JP2009243388A - Method of manufacturing muffler - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a muffler capable of surely welding a muffler outer cylinder body to a front wall or a rear wall, improving the yield, and capable of flexibly coping even with the case when design of the muffler is changed. <P>SOLUTION: The muffler is manufactured through an insertion process for inserting a muffler core element 20 having partition walls 21 and 22 for partitioning an inside of the muffler outer cylinder body 10 along the longitudinal direction, the front wall 31 for closing a front end of the muffler outer cylinder body 10, and the rear wall 32 for closing a rear end of the muffler outer cylinder body 10 into the inside of the muffler outer cylinder body 10; a pressure-contact process for reducing the muffler outer cylinder body 10 in the diameter and pressure-contacting an inner peripheral surface of the muffler outer cylinder body 10 to outer peripheral surfaces of the partition walls 21 and 22, an outer peripheral surface of the front wall 31, and an outer peripheral surface of the rear wall 32; and a welding process for welding the muffler outer cylinder body 10 at least to the front wall 31 and the rear wall 32. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a muffler manufacturing method including a muffler outer cylinder, a muffler core, a front wall, and a rear wall.

  A muffler called a muffler for reducing exhaust noise is attached to the exhaust pipe of an automobile. Various types of mufflers have been proposed so far, and various devices have been devised to reduce exhaust noise more efficiently. For example, the inside of the muffler outer cylinder is partitioned in the front-rear direction by a partition wall, and the front end and the rear end of the muffler outer cylinder are respectively closed by the front wall and the rear wall (for example, Patent Literature 1).

  In FIG. 5, the inside of the muffler outer cylinder 10 is partitioned in the front-rear direction by partition walls 21 and 22, and the front end and the rear end of the muffler outer cylinder 10 are closed by the front wall 31 and the rear wall 32, respectively. It is sectional drawing which showed the state which cut | disconnected the muffler by the plane containing the central axis of this muffler. The muffler shown in FIG. 5 includes a muffler outer cylinder 10, a front wall 31 for closing the front end of the muffler outer cylinder 10, a rear wall 32 for closing the rear end of the muffler outer cylinder 10, and a muffler. Partition walls 21 and 22 for partitioning the inside of the outer cylindrical body 10 in the front-rear direction, an air guide pipe 23 for introducing exhaust gas derived from the exhaust manifold into the interior of the muffler, and exhaust gas silenced by the muffler to the atmosphere The exhaust pipe 24 is provided.

  In the muffler shown in FIG. 5, the exhaust gas introduced into the inside of the muffler outer cylinder 10 from the air guide tube 23 is attenuated in the resonance frequency component of the vibration in the resonance chamber 51 partitioned by the partition wall 22 and the rear wall 32. After the vibration is attenuated by the first expansion chamber 52 partitioned by the partition wall 22 and the partition wall 21 and the second expansion chamber 53 partitioned by the partition wall 21 and the front wall 31, the vibration passes through the exhaust pipe 24. To be sent to the atmosphere. This makes it possible to effectively reduce engine exhaust noise.

  Manufacturing method of a muffler (see FIG. 5) having a structure in which the inside of the muffler outer cylinder 10 is partitioned in the front-rear direction, and the front end and the rear end of the muffler outer cylinder 10 are closed by the front wall 31 and the rear wall 32, respectively. Is not particularly limited, and is various. For example, after the muffler outer cylinder 10 is formed by winding a metal plate around the outer peripheral surface of the partition walls 21 and 22, the outer peripheral surface of the front wall 31, and the outer peripheral surface of the rear wall 32 in the muffler core body 20, A welding method is known (for example, Patent Documents 2 and 3). This method has the advantage that the number of processes is small. However, on the other hand, a gap is easily formed between the inner peripheral surface of the muffler outer cylindrical body 10 and the outer peripheral surfaces of the partition walls 21 and 22 of the muffler core body 20. There is a drawback that the yield is deteriorated because an excessive portion is inevitably generated in the cylindrical body 10.

  By the way, in Patent Document 4, the openings of a pair of cylinders are overlapped to form an annular overlapped portion around the openings, and substantially the entire periphery of the overlapped portion is pressed in the center direction, and the polymerization is performed. A method for manufacturing a container by laser welding is described, wherein the plurality of members are integrally joined by laser welding of the overlapped portion while maintaining the portion in close contact. This also describes that the overlapped portion can be appropriately laser-welded. However, in this manufacturing method, if the superposed part is to be kept in close contact, the superposed part must be kept pressed. For this reason, it is necessary to incorporate a pressing means for pressing the overlapped portion and a welding means for laser welding the overlapped portion in the same apparatus. Therefore, the versatility of the apparatus is low, and there is a drawback that it is difficult to cope with a case where the design of the muffler is changed.

JP 2002-021549 A JP 2003-138935 A JP 2006-266215 A JP 2005-153015 A

  The present invention has been made to solve the above-mentioned problems, and not only more reliably welds the muffler outer cylinder to the front wall and the rear wall, but also improves the yield, and further, the muffler has a design change. It is an object of the present invention to provide a muffler manufacturing method that can flexibly cope with such cases.

The above issues
A muffler core body having a partition wall for partitioning the inside of the muffler outer cylinder in the front-rear direction, a front wall for closing the front end of the muffler outer cylinder, and a rear end of the muffler outer cylinder An insertion step of inserting the rear wall into the inside of the muffler outer cylinder,
A pressure-contacting step of contracting the muffler outer cylinder to press-contact the inner peripheral surface of the muffler outer cylinder to the outer peripheral surface of the partition wall, the outer peripheral surface of the front wall, and the outer peripheral surface of the rear wall;
A welding step of welding the muffler outer cylinder to at least the front wall and the rear wall;
It is solved by providing a method of manufacturing a muffler characterized by undergoing

  Thus, by contracting the muffler outer cylinder, the muffler outer cylinder, the muffler core, the front wall and the rear wall can be fixed to each other and completely positioned, so Makes it possible to carry out the welding process in other different places. Therefore, the versatility of the device can be improved, and even when the design of the muffler is changed, it can be easily handled. In addition, the muffler outer cylinder can be reliably welded to the front wall and the rear wall.

  In the welding process, it is preferable that the muffler outer cylinder is welded not only to the front wall and the rear wall but also to the partition wall. From the standpoint of improving the muffler's noise reduction performance, the muffler outer cylinder and the front wall, and the muffler outer cylinder and the partition wall are required to be airtight, if not as much as the muffler outer cylinder and rear wall. Because.

  The contraction means for contracting the muffler outer cylinder in the press-contacting process is not particularly limited, but a plurality of pressing segments for pressing the outer peripheral surface of the muffler outer cylinder from the outside of the muffler outer cylinder toward the center It is preferable that it is a split mold provided with. The welding method in the welding process is not particularly limited, but the welding in the welding process is preferably laser welding, electron beam welding, or plasma welding.

  As described above, according to the present invention, not only the muffler outer cylinder body is more reliably welded to the front wall and the rear wall, but also the yield is improved, and further, the design of the muffler is changed. It is also possible to provide a method of manufacturing a muffler that can be flexibly adapted.

  A preferred embodiment of the method for producing a muffler of the present invention will be described more specifically with reference to the drawings. FIG. 1 is a perspective view showing the muffler when the muffler core body 20, the front wall 31, and the rear wall 32 are inserted into the muffler outer cylinder 10. FIG. 2 is a perspective view showing the muffler after the muffler core body 20, the front wall 31, and the rear wall 32 are inserted into the muffler outer cylinder 10. FIG. 3 is a front view showing the muffler when the muffler outer cylinder 10 is contracted. FIG. 4 is a perspective view showing the muffler after the muffler outer cylinder 10 is welded to the front wall 31 and the rear wall 32.

1. Outline of Muffler Manufacturing Method The muffler manufacturing method of the present invention is a muffler core body provided with partition walls 21 and 22 for partitioning the inside of the muffler outer cylinder 10 in the front-rear direction, as shown in FIGS. 20, an insertion step of inserting the front wall 31 for closing the front end of the muffler outer cylinder 10 and the rear wall 32 for closing the rear end of the muffler outer cylinder 10 into the inside of the muffler outer cylinder 10. (See FIGS. 1 and 2), the muffler outer cylinder 10 is contracted, and the inner peripheral surface of the muffler outer cylinder 10 is divided into the outer peripheral surfaces of the partition walls 21 and 22, the outer peripheral surface of the front wall 31, and the rear wall 32. The muffler is manufactured through a pressure-contacting process (see FIG. 3) for press-contacting with the outer peripheral surface of the muffler and a welding process (see FIG. 4) for welding the muffler outer cylinder 10 to at least the front wall 31 and the rear wall 32. It is supposed to be.

2. Muffler Before specifically explaining the muffler manufacturing method of the present invention, each component constituting the muffler manufactured by the muffler manufacturing method of the present invention will be described. The muffler manufacturing method of the present embodiment is to manufacture a muffler by combining and combining the muffler outer cylinder 10, the muffler core body 20, the front wall 31, and the rear wall 32.

3. Muffler outer cylinder body The muffler outer cylinder body 10 used in the muffler manufacturing method of the present invention can insert the muffler core body 20, the front wall 31, and the rear wall 32 (muffler core body partition walls 21, 22 and As long as it has a cylindrical shape (having an inner diameter larger than the outer diameter of the front wall 31 and the rear wall 32), the shape (the shape of the cross section perpendicular to the longitudinal direction) is not particularly limited. The shape of the muffler outer cylinder 10 is appropriately determined according to the type of the muffler. Examples of the muffler outer cylinder 10 include a round cross-section and an elliptical cross-section. In the muffler manufacturing method of this embodiment, the muffler outer cylinder 10 is an elliptical cross section.

The inner diameter of the muffler outer cylinder 10 varies depending on the outer diameters of the partition walls 21 and 22, the front wall 31, and the rear wall 32 of the muffler core 20, and is not particularly limited. This is because when the muffler core 20, the front wall 31, and the rear wall 32 are inserted into the muffler outer cylinder 10, the inner peripheral surface of the muffler outer cylinder 10, the muffler core 20 and the front wall are arranged. 31 and the outer peripheral surface of the rear wall 32 (the outer peripheral surfaces of the partition walls 21 and 22) (hereinafter referred to as “gap G ₁ ”) must be secured to a certain extent. There is a risk that it will be difficult to insert the muffler core 20, the front wall 31, and the rear wall 32 inside, and conversely, if the gap G ₁ is too wide, the distortion of the muffler outer cylinder 10 during the contraction process will be reduced. This is because not only the appearance of the obtained muffler is deteriorated but also the dimensional accuracy of the product may be lowered. Specific values of the inner diameter of the muffler outer cylinder 10 will be described later.

  The thickness of the peripheral wall of the muffler outer cylinder 10 varies depending on the dimensions and material of the muffler outer cylinder 10 and is not particularly limited. However, if the peripheral wall of the muffler outer cylinder 10 is too thin, not only the strength of the muffler outer cylinder 10 cannot be maintained, but noise may easily leak to the outside of the muffler. For this reason, the thickness of the peripheral wall of the muffler outer cylinder 10 is normally set to 0.3 mm or more. The thickness of the peripheral wall of the muffler outer cylinder 10 is preferably 0.5 mm or more, and more preferably 0.7 mm or more.

  On the other hand, if the peripheral wall of the muffler outer cylinder 10 is too thick, the muffler outer cylinder 10 is not easily contracted, and the muffler outer cylinder 10 and the front wall 31 are connected from the outside of the muffler outer cylinder 10. It may be difficult to perform welding, welding of the muffler outer cylinder 10 and the rear wall 32, or welding of the muffler outer cylinder 10 and the muffler core body 20. In addition, the muffler outer cylinder 10 may be too heavy. For this reason, the thickness of the peripheral wall of the muffler outer cylinder 10 is normally set to 5 mm or less. The thickness of the peripheral wall of the muffler outer cylinder 10 is preferably 3 mm or less, and more preferably 2 mm or less. In the muffler manufacturing method of this embodiment, the thickness of the peripheral wall of the muffler outer cylinder 10 is about 1 mm.

  As the material of the muffler outer cylinder 10, the muffler core 20, the front wall 31, and the rear wall 32, the same metal as that used for a general muffler can be adopted. The muffler outer cylinder body 10, the muffler core body 20, the front wall 31, and the rear wall 32 may be formed of different kinds of metals, but considering that they are welded to each other, it is preferable to use the same kind of material. . Also in the manufacturing method of the muffler of this embodiment, the muffler outer cylinder 10, the muffler core 20, the front wall 31, and the rear wall 32 are made of the same kind of stainless steel. This makes it possible to make the muffler lightweight and excellent in heat resistance and corrosion resistance.

  The specific type of stainless steel used to form the muffler outer cylinder 10, the muffler core 20, the front wall 31, and the rear wall 32 is not particularly limited. Examples include ferritic stainless steels such as SUS409, SUH409, SUS429, SUS430, SUS432, and SUS444, and austenitic stainless steels such as SUSXM15J1. In the muffler manufacturing method of the present embodiment, the muffler outer cylinder 10, the front wall 31, and the rear wall 32 are formed of SUS432 having excellent corrosion resistance, and the partition walls 21 and 22, the air guide tube 23, and the exhaust in the muffler core body 20. The tube 24 is made of SUS409 that has excellent strength at high temperatures.

  The muffler outer cylinder 10 may be a seamless pipe having excellent strength. However, in the case of a vehicle muffler, a welded pipe (a pipe obtained by bending a metal plate into a cylindrical shape and welding its overlapping portion) However, the strength can be fully demonstrated. For this reason, in the muffler manufacturing method of this embodiment, a welded pipe is used as the muffler outer cylinder 10. This also makes it possible to reduce the manufacturing cost of the muffler.

4). Muffler core body The muffler core body 20 is not particularly limited as long as it has at least one partition wall. In the muffler manufacturing method of this embodiment, the muffler core body 20 has two partition walls 21 and 22 perpendicular to the longitudinal direction of the muffler core body 20. The interior can be partitioned into three chambers arranged in the front-rear direction.

  In the muffler manufacturing method of the present embodiment, the space 51 partitioned by the rear partition wall 22 and the rear wall 32 inside the muffler outer cylinder 10 is a resonance chamber. A space 52 partitioned by the front partition wall 21 and the rear partition wall 22 inside the muffler outer cylinder 10 is a first expansion chamber. Furthermore, a space 53 partitioned by the front partition wall 21 and the front wall 31 inside the muffler outer cylinder 10 is a second expansion chamber. The partition wall 22 is provided with a through-hole for communicating the resonance chamber 51 and the first expansion chamber 52. The partition wall 21 communicates the first expansion chamber 52 and the second expansion chamber 53. A through hole is provided for this purpose.

  The partition wall 21 and the partition wall 22 are connected to each other via an air guide pipe 23 and an exhaust pipe 24, and the muffler core 20 includes the partition wall 21, the partition wall 22, the air guide pipe 23, and the exhaust pipe 24. It has an integrated structure. The air guide pipe 23 is for introducing exhaust gas led out from an exhaust manifold (not shown) into the resonance chamber 51 inside the muffler outer cylinder 10. One exhaust pipe 24 is for sending the exhaust gas reaching the second expansion chamber 53 to the atmosphere.

  For this reason, the exhaust gas led out from the exhaust manifold is introduced into the muffler by the air guide pipe 23, and mainly the low frequency region sound is removed in the resonance chamber 51, and the first expansion chamber 52, the second expansion chamber 53, Then, after the sound in the other frequency region is removed, the sound is sent to the atmosphere through the exhaust pipe 24.

The outer diameter of the muffler core body 20 (the outer diameter of the partition walls 21 and 22) varies depending on the inner diameter of the muffler outer cylinder 10 and the like, and is not particularly limited. However, when the muffler core body 20 is inserted into the muffler outer cylinder body 10, the inner circumferential surface of the muffler outer cylinder body 10 and the outer circumferential surface of the muffler core body 20 (the outer circumferential surfaces of the partition walls 21 and 22). If the gap (hereinafter referred to as “gap G ₂ ”) is too small, it may be difficult to insert the muffler core body 20 inside the muffler outer cylinder 10. Therefore, the outer diameter of the muffler core body 20, it is usually preferred to a value which can ensure the gap _{G 2} or 0.3 mm. The outer diameter of the muffler core body 20 is preferably when the value which can ensure the gap _{G 2} or 0.4 mm, and more preferably a value which can ensure more 0.5 mm.

On the other hand, when the muffler core body 20 is inserted into the muffler outer cylinder body 10, the inner peripheral surface of the muffler outer cylinder body 10 and the outer peripheral surface of the muffler core body 20 (the outer peripheral surfaces of the partition walls 21 and 22). When the gap G ₂ is too large, the distortion of the muffler outer cylindrical body 10 is increased by condensation tube, not only the appearance of the muffler obtained is deteriorated dimensional accuracy of the product is also likely to deteriorate. For this reason, the outer diameter of the muffler core body 20 (the outer diameter of the partition walls 21 and 22) is normally set so that the gap G2 does not exceed ₂ mm. The outer diameter of the muffler core body 20 preferably by setting so that a gap G ₂ does not exceed 1.5 mm, and more preferably set to no more than 1 mm.

In the muffler manufacturing method of the present embodiment, the cross-sectional shape (the cross-sectional shape perpendicular to the longitudinal direction of the muffler outer cylinder 10) of the muffler outer cylinder 10 before the contraction process is It has a substantially elliptical shape with a length (major axis) of 175 mm and a minor axis length (minor axis) of 87 mm. In contrast, the cross-sectional shape of the outer peripheral surfaces of the partition walls 21 and 22 of the muffler core body 20 (the cross-sectional shape perpendicular to the longitudinal direction of the muffler core body 20) has a long axis length (long diameter) of 173 mm. The minor axis has a substantially elliptical shape with a minor axis length of 85 mm. Therefore, when the muffler core body 20 is inserted into the muffler outer cylinder body 10, the inner peripheral surface of the muffler outer cylinder body 10 and the outer peripheral surface of the muffler core body 20 (the outer peripheral surfaces of the partition walls 21 and 22) gap _{G 2} of is of the order of 0.5~1mm.

  The thickness of the partition walls 21 and 22 varies depending on the material and the like and is not particularly limited. However, if the partition walls 21 and 22 are too thin, the strength of the partition walls 21 and 22 may be reduced, and the partition walls 21 and 22 may be deformed when the muffler outer cylinder 10 is contracted. For this reason, the thickness of the partition walls 21 and 22 is normally 0.3 mm or more. The thickness of the partition walls 21 and 22 is preferably 0.5 mm or more, and more preferably 0.7 mm or more.

  On the other hand, if the partition walls 21 and 22 are too thick, the muffler may be too heavy. For this reason, the thickness of the partition walls 21 and 22 is normally 5 mm or less. The thickness of the partition walls 21 and 22 is preferably 3 mm or less, and more preferably 2 mm or less. In the muffler manufacturing method of this embodiment, the thickness of the partition walls 21 and 22 is about 1 mm.

5. Front wall and rear wall The front wall 31 serves to close the front end of the muffler outer cylinder 10, and the rear wall 32 serves to close the rear end of the muffler outer cylinder 10. Yes. The front wall 31 and the rear wall 32 may be formed separately from the muffler core body 20, but in the muffler manufacturing method of the present embodiment, the front wall 31 and the rear wall 32 are integrally attached to the muffler core body 20. The structure is possible. Therefore, as will be described later, the front wall 31 and the rear wall 32 can be inserted into the muffler outer cylinder 10 simultaneously with the muffler core body 20 in the insertion step. The outer diameter of the front wall 31 and the rear wall 32 (the gap between the inner peripheral surface of the muffler outer cylindrical body 10 and the outer peripheral surface of the front wall 31 when the front wall 31 and the rear wall 32 are inserted into the muffler outer cylindrical body 10. (Hereinafter referred to as “gap G ₃ ”), a gap between the inner peripheral surface of the muffler outer cylinder 10 and the outer peripheral surface of the rear wall 32 (hereinafter referred to as “gap G ₄ ”)), Since the thickness and the material are the same as those of the partition walls 21 and 22 in the muffler core body 20, description thereof is omitted.

6). Next, the muffler manufacturing method of the present invention will be specifically described for each step. The muffler manufacturing method of the present invention manufactures a muffler through an insertion process, a pressure welding process, and a welding process.

7). Insertion Step First, the insertion step will be described. In the insertion step, as shown in FIGS. 1 and 2, a muffler core body 20 provided with partition walls 21 and 22 for partitioning the inside of the muffler outer cylinder body 10 in the front-rear direction, and the front end of the muffler outer cylinder body 10 And a rear wall 32 for closing the rear end of the muffler outer cylinder 10 are inserted into the muffler outer cylinder 10.

  The front wall 31 and the rear wall 32 may be inserted separately after the muffler core body 20 is inserted into the muffler outer cylinder 10. However, in the muffler manufacturing method of this embodiment, the front wall 31 and the rear wall 32 are respectively attached to predetermined locations in the muffler core body 20 (in the vicinity of the pipe ends of the air guide pipe 23 and the exhaust pipe 24 in the example of FIG. 1), and the front wall 31 and the rear wall 32 are integrated with the muffler core body 20 in advance. It is trying to insert in the state that became. Thereby, the insertion operation | work of the muffler core 20, the front wall 31, and the rear wall 32 can be performed at once.

  When the muffler core body 20, the front wall 31 and the rear wall 32 are inserted into the muffler outer cylinder body 10, as described above, the inner peripheral surface of the muffler outer cylinder body 10 and the partition wall 21 of the muffler core body 20. , 22 and between the inner peripheral surface of the muffler outer cylinder 10 and the outer peripheral surface of the front wall 31 and the outer peripheral surface of the rear wall 32, gaps of about 0.5 to 1 mm are generated, respectively. Therefore, the muffler core body 20, the front wall 31, and the rear wall 32 can be easily inserted into the muffler outer cylinder 10.

  The muffler that has finished the insertion process is set inside a split mold 40 to be described later, and proceeds to the pressure welding process.

8). Pressure welding process In the pressure welding process, as shown in FIG. 3, the muffler outer cylinder 10 is contracted, and the inner peripheral surface of the muffler outer cylinder 10 is divided into partitions 21 and 22 of the muffler core 20 (see FIG. 2). The outer peripheral surface of the front wall 31, the outer peripheral surface of the front wall 31, and the outer peripheral surface of the rear wall 32 (see FIG. 2) are pressed against each other, and the muffler outer cylinder 10, the muffler core body 20, the front wall 31, and the rear wall 32 Are fixed to each other. At this time, the muffler outer cylinder 10, the muffler core 20, the front wall 31, and the rear wall 32 are in a state of being firmly positioned with respect to each other.

  The contraction means for contracting the muffler outer cylinder 10 is a contraction of the muffler outer cylinder 10 so that the inner periphery of the muffler outer cylinder 10 is the outer periphery of the partition walls 21 and 22 in the muffler core 20. There is no particular limitation as long as it can be brought into pressure contact with the outer peripheral surface of the front wall 31 and the outer peripheral surface of the rear wall 32. In the muffler manufacturing method of this embodiment, the split mold 40 shown in FIG. 3 is used as the tube contraction means. The split mold 40 includes a plurality of pressing segments 41 to 48 for pressing the outer peripheral surface of the muffler outer cylinder 10 from the outside of the muffler outer cylinder 10 toward the center.

The number of the pressing segments 41 to 48 in the split mold 40 varies depending on the cross-sectional shape of the muffler and is not particularly limited, but is 8 in the muffler manufacturing method of the present embodiment. The central angles of the pressing segments 41 to 48 (（P ₁ CP ₂ , ∠P ₂ CP ₃ , ∠P ₃ CP ₄ , ∠P ₄ CP ₅ , ∠P ₅ CP ₆ , ∠P ₆ CP ₇ , ∠P ₇ CP ₈ and ∠P ₈ CP ₁ ) are set equal at 45 °. Each of the pressing segments 41 to 48 is a cam slider, and is moved by a cam driver (not shown) that moves along the longitudinal direction of the muffler outer cylinder 10 while contacting the outer peripheral surface of the pressing segments 41 to 48 (split mold 40). It slides in the direction of the thick arrow shown in FIG. The gap between adjacent pressing segments 41 to 48 when moved inward is about 2 mm.

  When the cam driver moves and the pressing segments 41 to 48 of the split mold 40 move inward, the partition walls 21, 22, the front wall 31, and the rear wall 32 are forced toward the center from their outer peripheral surfaces. Will be added. The partition walls 21, 22, the front wall 31, and the rear wall 32 are not easily deformed by a force in a direction along the wall surface, and firmly support the muffler outer cylinder 10 from the inside. For this reason, the muffler outer cylinder 10 is in a state of being strongly tightened with respect to the partition walls 21 and 22, the front wall 31, and the rear wall 32.

After the pressing segments 41 to 48 reach the inner dead point (when the pressing segments 41 to 48 cannot move further inside), the pressing segments 41 to 48 are moved backward to the inside of the split mold 40. Even if the muffler is taken out of the muffler, the inner peripheral surface of the muffler outer cylinder 10 is pressed against the outer peripheral surfaces of the partition walls 21 and 22 of the muffler core 20, the outer peripheral surface of the front wall 31, and the outer peripheral surface of the rear wall 32. The muffler outer cylinder body 10, the muffler core body 20, the front wall 31, and the rear wall 32 are fixed to each other. As shown in FIG. 4, the muffler that has finished the press-contacting process includes boundary lines between adjacent pressing segments 41 to 48 in the split mold 40 (eight vertical to the paper surface passing through the points Q _{1 to} Q ₈ in FIG. 3). Wrinkles are formed along a straight line.

  The muffler that has finished the pressure welding process is taken out from the split mold 40 and proceeds to a welding process described later.

9. Welding process In the welding process, the muffler outer cylinder 10 and the front wall 31 and the rear wall 32 are welded to integrate the muffler outer cylinder 10, the front wall 31 and the rear wall 32. In the muffler manufacturing method of this embodiment, not only the muffler outer cylinder 10 and the front wall 31 and the rear wall 32 but also the muffler outer cylinder 10 and the muffler core body 20 are welded in the welding process. Yes.

  The welding method between the muffler outer cylinder 10 and the front wall 31 and the rear wall 32 and the welding method between the muffler outer cylinder 10 and the muffler core body 20 in the welding process are not particularly limited. Depending on the material of the muffler outer cylinder 10 and the thickness of its peripheral wall, arc welding or the like can be adopted, but laser welding, electron beam welding, and plasma welding are preferable from the viewpoint of the penetration depth. In laser welding, electron beam welding, and plasma welding, even if the penetration is deep and the peripheral wall of the muffler outer cylinder 10 is thick, from the outside of the muffler outer cylinder 10, the muffler outer cylinder 10 and the muffler core 20 and the muffler This is because the outer cylindrical body 10 and the front wall 31 and the muffler outer cylindrical body 10 and the rear wall 32 can be firmly welded.

  In the muffler manufacturing method of this embodiment, welding between the muffler outer cylinder 10 and the front wall 31 and the rear wall 32 and welding between the muffler outer cylinder 10 and the muffler core body 20 are performed by laser welding. . Laser welding has the advantages that the heat input is small and thermal distortion can be prevented and that no spatter is generated, so that the appearance of the muffler can be finished beautifully. Laser welding can maintain the strength of the welded part even in the atmosphere by spraying the welded part with argon gas, helium gas, or nitrogen gas as a shielding gas. Laser welding does not require a vacuum chamber to be incorporated in the manufacturing facility unlike electron beam welding, so that it is possible to respond flexibly even when the design of the muffler is changed.

  The welding location of the muffler outer cylinder 10 and the front wall 31 and the rear wall 32 is not particularly limited. The overlapping portion of the outer peripheral surface of the muffler outer cylindrical body 10 with the outer peripheral surface of the front wall 31 (shaded portion 10A in FIG. 4) and the overlapping portion of the outer peripheral surface of the muffler outer cylindrical body 10 with the outer peripheral surface of the rear wall 32 (see FIG. 4 may be welded only partially. However, from the viewpoint of improving the muffler muffler performance, it is necessary to improve the air tightness of the muffler outer cylinder 10 and the front wall 31 and the muffler outer cylinder 10 and the rear wall 32. 10 and the front wall 31 and the rear wall 32 are preferably welded over the entire circumference of the overlapping portions 10A and 10D.

  The welding location of the muffler outer cylinder 10 and the muffler core body 20 is not particularly limited. For example, an overlapping portion (shaded portion 10B in FIG. 4) of the outer peripheral surface of the muffler outer cylindrical body 10 with the outer peripheral surface of the front partition wall 21 or the outer periphery of the rear partition wall 22 on the outer peripheral surface of the muffler outer cylindrical body 10 You may weld the overlapping part (shaded part 10C in FIG. 4) with a surface over a perimeter part, respectively. In the muffler manufacturing method of this embodiment, since the overlapping portions 10B and 10C are not required to be as airtight as the overlapping portions 10A and 10B, only a part thereof is welded. Thereby, the time of a welding process can be shortened.

  By the way, in the manufacturing method of the muffler of this embodiment, the pressure welding process and the welding process are performed in different places. That is, when the pressure welding process is completed, the muffler is taken out from the split mold 40 (contracting means), and the muffler is transferred to another place before performing the welding process. Thus, it is possible to enhance the versatility of the muffler manufacturing facility by performing the pressure welding process and the welding process at different locations. In addition, since the welding process can be performed on another muffler while the pressure contact process is performed on one muffler, it is possible to increase the efficiency of manufacturing the muffler.

10. Application The muffler production method of the present invention can be used to produce various mufflers. Especially, it is suitable as what manufactures the muffler for vehicles connected to the exhaust manifold of a motor vehicle or a motorcycle.

It is the perspective view which showed the muffler when the muffler core body, the front wall, and the rear wall are inserted into the muffler outer cylinder. It is the perspective view which showed the muffler after inserting the muffler core body, the front wall, and the rear wall into the muffler outer cylinder. It is the front view which showed the muffler when contracting the muffler outer cylinder. It is the perspective view which showed the muffler after welding the muffler outer cylinder to the front wall and the rear wall. A conventional muffler in which the inside of the muffler outer cylinder is partitioned in the front-rear direction by a partition wall, and the front end and the rear end of the muffler outer cylinder are closed by the front wall and the rear wall, respectively, in a plane including the central axis of the muffler. It is sectional drawing which showed the state cut | disconnected.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Muffler outer cylinder body 20 Muffler core body 21 Partition wall 22 Partition wall 23 Air guide pipe 24 Exhaust pipe 30 Closure means 31 Front wall 32 Rear wall 40 Split type (constriction means)
41 Pressing segment 42 Pressing segment 43 Pressing segment 44 Pressing segment 45 Pressing segment 46 Pressing segment 46 Pressing segment 47 Pressing segment 48 Pressing segment 51 Resonance chamber (space partitioned by a rear partition wall and a rear wall inside the muffler outer cylinder)
52 1st expansion chamber (space divided by the front side partition wall and the rear side partition wall inside the muffler outer cylinder)
53 Second Expansion Chamber (Space partitioned by a front partition wall and a front wall inside the muffler outer cylinder)

Claims (4)

A muffler core body having a partition wall for partitioning the inside of the muffler outer cylinder in the front-rear direction, a front wall for closing the front end of the muffler outer cylinder, and a rear end of the muffler outer cylinder An insertion step of inserting the rear wall into the inside of the muffler outer cylinder,
A pressure-contacting step of contracting the muffler outer cylinder to press-contact the inner peripheral surface of the muffler outer cylinder to the outer peripheral surface of the partition wall, the outer peripheral surface of the front wall, and the outer peripheral surface of the rear wall;
A welding step of welding the muffler outer cylinder to at least the front wall and the rear wall;
A process for producing a muffler, characterized in that   The muffler manufacturing method according to claim 1, wherein a muffler outer cylinder is also welded to the partition wall in the welding step.   The muffler according to claim 1 or 2, wherein the contraction in the press-contacting process is performed using a split mold provided with a plurality of pressing segments for pressing the outer peripheral surface of the muffler outer cylindrical body from the outside of the muffler outer cylinder toward the center. Manufacturing method.   The manufacturing method of the muffler in any one of Claims 1-3 which performs welding in a welding process by laser welding, electron beam welding, or plasma welding.

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