diameter of the first inclined portion 14 decreases from the central portion 13 toward the first cylindrical end portion 11.

[0032] The second inclined portion 15 is adjacent to the second cylindrical end portion 12 of the housing 10, and is located between the second cylindrical end portion 12 and the central portion 13. The inner diameter of the second inclined portion 15 decreases from the central portion 13 toward the second cylindrical end portion 12.

[0033] In this embodiment, both the first inclined portion 14 and the second inclined portion 15 have a tapered shape. The first inclined portion 14 and the second inclined portion 15 are not limited to a tapered shape, and may be curved, for example.

[0034] The first pipe 20 is a metal pipe that extends in a substantially straight line. The first pipe 20 is arranged on the downstream side inside the housing 10. The first pipe 20 functions as an outlet pipe that discharges exhaust gas from the housing 10. The first pipe 20 is held inside the first cylindrical end portion 11. A portion of the first pipe 20 may be arranged outside the first cylindrical end portion 11.

[0035] The first pipe 20 includes a first main body portion 21, a first large diameter portion 22, a first through hole 23, and a first reduced diameter portion 24. The first main body portion 21 has a first connecting portion 21a. The first large diameter portion 22 has a first abutting portion 22a.

[0036] The first main body portion 21 is a portion of the first pipe 20 located between the upstream end and the downstream end. The first connecting portion 21a is a portion at the upstream end of the first main body portion 21 that is connected to the second pipe 30. The first connecting portion 21a is located inside the housing 10.

[0037] The first large diameter portion 22 is located at the downstream end of the first pipe 20. The inner diameter of the first large diameter portion 22 is larger than the inner diameter of the first main body portion . The first contact portion 22a is a portion located on the outer circumferential surface of the first large diameter portion 22, and is fixed by contacting the first cylindrical end portion 11. In this embodiment, the first contact portion 22a is fixed to the first cylindrical end portion 11. In another example, the first main body portion 21 of the first pipe 20 may be arranged so that a part of it passes through the first cylindrical end portion 11 and is positioned outside the housing 10. In this case, the first abutting portion 22a of the first pipe 20 that abuts against the first cylindrical end portion 11 may be positioned upstream of the first large diameter portion 22.

[0038] The first through hole 23 is a hole that penetrates from the inside to the outside of the first pipe 20. The first through hole 23 is provided on the side surface of the first pipe 20. In particular, the first through hole 23 is provided on the side surface of the first main body portion 21 in an area that is located inside the housing 10. One or more first through holes 23 may be provided.

[0039] The first reduced diameter section 24 is located between the first main body section 21 and the first large diameter section 22, and connects the first main body section 21 and the first large diameter section 22. The inner diameter of the first reduced diameter section 24 is formed to become smaller as it approaches the first main body section 21. The first reduced diameter section 24 may be formed in a tapered shape or in a stepped shape.

[0040] The second pipe 30 is a metal pipe that extends in a substantially straight line. The second pipe 30 is arranged on the upstream side inside the housing 10. The second pipe 30 functions as an inlet pipe that introduces exhaust gas into the housing 10. The second pipe 30 is held inside the second cylindrical end portion 12. A portion of the second pipe 30 may be arranged outside the second cylindrical end portion 12.

[0041] The second pipe 30 has a second connecting portion 31 , a second abutting portion 32 , and a second through hole 33 . The second connecting portion 31 is a portion at the downstream end of the second pipe 30 that connects to the first pipe 20. The second connecting portion 31 is located inside the housing 10. The second connecting portion 31 has a holding member 4 on its outer peripheral surface. In FIG. 1, the members located inside the first pipe 20 are shown transparently by dashed lines. Specifically, the second connecting portion 31 and the holding member 4 are shown transparently. The same applies to the other FIGS. 4B, 7C, and 7D.

[0042] The holding member 4 is a belt-like member having a thickness and is elastically deformable. In this embodiment, as an example, the holding member 4 is a wire mesh. The wire mesh is formed by intertwining metal threads, either woven or unwoven. The holding member 4 is configured to apply a radial force to the first pipe 20 and the second pipe 30 by elastic deformation between the first pipe 20 and the second pipe 30, thereby holding the first pipe 20 and the second pipe 30.

[0043] The outer diameter of the second pipe 30 is smaller than both the inner diameter of the second cylindrical end 12 and the inner diameter of the first pipe 20. The outer diameter of the second connecting part 31 including the retaining member 4 is approximately the same as or slightly larger than the inner diameter of the first pipe 20 before the second connecting part 31 is inserted into the first pipe 20.

[0044] The second connecting portion 31 of the second pipe 30 is held inside the first connecting portion 21a of the first pipe 20. The holding member 4 is compressed between the outer peripheral surface of the second connecting portion 31 and the inner peripheral surface of the first connecting portion 21a. That is, the second pipe 30 is press-fitted into the first connecting portion 21a by the holding member 4 at the second connecting portion 31. This connects the first pipe 20 and the second pipe 30. The second connecting portion 31 is not fixed to the first connecting portion 21a, and the second pipe 30 can slide together with the holding member 4 inside the first pipe 20.

[0045] The first connecting portion 21a of the first pipe 20 and the second connecting portion 31 of the second pipe 30, which are portions where the first pipe 20 and the second pipe 30 are connected, are both located inside the housing 10. . The second abutment portion 32 is a portion located on the upstream side of the second pipe 30, and is fixed in abutment against the second cylindrical end portion 12. The second abutment portion 32 shown in FIG. 1 is located at the upstream end portion of the second pipe 30. However, the second abutment portion 32 may be located downstream of the upstream end portion of the second pipe 30. In other words, the upstream end portion of the second pipe 30 may be located upstream of the second cylindrical end portion 12.

[0046] The second through hole 33 is a hole that penetrates from the inside to the outside of the second pipe 30. The second through hole 33 is provided in the side surface of the second pipe 30. In particular, the second through hole 33 is provided in the region between the second connecting portion 31 and the second abutting portion 32 on the side surface of the second pipe 30. One or more second through holes 33 may be provided.

[0047] The exhaust gas flows into the silencer 1 from the upstream opening of the second pipe 30. That is, the exhaust gas passes through the inside of the second abutment portion 32 and flows through the portion of the second pipe 30 located inside the housing 10. The exhaust gas flows from the second pipe 30 into the first pipe 20 via the second connecting portion 31 and the first connecting portion 21a, passes through the inside of the first abutment portion 22a, and is discharged to the outside of the silencer 1 from the downstream opening of the first pipe 20.

[0048] At this time, the exhaust gas passes through the first through-hole 23 and the second through-hole 33 and flows out from the inside of the first pipe 20 and the second pipe 30 into the internal space 16 of the housing 10. The internal space 16 causes the exhaust gas to expand, interfere, and the like, and thus the silencer 1 exhibits a noise absorbing effect. The internal space 16 may be filled with a sound-absorbing material to improve the noise absorbing effect. A sound-absorbing material, a pipe covering the external periphery of the first pipe 20 or the second pipe 30, or the like may be provided on the outer periphery of at least one of the first pipe 20 and the second pipe 30.

[0049] [1-2. Manufacturing method of silencer] As shown in Fig. 2, the manufacturing method of the silencer 1 includes a first cylindrical end forming step S110, a first pipe arranging step S120, a second cylindrical end forming step S130, and a second pipe arranging step S140. The manufacturing method of the silencer 1 is performed in the order of the first cylindrical end forming step S110, the first pipe arranging step S120, the second cylindrical end forming step S130, and the second pipe arranging step S140. The second cylindrical end forming step S130 may be performed before the first pipe arranging step S120. Each step will be described using Figs. 3 and 4.

[0050] [1-2-1. First cylindrical end forming process] The housing 10 is formed by reducing the diameter of a first end and a second end opposite to the first end of a cylindrical body 10a, which is a cylindrical member.

[0051] As shown in FIG. 3A, the first cylindrical end forming step S110 is a step of forming a first cylindrical end 11 on the cylindrical body 10a. The first cylindrical end 11 is formed by reducing the diameter of the downstream end of the cylindrical body 10a. The diameter reduction process refers to reducing the diameter of a cylindrical member in the radial direction and processing it into a cylindrical shape with a diameter smaller than its surroundings. Hereinafter, the diameter reduction process will also be simply referred to as diameter reduction. The diameter reduction can be achieved by, for example, spinning, but may also be achieved by other processing techniques such as pressing.

[0052] Due to the diameter reduction for forming the first cylindrical end portion 11, a first inclined portion 14 is formed in the portion of the cylindrical body 10a adjacent to the first cylindrical end portion 11 on the upstream side. [1-2-2. First pipe placement process] As shown in Figures 3B and 3C, the first pipe placement process S120 is a process of placing the first connecting portion 21a of the first pipe 20 inside the cylindrical body 10a by inserting the first pipe 20 into the first cylindrical end portion 11 of the cylindrical body 10a.

[0053] The first pipe 20 enters the cylindrical body 10a from the upstream opening of the cylindrical body 10a and is inserted into the first cylindrical end portion 11. The first abutting portion 22a of the first pipe 20 abuts against the first cylindrical end portion 11. The first connecting portion 21a is disposed inside the cylindrical body 10a.

[0054] At this time, the first contact portion 22a may be fixed to the first cylindrical end portion 11. Fixation may be achieved by, for example, at least one of press-fitting, welding, and diameter expansion. In the present embodiment, in this step, the first contact portion 22a is press-fitted into the first cylindrical end portion 11. Furthermore, the periphery of the first cylindrical end portion 11 is spot-welded, thereby temporarily fixing the first contact portion 22a to the first cylindrical end portion 11. The first contact portion 22a may be fixed to the first cylindrical end portion 11 in a step subsequent to this step.

[0055] [1-2-3. Second cylindrical end forming process] 3C, the second cylindrical end portion forming step S130 is a step of forming the second cylindrical end portion 12 on the cylindrical body 10a with the first pipe 20 inserted into the first cylindrical end portion 11. The second cylindrical end portion 12 is formed by reducing the diameter of the upstream end portion of the cylindrical body 10a. The second cylindrical end portion 12 is formed approximately coaxially with the first cylindrical end portion 11.

[0056] Due to the diameter reduction for forming the second cylindrical end portion 12, a second inclined portion 15 is formed in the portion of the cylindrical body 10a adjacent to the second cylindrical end portion 12 on the downstream side. The housing 10 is obtained by forming the first cylindrical end portion 11 and the second cylindrical end portion 12 on the cylindrical body 10a in this manner.

[0057] [1-2-4. Second pipe placement process] As shown in FIG. 4A, the second pipe placement process S140 is a process of placing the second pipe 30 inside the housing 10 by inserting the second pipe 30 from the outside of the housing 10 into the first pipe 20 whose first connecting portion 21a is placed inside the housing 10.

[0058] The second pipe 30 is inserted into the first pipe 20 from the downstream end (i.e., the first large diameter portion 22) of the first pipe 20, with its upstream end (i.e., the end not provided with the holding member 4) as the head. After the head of the second pipe 30 is inserted into the first large diameter portion 22 of the first pipe 20, it is guided to the first main body portion 21 by the first reduced diameter portion 24. In this embodiment, the head of the second pipe 30 corresponds to the second abutment portion 32.

[0059] As the insertion of the second pipe 30 into the first pipe 20 progresses, the second connecting portion 31 and the holding member 4 at the downstream end of the second pipe 30 are inserted into the first pipe 20. The outer diameter of the second connecting portion 31 including the holding member 4 is approximately the same as or slightly larger than the inner diameter of the first pipe 20, so the second pipe 30 and the holding member 4 are press-fitted into the first pipe 20. In this embodiment, the press-fitting of the second pipe 30 and the holding member 4 into the first pipe 20 is progressed using a rod-shaped press-fitting jig 5 whose diameter is smaller than the inner diameter of the first pipe 20. The press-fitting jig 5 may be solid or hollow. At least a portion of the portion of the press-fitting jig 5 that abuts against the second pipe 30 when the second pipe 30 is press-fitted presses at least a portion of the thick portion of the second pipe 30.

[0060] As shown in Figure 4B, when the second pipe 30 is further inserted into the first pipe 20, the front end of the second pipe 30 passes outside the first pipe 20, advances upstream through the internal space 16 of the housing 10, and is inserted into the second cylindrical end 12.

[0061] The second pipe 30 passes through the second cylindrical end 12 and advances upstream until it abuts against the receiving jig 6 located outside the housing 10 and upstream of the second cylindrical end 12. The receiving jig 6 is The second pipe 30 may be in contact with the second cylindrical end portion 12 or may be spaced apart from the second cylindrical end portion 12. When the leading end of the second pipe 30 is in contact with the receiving jig 6, the second pipe arrangement step S140 is completed.

[0062] When the second pipe arrangement step S140 is completed, the second connecting portion 31 and the holding member 4 are both press-fitted into the inside of the first pipe 20. The second pipe 30 is connected to the first pipe 20 at the second connecting portion 31 via the holding member 4. In this embodiment, the holding member 4 is press-fitted into the first connecting portion 21a. Therefore, the second pipe 30 is connected to the first pipe 20 at the first connecting portion 21a. The first connecting portion 21a and the second connecting portion 31 are not fixed, and the second pipe 30 is slidable relative to the first pipe 20 via the holding member 4.

[0063] The second contact portion 32 contacts the second cylindrical end portion 12. The second contact portion 32 may be fixed to the second cylindrical end portion 12. The fixing may be achieved by, for example, at least one of press-fitting, welding, and diameter expansion. The second contact portion 32 may be fixed to the second cylindrical end portion 12 in a step subsequent to this step.

[0064] In the manner described above, the housing 10 is formed from the cylindrical body 10a, and the first pipe 20 and the second pipe 30 are disposed inside the housing 10, thereby obtaining the silencer 1. [1-3. Actions and Effects] According to the embodiment described above, the following actions and effects can be obtained.

[0065] (1a) In the second pipe arrangement step S140, the second pipe 30 is inserted into the first pipe 20 from the downstream end of the first pipe 20. By inserting in this manner, the second pipe 30 can be easily inserted into the first pipe 20 even if the upstream end of the first pipe 20 is not flared, etc. This improves the ease of assembling the first pipe 20 and the second pipe 30.

[0066] (1b) In the second cylindrical end forming step S130, the second cylindrical end 12 is formed coaxially with the first cylindrical end 11. Due to the diameter reduction that forms the second cylindrical end 12, a second inclined portion 15 is formed in the portion of the cylindrical body 10a adjacent to the second cylindrical end 12. The inner diameter of the second inclined portion 15 decreases from the central portion 13 toward the second cylindrical end 12.

[0067] According to such a configuration of the housing 10 or the cylindrical body 10a, in the second pipe arrangement step S140, the second pipe 30 is guided by the second inclined portion 15, and is thereby easily inserted into the second cylindrical end portion 12. This improves the ease of assembling the second pipe 30 and the second cylindrical end portion 12.

[0068] (1c) The second pipe 30 is inserted into the first pipe 20 from the first large diameter portion 22 of the first pipe 20. The inner diameter of the first large diameter portion 22 is larger than the inner diameter of the first main body portion 21. The first reduced diameter portion 24 connects the first main body portion 21 and the first large diameter portion 22. The inner diameter of the first reduced diameter portion 24 is formed to become smaller as it approaches the first main body portion 21.

[0069] With such a configuration of the first pipe 20, in the second pipe arrangement step S140, it is easy to insert the second pipe 30 into the first pipe 20 from the first large diameter portion 22, and it is easy to insert the second pipe 30 from the first large diameter portion 22 into the first main body portion 21 via the first reduced diameter portion 24. This improves the ease of assembling the first pipe 20 and the second pipe 30.

[0070] (1d) In the first pipe arrangement step S120, the first pipe 20 is inserted into the housing 10 in a state in which the first cylindrical end portion 11 is formed on the housing 10. According to this process, the position of the first pipe 20 is less likely to shift compared to when the first cylindrical end portion 11 is formed after the first pipe 20 is placed inside the housing 10. Therefore, it is possible to suppress the position of the first pipe 20 from shifting.

[0071] Furthermore, there is no need for a member to support the first pipe 20 inside the housing 10 until the first cylindrical end portion 11 is formed. Therefore, the number of types of members required to manufacture the silencer 1 can be reduced.

[0072] (1e) In the second pipe arrangement step S140, the second pipe 30 is inserted into the housing 10 in a state in which the second cylindrical end portion 12 is formed on the housing 10. According to this process, the position of the second pipe 30 is less likely to shift compared to when the second cylindrical end portion 12 is formed after the second pipe 30 is placed inside the housing 10. Therefore, it is possible to suppress the position of the second pipe 30 from shifting.

[0073] Furthermore, there is no need for a member to support the second pipe 30 inside the housing 10 until the second cylindrical end portion 12 is formed. Therefore, the number of types of members required to manufacture the silencer 1 can be reduced.

[0074] (1f) The first connecting portion 21a and the second connecting portion 31 of the first pipe 20, which are the portions where the first pipe 20 and the second pipe 30 are connected, are both located inside the housing 10. The first connecting portion 21a and the second connecting portion 31 are not fixed, and are slidable via the holding member 4.

[0075] With this configuration, both the first pipe 20 and the second pipe 30 can expand and contract in the axial direction when expansion or contraction occurs due to the heat of the exhaust gas. Therefore, excessive load is not applied to the first pipe 20 and the second pipe 30, and buckling can be suppressed.

[0076] (1g) The second connecting portion 31 of the second pipe 30 has a retaining member 4 on its outer surface, which prevents the second pipe 30 from damaging the inner surface of the first pipe 20 during the process of inserting the second pipe 30 into the first pipe 20.

[0077] (1h) After the second pipe arrangement step S140, the first pipe 20 can be fixed to the first cylindrical end portion 11, and the second pipe 30 can be fixed to the second cylindrical end portion 12 by welding, diameter expansion, etc. Therefore, the first pipe 20 and the second pipe 30 can be fixed to the housing 10 more firmly.

[0078] [1-4. Correspondence between terms] In the above embodiment, the upstream end of the first pipe 20 and the first connecting portion 21a correspond to an example of the first end of the first pipe, and the downstream end of the first pipe 20 and the first large diameter portion 22 correspond to an example of the second end of the first pipe.

[0079] The upstream end of the second pipe 30 and the second abutment portion 32 correspond to an example of a first end of the second pipe, and the downstream end of the second pipe 30 and the second connecting portion 31 correspond to an example of a second end of the second pipe.

[0080] The downstream end of the cylindrical body 10a corresponds to an example of a first end of the cylindrical body, and the upstream end of the cylindrical body 10a corresponds to an example of a second end of the cylindrical body. The first cylindrical end forming step S110 corresponds to an example of providing a first cylindrical end, and the first pipe arranging step S120 corresponds to an example of arranging a first end of a first pipe inside the housing. The second cylindrical end forming step S130 corresponds to an example of providing a second cylindrical end, and the second pipe arranging step S140 corresponds to an example of arranging a second pipe. The first cylindrical end forming step S110, the first pipe arranging step S120, and the second cylindrical end forming step S130 correspond to an example of preparing a housing.

[0081] [2. Second Embodiment] [2-1. Silencer configuration] The method for manufacturing the silencer 1 in the second embodiment is to manufacture a silencer 1 similar to that in the first embodiment. Differences between the second embodiment and the first embodiment will be described below. Note that the same reference numerals as in the first embodiment indicate the same configurations, and reference will be made to the preceding description.

[0082] [2-2. Manufacturing method of silencer] As shown in Fig. 5, the method for manufacturing the silencer 1 according to the second embodiment includes a pipe connecting step S210, a first cylindrical end forming step S220, a second cylindrical end forming step S230, and a connecting pipe arranging step S240. The method for manufacturing the silencer 1 according to the second embodiment is performed in the order of the pipe connecting step S210, the first cylindrical end forming step S220, the second cylindrical end forming step S230, and the connecting pipe arranging step S240. However, the order in which the pipe connecting step S210, the first cylindrical end forming step S220, and the second cylindrical end forming step S230 are performed is not particularly limited, and they may be performed in any order. At least two of the pipe connecting step S210, the first cylindrical end forming step S220, and the second cylindrical end forming step S230 may be performed in parallel. Each step will be described with reference to Figs. 6 and 7.

[0083] [2-2-1. Pipe connection process] As shown in FIG. 6, the pipe connecting step S210 is a step of inserting the second pipe 30 into the inside of the first pipe 20, thereby connecting the first pipe 20 and the second pipe 30.

[0084] The second pipe 30 is inserted into the first pipe 20 from the first large diameter portion 22 of the first pipe 20, with the end thereof not provided with the holding member 4 as the front end. After being inserted into the first large diameter portion 22 of the first pipe 20, the front end of the second pipe 30 is guided to the first main body portion 21 by the first reduced diameter portion 24. In this embodiment, the front end of the second pipe 30 corresponds to the second abutment portion 32.

[0085] As the insertion of the second pipe 30 into the first pipe 20 progresses, the second connecting portion 31 and the holding member 4 of the second pipe 30 are inserted inside the first pipe 20. Because the outer diameter of the second connecting portion 31 including the holding member 4 is approximately the same as or slightly larger than the inner diameter of the first pipe 20, the second pipe 30 and the holding member 4 are press-fitted into the first pipe 20. In this embodiment, the press-fitting of the second pipe 30 and the holding member 4 into the first pipe 20 is progressed using a rod-shaped press-fitting jig 5 whose diameter is smaller than the inner diameter of the first pipe 20.

[0086] As the second pipe 30 is further inserted into the first pipe 20, the leading end of the second pipe 30 slips out of the first pipe 20. At this time, the second connecting portion 31 of the second pipe 30 is positioned inside the first pipe 20. In this embodiment, the second connecting portion 31 is positioned inside the first connecting portion 21a, which is located at the end of the first pipe 20 opposite to the first large diameter portion 22.

[0087] In this way, in the pipe connecting step S210, the second abutment portion 32 of the second pipe 30 is disposed outside the first pipe 20. The second connecting portion 31 of the second pipe 30 is disposed inside the first pipe 20. The first pipe 20 and the second pipe 30 are connected.

[0088] [2-2-2. First cylindrical end forming process] As shown in FIG. 7A, the first cylindrical end portion forming step S220 is a step of providing a first cylindrical end portion 11 on a cylindrical body 10a, which is a cylindrical member.

[0089] The first cylindrical end portion forming step S220 is the same as the first cylindrical end portion forming step S110. That is, the first cylindrical end portion 11 is provided by reducing the diameter of the downstream end portion of the cylindrical body 10a.

[0090] Due to the diameter reduction for providing the first cylindrical end portion 11, a first inclined portion 14 is provided in the portion of the cylindrical body 10a adjacent to the first cylindrical end portion 11 on the upstream side. [2-2-3. Second cylindrical end forming process] As shown in FIG. 7B, the second cylindrical end portion forming step S230 is a step of providing the second cylindrical end portion 12 on the cylindrical body 10a.

[0091] The second cylindrical end portion forming step S230 is the same as the second cylindrical end portion forming step S130. That is, the second cylindrical end portion 12 is formed by reducing the diameter of the upstream end portion of the cylindrical body 10a. The second cylindrical end portion 12 is formed approximately coaxially with the first cylindrical end portion 11.

[0092] Due to the diameter reduction for providing the second cylindrical end portion 12, a second inclined portion 15 is provided in the portion of the cylindrical body 10a adjacent to the downstream side of the second cylindrical end portion 12. The housing 10 is obtained by providing the first cylindrical end portion 11 and the second cylindrical end portion 12 to the cylindrical body 10a in this manner.

[0093] [2-2-4. Connecting pipe placement process] 7C, the connecting pipe arrangement step S240 is a step of arranging the connected first pipe 20 and second pipe 30 at least partially inside the cylindrical body 10a. In this step, the first pipe 20 and the second pipe 30 are maintained in a connected state without being separated from each other.

[0094] The second pipe 30 connected to the first pipe 20 is inserted into the cylindrical body 10a from the first cylindrical end 11, with the end not provided with the holding member 4 as the leading end. The leading end of the second pipe 30 is the upstream end of the second pipe 30. In this embodiment, the leading end of the second pipe 30 corresponds to the second abutment portion 32.

[0095] As the connected first pipe 20 and second pipe 30 are inserted further into the tubular body 10a, the upstream end of the first pipe 20 (in this embodiment, the first connecting portion 21a) enters the interior of the tubular body 10a from the first tubular end portion 11.

[0096] 7D, when the second pipe 30 is further inserted into the cylindrical body 10a, the leading end of the second pipe 30 is inserted into the second cylindrical end 12, and the second contact portion 32 is positioned inside the second cylindrical end 12. Furthermore, the first contact portion 22a of the first pipe 20 is positioned inside the first cylindrical end 11. The upstream end of the first pipe 20 is positioned inside the cylindrical body 10a.

[0097] At this time, the upstream end of the second pipe 30 is located inside the second cylindrical end portion 12. The downstream end of the second pipe 30 is located inside the cylindrical body 10a. That is, the second connecting portion 31 and the holding member 4 are located inside the upstream end of the first pipe 20 (i.e., the first connecting portion 21a) located inside the cylindrical body 10a. The downstream end of the first pipe 20 is located inside the first cylindrical end portion 11. However, the upstream end of the second pipe 30 may be located outside the cylindrical body 10a. The downstream end of the second pipe 30 is located inside the first pipe 20 The downstream end of the first pipe 20 may be located outside the cylindrical body 10a.

[0098] In this step or a step thereafter, the first contact portion 22a may be fixed to the first cylindrical end portion 11. The second contact portion 32 may be fixed to the second cylindrical end portion 12. The fixing method may be, for example, at least one of press-fitting, welding, and diameter expansion. In this embodiment, the first contact portion 22a is fixed by being press-fitted into the first cylindrical end portion 11. The second contact portion 32 is fixed to the second cylindrical end portion 12 in a step thereafter.

[0099] In the manner described above, the housing 10 is formed from the cylindrical body 10a, and the first pipe 20 and the second pipe 30, which are connected together, are disposed inside the housing 10, thereby obtaining the silencer 1. [2-3. Actions and Effects] According to the second embodiment described above, the same effects as those of the first embodiment can be obtained. In addition, according to the second embodiment, the provision of the first cylindrical end portion 11 and the second cylindrical end portion 12 to the cylindrical body 10a and the connection of the first pipe 20 and the second pipe 30 can be performed independently of each other. This reduces the number of manufacturing steps.

[0100] [2-4. Correspondence between terms] In the above embodiment, the upstream end of the first pipe 20 and the first connecting portion 21a correspond to an example of a first end of the first pipe.

[0101] The upstream end of the second pipe 30 and the second abutment portion 32 correspond to an example of a first end of the second pipe, and the downstream end of the second pipe 30 and the second connecting portion 31 correspond to an example of a second end of the second pipe.

[0102] The downstream end of the cylindrical body 10a corresponds to an example of a first end of the cylindrical body, and the upstream end of the cylindrical body 10a corresponds to an example of a second end of the cylindrical body. The pipe connecting step S210 corresponds to an example of connecting the first pipe and the second pipe, the first cylindrical end forming step S220 corresponds to an example of providing a first cylindrical end, the second cylindrical end forming step S230 corresponds to an example of providing a second cylindrical end, and the connecting pipe arranging step S240 corresponds to an example of arranging.

[0103] 3. Other Embodiments Although the embodiments of the present disclosure have been described above, it goes without saying that the present disclosure is not limited to the above-described embodiments and can take on various forms.

[0104] (3a) In the above embodiment, the inner circumferential surface of the first connecting portion 21a of the first pipe 20 may be reduced in diameter. The outer circumferential surface of the second connecting portion 31 of the second pipe 30 may be increased in diameter. With this configuration, the retaining member 4 disposed between the inner circumferential surface of the first connecting portion 21a and the outer circumferential surface of the second connecting portion 31 is in a more compressed state. This improves the resistance to vibrations received from a vehicle or the like at the connecting portion between the first pipe 20 and the second pipe 30.

[0105] (3b) In the above embodiment, the upstream end of the second pipe 30 may be reduced in diameter. This configuration makes it easy to insert the second pipe 30 into the second cylindrical end 12 in the second pipe arranging step S140 or the connecting pipe arranging step S240.

[0106] (3c) In the above embodiment, the second contact portion 32 of the second pipe 30 may be expanded in diameter. With this configuration, the second contact portion 32 is fixed to the second cylindrical end portion 12. It is easy to do.

[0107] (3d) In the above embodiment, the first pipe 20 is arranged at the first cylindrical end 11 on the downstream side of the housing 10, and the second pipe 30 is arranged at the second cylindrical end 12 on the upstream side of the housing 10. However, the arrangement of the first pipe 20 and the second pipe 30 is not limited to this, and for example, the first pipe 20 may be arranged at the second cylindrical end 12 on the upstream side of the housing 10, and the second pipe 30 may be arranged at the first cylindrical end 11 on the downstream side of the housing 10.

[0108] (3e) The first cylindrical end 11 and the second cylindrical end 12 are both formed by reducing the diameter of the upstream or downstream end of the cylindrical body 10a. However, instead of reducing the diameter of the cylindrical body 10a, the first cylindrical end 11 and the second cylindrical end 12 may be formed by providing a separate member with a reduced diameter at the upstream or downstream end of the cylindrical body 10a by welding or the like. The separate member may function as the first cylindrical end 11 or the second cylindrical end 12.

[0109] (3f) One or more first through holes 23 are provided in the first pipe 20. One or more second through holes 33 are provided in the second pipe 30. However, it is sufficient that at least one of the first through holes 23 and the second through holes 33 is provided in at least one of the first pipe 20 and the second pipe 30 in the silencer 1. For example, when the first through hole 23 is provided in the first pipe 20, the second pipe 30 does not have to be provided with the second through hole 33. Alternatively, when the second pipe 30 is provided with the second through hole 33, the first pipe 20 does not have to be provided with the first through hole 23.

[0110] (3g) Multiple functions of one component in the above embodiments may be realized by multiple components, or one function of one component may be realized by multiple components. Also, multiple functions of multiple components may be realized by one component, or one function realized by multiple components may be realized by one component. Also, part of the configuration of the above embodiments may be omitted. Also, at least part of the configuration of the above embodiments may be added to or substituted for the configuration of another of the above embodiments.

[0111] [Technical idea disclosed in this specification] [Item 1] A method for manufacturing a silencer, preparing a housing having a central portion and a first cylindrical end portion and a second cylindrical end portion located on both sides of the central portion and having a diameter smaller than that of the central portion, wherein a first pipe is inserted into the first cylindrical end portion and a first end of the first pipe is disposed inside the housing; inserting a second pipe into the first pipe disposed in the housing from the outside of the housing, thereby disposing the second pipe inside the housing; Including, placing the second pipe includes inserting the second pipe from a second end of the first pipe located on the opposite side to the first end of the first pipe, and moving the first end of the second pipe to a position where the second end passes through at least the first end of the first pipe and where the second end of the second pipe located on the opposite side to the first end of the second pipe is disposed inside the first pipe; The silencer is configured to hold the first pipe, to which the second pipe is connected, inside the first cylindrical end. Method for manufacturing silencers.

[0112] [Item 2] A method for manufacturing the silencer according to item 1, and positioning the second pipe includes moving the first end of the second pipe, which is inserted from the second end of the first pipe, at least to the inside of the second cylindrical end so that the second pipe is held inside the second cylindrical end in a state where the second pipe is connected to the first pipe. Method for manufacturing silencers.

[0113] [Item 3] A method for manufacturing the silencer according to item 1, the housing is formed by a first end of a cylindrical body and a second end of the cylindrical body that is located on the opposite side from the first end of the cylindrical body and has a reduced diameter; Providing the housing includes: reducing the diameter of the first end of the cylindrical body to provide the first cylindrical end portion on the cylindrical body; inserting the first pipe into the first cylindrical end portion to position the first end of the first pipe inside the housing; providing the second cylindrical end portion on the cylindrical body by reducing the diameter of the second end portion of the cylindrical body while the first pipe is inserted into the first cylindrical end portion; Including, and positioning the second pipe includes moving the first end of the second pipe, which is inserted from the second end of the first pipe, at least to the inside of the second cylindrical end so that the second pipe is held inside the second cylindrical end in a state where the second pipe is connected to the first pipe. Method for manufacturing silencers.

[0114] [Item 4] A method for manufacturing a silencer, inserting a second pipe into the inside of a first pipe to connect the first pipe and the second pipe so that a first end of the second pipe is disposed outside the first pipe and a second end of the second pipe, which is located on the opposite side to the first end of the second pipe, is disposed inside the first pipe; providing a first cylindrical end portion at a first end of the cylindrical body, the first cylindrical end portion having a diameter smaller than that of the cylindrical body; providing a second cylindrical end portion having a diameter smaller than that of the cylindrical body at a second end of the cylindrical body located opposite to the first end of the cylindrical body; disposing the coupled first pipe and second pipe at least partially within the cylindrical body; Including, the placing includes inserting the second pipe connected to the first pipe into the first cylindrical end portion from the first end of the second pipe, thereby placing at least a portion of the first pipe inside the first cylindrical end portion, placing at least a portion of the second pipe inside the second cylindrical end portion, and placing the first end of the first pipe inside the cylindrical body; The silencer is configured to hold the first pipe inside the first cylindrical end and to hold the second pipe connected to the first pipe inside the second cylindrical end. Method for manufacturing silencers.

[0115] [Item 5] A method for manufacturing a silencer according to item 3 or 4, providing the second cylindrical end portion includes providing the second cylindrical end portion substantially coaxially with the first cylindrical end portion. Method for manufacturing silencers.

[0116] [Item 6] A method for manufacturing a silencer according to any one of items 3 to 5, Providing the second cylindrical end portion includes providing the second cylindrical end portion such that an inner diameter of a portion of the cylindrical body adjacent to the second cylindrical end portion decreases toward the second cylindrical end portion. Method for manufacturing silencers.

[0117] [Item 7] A method for manufacturing a silencer according to any one of items 1 to 6, the second pipe includes a retaining member on an outer peripheral surface of the second end of the second pipe, An outer diameter of the second pipe including the holding member at the second end is equal to or larger than an inner diameter of the first pipe before the second pipe is inserted into the first pipe. Method for manufacturing silencers.

[0118] [Item 8] A method for manufacturing a silencer according to any one of items 1 to 7, the first pipe has a main body portion located between a second end of the first pipe located opposite the first end of the first pipe and the first end of the first pipe, and a reduced diameter portion located between the main body portion and the second end of the first pipe, The inner diameter of the second end of the first pipe is larger than the inner diameter of the main body portion, The inner diameter of the reduced diameter portion is formed to become smaller as it approaches the main body portion. Method for manufacturing silencers. [Explanation of symbols]

[0119] 1... silencer, 10... housing, 10a... cylindrical body, 11... first cylindrical end, 12... second cylindrical end, 13... central portion, 20... first pipe, 21... first main body portion, 21a... first connecting portion, 22... first large diameter portion, 22a... first abutment portion, 30... second pipe, 31... second connecting portion, 32... second abutment portion.

Claims

1. A method for manufacturing a silencer, preparing a housing having a central portion and a first cylindrical end portion and a second cylindrical end portion located on both sides of the central portion and having a diameter smaller than that of the central portion, wherein a first pipe is inserted into the first cylindrical end portion and a first end of the first pipe is disposed inside the housing; inserting a second pipe into the first pipe disposed in the housing from the outside of the housing, thereby disposing the second pipe inside the housing; Including, placing the second pipe includes inserting the second pipe from a second end of the first pipe located opposite to the first end of the first pipe, and moving the first end of the second pipe to a position where the second end passes through at least the first end of the first pipe and where the second end of the second pipe located opposite to the first end of the second pipe is disposed inside the first pipe; The silencer is configured to hold the first pipe, to which the second pipe is connected, inside the first cylindrical end. Method for manufacturing silencers.

2. A method for manufacturing the silencer according to claim 1, and positioning the second pipe includes moving the first end of the second pipe, which is inserted from the second end of the first pipe, at least to the inside of the second cylindrical end so that the second pipe is held inside the second cylindrical end in a state where the second pipe is connected to the first pipe. Method for manufacturing silencers.

3. A method for manufacturing the silencer according to claim 1, the housing is formed by a first end of a cylindrical body and a second end of the cylindrical body that is located on the opposite side from the first end of the cylindrical body and has a reduced diameter; Providing the housing includes: reducing the diameter of the first end of the tubular body to provide the first tubular end portion on the tubular body; inserting the first pipe into the first cylindrical end portion to position the first end of the first pipe inside the housing; providing the second cylindrical end portion on the cylindrical body by reducing the diameter of the second end portion of the cylindrical body with the first pipe inserted into the first cylindrical end portion; Including, and positioning the second pipe includes moving the first end of the second pipe, which is inserted from the second end of the first pipe, at least to the inside of the second cylindrical end so that the second pipe is held inside the second cylindrical end in a state where the second pipe is connected to the first pipe. Method for manufacturing silencers.

4. A method for manufacturing a silencer, inserting a second pipe into the inside of a first pipe to connect the first pipe and the second pipe so that a first end of the second pipe is disposed outside the first pipe and a second end of the second pipe, which is located on the opposite side to the first end of the second pipe, is disposed inside the first pipe; providing a first cylindrical end portion at a first end of the cylindrical body, the first cylindrical end portion having a diameter smaller than that of the cylindrical body; A second end of the cylindrical body located on the opposite side to the first end of the cylindrical body is provided with a providing a second cylindrical end portion having a smaller diameter; disposing the coupled first pipe and second pipe at least partially within the cylindrical body; Including, the placing includes inserting the second pipe connected to the first pipe into the first cylindrical end portion from the first end of the second pipe, thereby placing at least a portion of the first pipe inside the first cylindrical end portion, placing at least a portion of the second pipe inside the second cylindrical end portion, and placing the first end of the first pipe inside the cylindrical body; The silencer is configured to hold the first pipe inside the first cylindrical end and to hold the second pipe connected to the first pipe inside the second cylindrical end. Method for manufacturing silencers.

5. A method for manufacturing the silencer according to claim 3 or claim 4, providing the second cylindrical end portion includes providing the second cylindrical end portion substantially coaxially with the first cylindrical end portion. Method for manufacturing silencers.

6. A method for manufacturing the silencer according to claim 3 or claim 4, Providing the second cylindrical end portion includes providing the second cylindrical end portion such that an inner diameter of a portion of the cylindrical body adjacent to the second cylindrical end portion decreases toward the second cylindrical end portion. Method for manufacturing silencers.

7. A method for manufacturing a silencer according to any one of claims 1 to 4, the second pipe includes a retaining member on an outer peripheral surface of the second end of the second pipe, an outer diameter of the second pipe including the holding member at the second end is equal to or larger than an inner diameter of the first pipe before the second pipe is inserted into the first pipe; Method for manufacturing silencers.

8. A method for manufacturing a silencer according to any one of claims 1 to 4, the first pipe has a main body portion located between the first end of the first pipe and a second end of the first pipe located opposite the first end of the first pipe, and a reduced diameter portion located between the main body portion and the second end of the first pipe, an inner diameter of the second end of the first pipe is larger than an inner diameter of the main body; The inner diameter of the reduced diameter portion is formed to become smaller as it approaches the main body portion. Method for manufacturing silencers.

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