JP2008169752A - Exhaust system part and method of manufacturing exhaust system part - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust system part and a manufacturing method of the exhaust system part, capable of forming an exhaust gas extension passage with a simple structure. <P>SOLUTION: In a muffler inlet member 10, an upper side superposing object part 68 and a lower side superposing object part 70 are formed in an outer peripheral part of an opening end 44B of a high speed gas passage forming part 44 in a base 62, and a step 74 turning to the opening end 44B side is formed in a forming range of the lower side superposing object part 70 in the opening end 44B. A lower half 66 is superposed on the lower side superposing object part 70 in one end part, and is butted against the step 74, and is welded to the step 74. An upper half 64 is superposed on the upper side superposing object part 68 in one end part, and is welded to an outer peripheral surface of the high speed gas passage forming part 44. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an exhaust system component provided in a vehicle such as an automobile and a method for manufacturing the exhaust system component.

A first outlet pipe for discharging exhaust gas during high-speed operation of the engine, a second outlet pipe for discharging exhaust gas during low-speed operation of the engine, and a valve provided to open and close the first outlet pipe A vehicle muffler having the following is known.
JP 2006-125232 A

  For example, when the valve is disposed on the inlet side of the muffler, an extension for forming a flow path for introducing exhaust gas into the muffler when the valve is closed and for making the opening portion of the flow path and the flow path where the valve is installed different. A road is needed.

  An object of the present invention is to obtain an exhaust system component capable of forming an exhaust gas extension path with a simple structure and a method for manufacturing the exhaust system component in consideration of the above facts.

  The exhaust system component according to the first aspect of the present invention includes a polymerized portion formed on an outer periphery of an opening end portion of an exhaust gas passage formed inside, and an end portion in the exhaust gas flow direction with respect to the polymerized portion. A base material having a step portion formed in a part of the circumferential direction facing the polymerized portion side, and one end portion of the exhaust gas flow direction in the circumferential direction in which the step portion in the polymerized portion is formed And the first member that is abutted against and joined to the stepped portion, and one end portion in the exhaust gas flow direction is the stepped portion in the circumferential direction of the polymerized portion of the base material And is joined to the outer peripheral surface of the base material, and both end portions in the circumferential direction are joined to both end portions in the circumferential direction of the first member, and the first member An exhaust gas extension passage having a closed cross-sectional structure continuous with the gas passage is formed. It includes 2 and member.

  In the exhaust system component according to claim 1, the outer periphery of the opening end portion of the exhaust gas flow path in the base material is a polymerized portion over a predetermined range in the exhaust gas flow direction, and A step portion facing the opening end side (polymerized portion side) is formed along an end portion (edge portion) opposite to the opening end. One end portion of the first member is overlapped with the stepped portion forming range on the surface to be polymerized of the base material, and the end surface is joined to the stepped portion while being abutted against the stepped portion. On the other hand, the second member is a state where the end surface facing the opposite side of the open end of the base material is an outer peripheral surface of the base material in a state where the second member is overlapped mainly in a range where the first member is not overlapped on the surface to be polymerized. It is joined to. Then, by joining the circumferential end portions of the first member and the second member, an exhaust gas extension passage having a closed cross-sectional structure that is continuous (communication) with the exhaust gas passage is formed.

  Here, the step portion to which the end surface of the first member is joined faces the opening end side of the base material, and the end surface of the second member joined to the outer peripheral surface of the base material is opposite to the opening end of the base material. Therefore, the direction of joining (working) the first member to the substrate and the direction of joining the second member to the substrate can be different directions. Thereby, when forming the exhaust gas extension path which continues to the exhaust gas flow path of the base material, it becomes possible to perform the joining operation while avoiding obstacles, for example.

  Thus, in the exhaust system component according to the first aspect, the exhaust gas extension path can be formed with a simple structure.

  An exhaust system component according to a second aspect of the present invention is the exhaust system component according to the first aspect, wherein a portion of the polymerized portion where the first member is superimposed is overlapped with the second member of the polymerized portion. The portion to be formed is recessed by the thickness of the first member, and both end portions in the circumferential direction of the second member are overlapped and joined to both end portions in the circumferential direction of the first member.

  In the exhaust system part according to claim 2, since the portion where the first member is overlapped in the polymerized portion of the base material is recessed by the thickness of the first member, both end portions in the circumferential direction of the second member are It is possible to superimpose and join both ends of one member in the circumferential direction. Thereby, excessive dimensional accuracy is not requested | required of each member, and welding quality is easy to be ensured.

  According to a third aspect of the present invention, there is provided the exhaust system component according to the first or second aspect, wherein the base material includes a first opening that is an opening of the exhaust gas passage, A second opening is formed adjacent to the first opening, and the step is formed on the second opening side of the first opening.

  In the exhaust system component according to claim 3, the first member cannot be joined from the side opposite to the opening end by the second opening portion, but has a step portion facing the opening end side. And the end of the first member can be joined well.

  An exhaust system component according to a fourth aspect of the present invention is the exhaust system component according to the third aspect, wherein the exhaust gas extension passage passes through the first expansion chamber of the muffler and opens to the final expansion chamber, and A muffler inlet member having two openings opened in the first expansion chamber.

  In the exhaust system component according to claim 4, an exhaust gas extension path is formed by the first member and the second member in order to open a flow path in which two openings are continuous in different expansion chambers in the muffler. As a result, the second opening to which the exhaust gas extension path is not connected opens in the first extension chamber, and the exhaust gas flow path in which the exhaust gas extension path is connected to the first opening passes through the exhaust gas extension path. Open to the final expansion chamber. Thus, the structure of the present invention is suitably applied to the muffler position port member having a branch on the inlet side.

  According to a fifth aspect of the present invention, there is provided an exhaust system component manufacturing method comprising: a polymerized portion formed on an outer periphery of an opening end portion of an exhaust gas passage formed therein; and an exhaust gas flow direction relative to the polymerized portion A base material preparation step of preparing a base material having a step portion formed facing a portion to be polymerized in a part of a circumferential direction at an end portion; and an end portion of the first member in the exhaust gas flow direction A first joining step that abuts the stepped portion of the material and overlaps the polymerized surface, and welds one end of the first member to the stepped portion; and one end of the second member in the exhaust gas flow direction A second joining step in which the first member on the polymerized surface of the material is superposed on a range where the first member is not superposed, and one end of the second member is welded to the outer peripheral surface of the base material; and the base in the first member Both ends in the circumferential direction of the material, and in the circumferential direction of the base material in the second member And a third joining step of welding the end portion.

  In the exhaust system component manufacturing method according to claim 5, the first member is welded in the first joining step, the second member is welded in the second joining step, and the second member is welded to the base material prepared in the base material preparing step. In the 3 joining step, the first member and the second member are welded. Here, in this manufacturing method, the step part to which the end surface of the first member in the base material is joined faces the opening end side of the base material, and the end surface of the second member to be joined to the outer peripheral surface of the base material is Since it faces away from the open end of the substrate, the welding direction of the first member to the substrate (the approach of the welding torch) and the welding direction of the second member to the substrate are different. Thereby, when forming the exhaust-gas extension path continuous with the exhaust-gas flow path of a base material, a welding operation can be performed, for example, avoiding an obstruction.

  Thus, in the exhaust system component manufacturing method according to the fifth aspect, the exhaust gas extension path can be formed with a simple structure.

  An exhaust system component manufacturing method according to a sixth aspect of the present invention is the exhaust system component manufacturing method according to the fifth aspect, wherein in the base material preparation step, one end of the first member on the polymerized surface is overlapped. The base material in which the portion to be formed is recessed by the thickness of the first member with respect to the portion where the second member is overlapped is prepared, and the second joining step is performed after the first joining step. In the second joining step, both ends in the circumferential direction of the second member are superimposed on both ends in the circumferential direction of the first member, and in the third joining step, both ends in the circumferential direction of the second member. Are joined to the outer peripheral surface of the first member by welding.

  In the exhaust system component manufacturing method according to claim 6, after the base material preparation step, a first joining step is first performed, and one end portion of the first member superimposed on the polymerized surface of the base material is welded to the stepped portion. Is done. Next, a second bonding step is performed, and one end of the second member is overlapped with the polymerized surface, and both ends in the circumferential direction of the second member are overlapped with both ends of the first member, One end of the second member is welded to the outer peripheral surface of the base material. Then, a 3rd process is performed and the both ends of the circumferential direction of a 2nd member are welded to the outer peripheral surface of a 1st member. In this third step, welding (for example, fillet welding) can be performed in a state where the second member and the first member are overlapped, so that excessive dimensional accuracy is not required for each member, and welding is also performed. Easy to work and easy to ensure welding quality.

  As described above, the exhaust system component and the exhaust system component manufacturing method according to the present invention have an excellent effect that the exhaust gas extension path can be formed with a simple structure.

  A muffler 11 to which a muff linet member 10 as an exhaust system component according to an embodiment of the present invention is applied will be described with reference to FIGS. First, the overall configuration of the muffler 11 will be described, and then the detailed configuration of the mufflerlet member 10 will be described. For convenience of explanation, directions indicated by arrows FR, UP, and W, which are appropriately shown in the drawings, are a forward direction (traveling direction), an upward direction, and a vehicle width direction of the automobile on which the muffler 11 is mounted, respectively. .

(Overall structure of muffler)
FIG. 9 shows the muffler 11 in a perspective view. As shown in this figure, the muffler 11 includes a muffler body 12 having a hollow structure. The muffler body 12 is configured by joining an upper shell 14 and a lower shell 16. As shown in FIG. 7 which is a plan view with the upper shell 14 removed, and FIG. 8 which is a cross-sectional view taken along line 3-3 in FIG. 7, the muffler body 12 has a substantially longitudinal shape in the vehicle width direction in plan view. It is formed in a rectangular shape, and in this embodiment, it is formed in a flat shape whose vertical dimension is smaller than the longitudinal dimension. In this embodiment, the muffler main body 12 is configured to have a substantially elliptical shape in a side sectional view except for a central portion in the longitudinal direction (final expansion chamber 30 described later) (not shown).

  As shown in FIGS. 6 and 9, which are cross-sectional views taken along line 1-1 of FIG. 7, the upper shell 14 is formed to be elongated in the vehicle width direction and open downward. Except at both ends, it has a substantially constant shape (arc shape opening downward) in a cross-sectional view orthogonal to the longitudinal direction. The lower shell 16 is formed substantially symmetrically with the upper shell 14 except for the central portion in the longitudinal (vehicle width) direction. As shown in FIG. 8, a bulging portion 18 that protrudes downward in the vertical direction of the vehicle body is formed at the center portion of the lower shell 16 in the vehicle width direction. The bulging portion 18 is a part of a sphere. It is formed in the shape of an upward-facing concave bowl.

  7 and 8, the interior of the muffler main body 12 is divided into five parts in the vehicle width direction by two pairs of partition plates 20 and 22 arranged substantially symmetrically with respect to the center part in the vehicle width direction. ing. The pair of partition plates 20 are each formed in a bowl shape that is continuous with the bulging portion 18 and forms a spherical shape. In the muffler 11, the upper shell 14, the lower shell 16 including the bulging portion 18, and the pair of partition plates 20 form a spherical portion 24 having a substantially spherical shape at the center in the vehicle width direction. Yes. Further, a flat plate-like separator 26 is provided in the muffler 11 to connect the pair of partition plates 20 to partition the space in the spherical portion 24 in the vehicle body front-rear direction.

  A space located on the front side in the longitudinal direction of the vehicle body with respect to the separator 26 in the space in the spherical portion 24 is a first expansion chamber 28 of the muffler 11. A space located on the rear side in the direction is a final expansion chamber 30 of the muffler 11. Accordingly, as shown in FIGS. 6 to 8, the final expansion chamber 30 of the muffler 11 includes an upper wall 30 </ b> A mainly constituted by the upper shell 14, a lower wall 30 </ b> B mainly constituted by the bulging portion 18, mainly a pair of pairs. A side wall 30C formed by the partition plate 20, and a rear wall 30D formed mainly by the upper shell 14 and the lower shell 16 are formed in a continuous spherical shape.

  As shown in FIGS. 7 and 8, the pair of partition plates 22 are each formed in a flat plate shape, and are disposed in the vicinity of the end in the vehicle width direction in the muffler body 12. Spaces between the pair of partition plates 20 and the partition plate 22 are respectively formed as second expansion chambers 32, and the first is defined by a plurality of small holes 20 </ b> A (see FIG. 6) formed in front portions of the pair of partition plates 20. The expansion chamber 28 is in communication.

  On the other hand, as shown in FIGS. 7 and 8, the space formed on the outer side in the vehicle width direction of the pair of partition plates 22 is a third expansion chamber 34, and the communication holes formed in the pair of partition plates 22. The second expansion chamber 32 communicates with 22A. Each third expansion chamber 34 communicates with the final expansion chamber 30 by a communication pipe 36 that penetrates the partition plate 20 and the partition plate 22, respectively.

  As shown in FIGS. 6 to 8, the muffler main body 12 described above is connected to a muff linelet member 10 for introducing exhaust gas therein. As will be described in detail later, a part of the muff linelet member 10 is inserted into the muffler main body 12 from the front side in the longitudinal direction of the vehicle body, and a gas introduction part 40 communicated with the exhaust manifold of the engine through an exhaust pipe (not shown). , A low-speed gas flow path forming part 42 communicating with the gas introducing part 40 and opening in the first expansion chamber 28, a high-speed gas flow path forming part 44 communicating with the gas introducing part 40, and an upstream end for high-speed use The bypass passage forming portion 45 which is connected to the gas passage forming portion 44 and whose intermediate portion penetrates the first extension chamber 28 opens at the downstream end in the final extension chamber 30 and the flow path of the exhaust gas are slow. A valve device 46 for switching to the gas flow path forming part 42 or the high-speed gas flow path forming part 44 is configured as a main part.

  In this embodiment, the muffler 11 is applied to an exhaust system of a V-type multi-cylinder engine, and a pair of exhaust pipes connected independently to the left and right banks of the engine are connected. In addition, the gas introduction part 40 has two exhaust pipe connection parts 40A. In the muffle line member 10, the downstream portion of the gas introduction portion 40 in the exhaust gas flow direction, the high-speed gas flow passage forming portion 44, and the bypass flow passage forming portion 45 are continuously arranged in a substantially straight line along the longitudinal direction of the vehicle body. In addition, a valve device 46 is disposed in the high-speed gas flow path forming portion 44 constituting the linear portion.

  The valve device 46 takes an open posture for opening the communication passage (the high-speed gas flow passage formation portion 44 itself) between the gas introduction portion 40 and the high-speed gas flow passage formation portion 44 and a closing posture for closing the communication passage. When the engine speed exceeds a predetermined speed (first threshold) by a driving device (not shown), the closed position is switched to the open position, and the engine speed is separately set to a predetermined speed. When it falls below the number (second threshold), the open posture is switched to the closed posture. The second threshold value may be the same as or different from the first threshold value.

  The low-speed gas flow path forming part 42 is branched from the upstream side in the exhaust gas flow direction (front side in the longitudinal direction of the vehicle body) with respect to the installation part of the valve device 46 in the gas introduction part 40. Accordingly, the low-speed gas flow path forming unit 42 is configured to be able to introduce the exhaust gas into the first expansion chamber 28 of the muffler body 12 in a state where the valve device 46 is in the closed posture. In this embodiment, the low-speed gas flow path forming part 42 is provided adjacent to the lower side in the vehicle body vertical direction with respect to the high-speed gas flow path forming part 44 (without a gap). Thereby, the muff linet member 10 is sandwiched between the joint portions of the upper shell 14 and the lower shell 16 in an airtight state, and is fixedly held to the muffler main body 12.

  As described above, in the muffler 11, when the valve device 46 is in the closed position, as shown by a thin solid line or a broken line arrow A in FIGS. The exhaust gas introduced from the portion 40 flows from the low-speed exhaust gas flow passage 42A in the low-speed gas flow passage formation portion 42 to the first expansion chamber 28, the partition plate 20 (the plurality of small holes 20A), and the second expansion chamber 32. The partition plate 22 (communication hole 22A), the third expansion chamber 34, and the communication pipe 36 are guided to the final expansion chamber 30. This exhaust gas flow path is referred to as an exhaust gas path A.

  On the other hand, in the state in which the valve device 46 is in the open position, the valve device 46 is introduced from the gas introduction part 40 of the muff linet member 10 as shown by a thick solid line or broken line arrow B in FIGS. 10 (A) and 10 (B). The exhaust gas is guided to the final expansion chamber 30 through the high-speed exhaust gas flow path 44A in the high-speed gas flow path forming section 44 and the bypass flow path 45A in the bypass flow path forming section 45. This exhaust gas flow path is referred to as an exhaust gas path B. When the valve device 46 is in the open position, the flow resistance (pressure loss) of the exhaust gas path A is sufficiently larger than the flow resistance of the exhaust gas path B. It can be considered that the gas flows through the gas path A.

  The muffler 11 includes an exhaust gas discharge unit 48 for discharging exhaust gas from the final expansion chamber 30. The exhaust gas discharge portion 48 is configured to have a plurality of outlet pipes (exit pipes) each having one end opened in the final expansion chamber 30 and the other end serving as a rear end in the vehicle body front-rear direction being an open end to the atmosphere. The exhaust noise is adjusted. This will be specifically described below.

  The exhaust gas discharge portion 48 includes a pair of outlet pipes 50 as first cylindrical members each having a cylindrical shape, and a single outlet pipe 52 as a second cylindrical member having a cylindrical shape longer than the outlet pipe 50. It is comprised including. In this embodiment, as shown in FIG. 6, the length L2 of the outlet pipe 52 is at least twice as long as the length L1 of the outlet pipe 50 (L2 ≧ 2 × L1). The pair of outlet pipes 50 are sandwiched between the joint portions of the upper shell 14 and the lower shell 16 in an airtight state (through the rear wall 30D), and the longitudinal direction ( The vehicle width is fixedly held at the center in the direction away from each other.

  In the outlet pipe 52, the components of the lower wall 30B and the rear wall 30D in the lower shell 16 are arranged so that the position of the atmosphere open end 52A in the vehicle longitudinal direction substantially coincides with the position of the atmosphere open end 50A of each outlet pipe 50. It penetrates in an airtight state. The outlet pipe 52 is supported by the bulging portion 18 via a bracket 54 at an axial end portion 52 </ b> B located in the final expansion chamber 30. As described above, the outlet pipe 52 is disposed in the vehicle body vertical direction lower side of the pair of outlet pipes 50 at the longitudinal center portion of the muffler main body 12, and, as shown in FIG. It has a substantially triangular shape.

  Further, the exhaust gas discharge part 48 has a sound absorbing structure 56 provided in the outlet pipe 52. The sound absorbing structure 56 is configured by winding glass wool 58 as a sound absorbing member around the outer periphery of the outlet pipe 52. The glass wool 58 is held on the outer periphery of the outlet pipe 52 by a cover member 60 fixed to the outer periphery of the outlet pipe 52. In this embodiment, the bracket 54 is provided only in a portion of the outlet pipe 52 located in the final expansion chamber 30.

(Detailed configuration of mufflinet member)
FIG. 1 shows a side view of the muff linet member 10. 2 is a cross-sectional view taken along line 2-2 of FIG. 1, and FIG. 3 shows an essential part of the muff linet member 10 in an exploded perspective view. 4 is a sectional view taken along line 4-4 in FIG. 2, and FIG. 5 is a sectional view taken along line 5-5 in FIG. As shown in FIGS. 1 and 3, the muff linet member 10 includes a base portion 62 as a base material in the present invention. As shown in FIG. 5, the base portion 62 includes a gas introduction portion 40 (a pair of exhaust pipe connection portions 40 </ b> A), a low-speed gas flow path formation portion 42 that forms an opening end 42 </ b> B as a second opening portion, a first portion. A high-speed gas flow path forming portion 44 that forms an opening end portion 44B as an opening portion is integrally formed. In this embodiment, the base part 62 is comprised by casting of metal materials, such as titanium or a titanium alloy, for example, and the thickness of each part is about 2 mm.

  As shown in FIGS. 1 to 4, in the mufflinet member 10, the bypass flow path forming portion 45 is closed by joining the upper half 64 as the second member and the lower half 66 as the first member. The bypass channel 45A having a cross-sectional structure is formed (a so-called monaca structure). As shown in FIGS. 2 and 3, in this embodiment, the high-speed gas flow path forming portion 44 corresponds to the exhaust pipe connecting portion 40A for the left and right banks, and the base portion 62 has a pair of left and right high-speed gases. A flow passage forming portion 44 is formed, and a single closed passage is formed in the bypass flow passage forming portion 45 so that the high speed exhaust gas flow passage 44A in the pair of high speed gas flow passage forming portions 44 merges. A bypass channel 45A having a cross-sectional structure is formed.

  Therefore, as shown in FIG. 2, in this embodiment, the bypass channel 45 </ b> A has a shape (gourd shape) in which two circular shapes are combined. More specifically, as shown in FIG. 3, the upper half 64 forms a substantially wave shape that opens downward to constitute the upper half of the bypass flow path forming portion 45, and the lower half 66 faces upward. The lower half of the bypass flow path forming portion 45 is formed in a substantially wave shape that is open to each other, and both end portions in the circumferential direction (end portions located at end portions in the vehicle width direction) are joined to each other. Thus, a bypass flow path forming portion 45 having a closed cross-sectional structure is formed. The upper half 64 and the lower half 66 are formed, for example, by pressing (drawing) a metal material such as titanium or a titanium alloy, and each part has a thickness of about 1 mm to 1.5 mm.

  The upper half 64 and the lower half 66 are joined to the opening end portion 44B of the high-speed gas flow path forming portion 44 in the base portion 62 by welding. This will be specifically described below.

  As shown in FIGS. 3 and 4, the upper half of the outer peripheral surface of the predetermined range on the upstream side in the exhaust gas flow direction from the opening end 44B of the high-speed gas flow path forming portion 44, that is, the opening end 44C as the large first opening end. Is the upper polymerized portion 68. The upper polymerized portion 68 is smoothly continuous with the outer peripheral surface of the portion constituting the high-speed gas flow path forming portion 44 in the base portion 62, and has a substantially wave shape corresponding to the lower surface of the upper half 64 in the rear view. Yes.

  In the upper polymerized portion 68, an upstream end portion (front end portion in the vehicle longitudinal direction) of the upper half 64 in the exhaust gas flow direction is overlapped from above. In this state, as shown in FIG. 4, the upper half 64 and the base portion 62 are formed such that the front end face 64 </ b> A of the upper half 64 and the outer peripheral surface of the base portion 62 (high-speed gas flow path forming portion 44) are welded portions Wu. It is joined by. Wu is formed by fillet welding over the entire length of the upper polymerized portion 68.

  As shown in FIGS. 3 and 4, the lower half of the outer peripheral surface of the opening end 44 </ b> B of the high-speed gas flow path forming portion 44, that is, the opening as the second opening constituting the low-speed gas flow path forming portion 42. The portion on the end 42B side is a lower polymerized portion 70. The lower polymerized portion 70 is recessed by the thickness of the lower half 66 with respect to the outer peripheral surface of the portion constituting the high-speed gas flow path forming portion 44 in the base portion 62, and the upper polymerized portion forming both ends in the circumferential direction. A stepped portion 72 is formed at each boundary portion with the portion 68. Therefore, the height of the stepped portion 72 corresponds to the thickness of the lower half 66. Further, a stepped portion 74 facing the downstream side in the exhaust gas flow direction is formed at the upstream end of the lower polymerized portion 70 in the exhaust gas flow direction over the entire length of the lower polymerized portion 70. Yes. As shown in FIGS. 3 and 4, the stepped portion 74 has a height relative to the lower polymerized portion 70 (the bottom surface of the recess) by partially increasing the thickness of the high-speed gas flow path forming portion 44. Is larger than the thickness of the lower half 66. In this embodiment, the height of the stepped portion 74 is about 1.5 to 2 times the thickness of the lower half 66.

  The lower polymerized portion 70 and the stepped portion 74 described above have a substantially wave shape corresponding to the upper surface of the lower half 66 in the rear view. The lower polymerized portion 70 has an upstream end portion in the exhaust gas flow direction (front end portion in the front-rear direction of the vehicle body) of the lower half 66 in which a front end surface 66A that is an upstream end in the exhaust gas flow direction is abutted against the stepped portion 74. It is designed to be stacked from below. In this state, as shown in FIG. 4, the lower half 66 and the base portion 62 are formed by connecting the front end portion 66B of the lower half 66 and the stepped portion 74 of the base portion 62 (high-speed gas flow path forming portion 44). Joined by Wl. The welded portion Wl is formed by fillet welding over the entire length of the stepped portion 74 (lower polymerized portion 70).

  As described above, the lower half 66 superimposed on the lower polymerized portion 70 that is a recess with respect to the outer peripheral surface of the high-speed gas flow path forming portion 44 is formed smaller than the upper half 64 by the thickness. As shown in FIG. 2, both end portions 64 </ b> B in the circumferential direction of the base portion 62 in the upper half 64 are superimposed on both end portions 66 </ b> C in the circumferential direction of the base portion 62 in the lower half 66. The end surface 64 </ b> C in the circumferential direction of the upper half 64 is joined to the outer peripheral surface of the lower half 66 by a welded portion Ws. The welded portion Ws is formed by fillet welding over the entire length of the upper half 64 and the lower half 66 in the exhaust gas flow direction.

  Next, the operation of the embodiment will be described.

  In the muffler 11 to which the mufflinet member 10 having the above-described configuration is applied, for example, when the engine speed is lower than a predetermined speed, the valve device 46 is closed, and the gas introduction unit 40 of the mufflinet member 10 The introduced exhaust gas is introduced into the first expansion chamber 28 of the muffler main body 12 via the low-speed exhaust gas flow path 42A of the low-speed gas flow path forming portion 42, and further the second expansion chamber 32 and the third expansion. The sound is silenced through the chamber 34, the communication pipe 36, and the final expansion chamber 30, and is released to the atmosphere from the pair of outlet pipes 50 and outlet pipes 52 that constitute the exhaust gas discharge unit 48.

  On the other hand, for example, when the engine rotational speed exceeds a predetermined rotational speed, the valve device 46 is in an open posture, and the exhaust gas introduced from the gas introducing portion 40 of the muff linelet member 10 is sent to the high-speed gas flow path forming portion. A pair of high-speed exhaust gas passages 44 A and a bypass passage 45 A of the bypass passage forming portion 45 that are linearly passed through the final expansion chamber 30 of the muffler body 12 and constitute an exhaust gas discharge portion 48. The outlet pipe 50 and the outlet pipe 52 are released to the atmosphere. In this case, the exhaust gas is discharged through a short path, so that the back pressure (exhaust resistance) is small and contributes to the improvement of the engine output.

  In manufacturing the muff linet member 10 described above, first, the upper polymerized portion 68, the lower polymerized portion 70 (stepped portion 72), and the stepped portion 74 are the open ends of the high-speed gas flow path forming portion 44. The base portion 62 formed on the portion 44B is formed by casting (base material preparation step). Further, the substantially wave-shaped upper half 64 and lower half 66 are formed by press molding.

  Next, the lower half 66 is overlapped with the lower polymerized portion 70 from the lower side, and the front end 66B of the lower half 66 is abutted against the stepped portion 74, and the outer periphery of the stepped portion 74 and the lower half 66 in the vicinity of the front end 66B. The surface is welded, and the lower half 66 is joined to the base portion 62 at the welded portion Wl (first joining step). Further, the upper half 64 is superposed on the upper polymerized portion 68 from above, and the upper half 64 is positioned with respect to the lower half 66 in the exhaust gas flow direction. From this state, the front end face 64A and the outer peripheral surface of the high-speed gas flow path forming portion 44 are welded, and the upper half 64 is joined to the base portion 62 at the welded portion Wu (second joining step).

  In this state, both end portions 64B in the circumferential direction of the base portion 62 are overlapped with both end portions 66C in the circumferential direction of the base portion 62 from the outside. Then, the circumferential end surface 64C of the upper half 64 is welded to the outer circumferential surfaces of both circumferential end portions 66C of the lower half 66, and the upper half 64 and the lower half 66 are joined at the welded portion Ws (third). Joining process). As described above, the bypass flow path 45A having the closed cross-sectional structure of the bypass flow path forming section 45 continuous with the two high speed gas flow path forming sections 44 is communicated with the two high speed exhaust gas flow paths 44A.

  Here, in the muff linelet member 10 and the manufacturing method of the muff linelet member 10, the bypass flow path forming portion 45 includes the upper half 64 and the lower half 66, and the upstream side in the exhaust gas flow direction in the upper half 64. Since the front end face 64A facing the base member 62 is welded and joined, and the front end part 66B of the lower half 66 is welded and joined to the stepped part 74 that abuts the front end face 66A. Welding workability during manufacturing is improved.

  Specifically, as shown in FIG. 1, when welding the upper half 64 to the base portion 62, the welding torch Tw can be inserted from the direction of approximately 45 ° upstream of the exhaust gas flow direction. At the time of welding to the base portion 62, the welding torch Tw can be inserted from a direction approximately 45 ° downstream of the exhaust gas flow direction. As a result, the bypass flow path forming portion 45 is formed against the base portion 62 in which the low speed gas flow path forming portion 42 is formed adjacent to the high speed gas flow path forming portion 44 to which the bypass flow path forming portion 45 is connected. Can be bonded reliably and with high quality. For this reason, compared with the structure which includes the bypass flow path formation part 45 and forms the base part 62 by casting, the mufflinet member 10 can be obtained at low cost.

  Further, in the muff linelet member 10 and the manufacturing method of the muff linelet member 10, both end portions 64 </ b> B in the circumferential direction of the base portion 62 are overlapped with both end portions 66 </ b> C in the circumferential direction of the base portion 62 in the circumferential direction of the upper half 64. In order to perform welding between the end face 64C and the outer peripheral surface of the lower half 66, for example, compared with a configuration in which the end face 64C in the circumferential direction of the upper half 64 and the end face in the circumferential direction of the lower half 66 are abutted to perform butt welding, The welding operation of the upper and lower halves 64 and 66 can be performed easily and with high quality.

  In the above-described embodiment, the example in which the lower polymerized portion 70 is formed as a concave portion with respect to the outer peripheral surface of the high-speed gas flow path forming portion 44 is shown, but the present invention is not limited to this. The lower polymerized portion 70 may be formed flush (smoothly and continuously) with the upper polymerized portion 68 by configuring 74 as a convex portion with respect to the high-speed gas flow path forming portion 44. You may form as a convex part with respect to the to-be-polymerized part 68. FIG. For example, in the former case, the upper half 64 and the lower half 66 may be configured to join the circumferential ends of each other by butt welding, and in the latter case, the upper half 64 and the lower half 66. It is only necessary to reverse the superposition with the above embodiment.

  In the above-described embodiment, the example in which the height of the stepped portion 74 is larger than the thickness of the lower half 66 (the height of the stepped portion 72) is shown, but the present invention is not limited to this. In addition, a structure in which a groove is formed between the front end face 66A and the stepped portion 74 and welding is performed, and the height of the stepped portion 74 may be equal to the thickness of the lower half 66.

  Furthermore, in the above-described embodiment, the example in which the exhaust system component of the present invention is applied to the mufflinet member 10 is shown. However, the present invention is not limited to this, for example, an engine exhaust manifold or an exhaust pipe branching portion. The exhaust system parts of the present invention may be applied to a muffler, a bypass portion of an exhaust heat recovery device, and the like.

It is a side view of the muff linet member concerning the embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line 2-2 in FIG. It is a disassembled perspective view which shows the principal part of the muff linet member which concerns on embodiment of this invention. FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. 2. FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. It is a figure which shows the muffler to which the muff linet member which concerns on embodiment of this invention was applied, Comprising: It is sectional drawing which follows the 1-1 line | wire of FIG. It is a top view which shows the internal structure of the muffler to which the muff linet member which concerns on embodiment of this invention was applied. It is sectional drawing which follows the 3-3 line of FIG. It is a perspective view of the muffler to which the muff linet member concerning the embodiment of the present invention was applied. It is a figure for demonstrating the exhaust gas flow path | route of the muffler to which the muff linelet member which concerns on embodiment of this invention was applied, Comprising: (A) is a top view, (B) is a sectional side view.

Explanation of symbols

10 Mufflinet member (exhaust system parts, muffler inlet member)
11 Muffler 28 First expansion chamber 30 Final expansion chamber 42B Open end (second opening)
44A High-speed exhaust gas flow path (exhaust gas flow path)
44B Opening end (first opening)
45A bypass passage (exhaust gas extension passage)
62 Base part (base material)
64 Upper half (second member)
66 Lower half (first member)
68 Upper polymerized part (polymerized part)
70 Lower polymerized part (polymerized part)
74 steps

Claims (6)

The polymerized portion formed on the outer periphery of the opening end portion of the exhaust gas passage formed inside, and the polymerized portion side toward a part of the circumferential direction at the end portion in the exhaust gas flow direction with respect to the polymerized portion A base material having a step portion formed by:
One end portion in the exhaust gas flow direction is overlapped with a circumferential range in which the step portion in the polymerized portion is formed and is abutted against the step portion and joined to the step portion; ,
One end portion in the exhaust gas flow direction is overlapped with a range where the stepped portion in the circumferential direction in the polymerized portion of the base material is not formed and joined to the outer peripheral surface of the base material, and both ends in the circumferential direction A second member that is joined to both ends in the circumferential direction of the first member and forms an exhaust gas extension passage having a closed cross-sectional structure that is continuous with the gas flow passage with the first member;
Exhaust system parts with The portion where the first member in the polymerized portion is superimposed is recessed by the thickness of the first member with respect to the portion where the second member in the polymerized portion is superimposed,
The exhaust system component according to claim 1, wherein both end portions in the circumferential direction of the second member are overlapped and joined to both end portions in the circumferential direction of the first member.   The base has a first opening that is an opening of the exhaust gas flow path, and a second opening that opens adjacent to the first opening, and the stepped portion is the first opening. The exhaust system component according to claim 1, wherein the exhaust system component is formed on the second opening side of the portion.   The exhaust gas extension path is a muffler inlet member that opens through the first expansion chamber of the muffler and opens into the final expansion chamber, and the second opening portion opens into the first expansion chamber. Exhaust system parts. The polymerized portion formed on the outer periphery of the opening end portion of the exhaust gas passage formed inside, and the polymerized portion side toward a part of the circumferential direction at the end portion in the exhaust gas flow direction with respect to the polymerized portion A base material preparation step of preparing a base material having a stepped portion formed by:
A first joining step of abutting one end portion of the first member in the exhaust gas flow direction on the stepped portion of the base material and overlapping the polymerized surface, and welding the one end portion of the first member to the stepped portion;
One end of the second member in the exhaust gas flow direction is overlapped with the first member on the polymerized surface of the base material in a range where the first member is not overlapped, and one end of the second member is welded to the outer peripheral surface of the base material. A second joining step,
A third joining step of welding both circumferential ends of the first member and circumferential ends of the second member;
A method for manufacturing exhaust system parts including: In the base material preparation step, the base where the one end portion of the first member on the surface to be polymerized is recessed by the thickness of the first member with respect to the portion where the second member is overlapped. The material is prepared,
The second joining step is performed after the first joining step, and in the second joining step, both ends in the circumferential direction of the second member are overlapped with both ends in the circumferential direction of the first member,
The exhaust system component manufacturing method according to claim 5, wherein in the third joining step, both ends in the circumferential direction of the second member are joined to the outer peripheral surface of the first member by welding.

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