JP2005036724A - Exhaust manifold - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust manifold of a structure capable of preventing welding spatter from entering therein. <P>SOLUTION: This exhaust manifold comprises a first shell half 12a and a second shell half 12b in which shell parts (manifolds) hold one end sides of branch tubes 11 arranged parallel with each other at specified intervals by these edge parts 12c and 12d. The edge part 12c of the first shell half 12a is shifted in the extending direction of the branch tube 11 relative to the edge part 12d of the second shell half 12b. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an exhaust manifold for discharging engine exhaust gas to the outside.

Conventionally, an exhaust manifold comprising a plurality of branch pipes and a collecting pipe that is joined to the branch pipes and collects exhaust gas flowing in the branch pipes, the half of the branch pipe part and the half of the collecting pipe part, There has been known an exhaust manifold in which a unitary body is welded while facing each other (see, for example, Patent Document 1). According to such an exhaust manifold, by welding the halves together, it is possible to easily form a pipe line through which the exhaust gas flows, so that the manufacturing process of the exhaust manifold can be simplified.
Japanese Patent Laid-Open No. 9-60519 (paragraphs 0012 to 0014 and FIGS. 1 and 3)

  However, in this exhaust manifold, there is a difference in thermal strain between the halves of the branch pipes when the engine is driven. Therefore, the path of the branch pipe connecting the exhaust port of the engine to the collecting pipe is complicated with a curve. It was difficult to set a simple route. In order to solve such a problem, for example, FIG. 6A and FIG. 6B (FIG. 6B is a cross-sectional view taken along line XX in FIG. 6A). As shown, the pipes 21 are made of ordinary pipes, that is, pipes that are not joined to each other, and halves 22a, 22a of the collecting pipe 22 (hereinafter referred to as the ends of the branch pipes 21). An exhaust manifold 20 in which the “half bodies 22a and 22a” are joined to each other is conceivable. According to such an exhaust manifold 20, since a normal pipe is used for the branch pipe 21, the path of the branch pipe 21 can be freely set.

  By the way, in manufacturing the exhaust manifold 20 having such a structure, the joint between the half bodies 22a and 22a sandwiching the branch pipe 21 and the joint between the branch pipe 21 and the half bodies 22a and 22a are welded. At this time, as shown in FIG. 6C, the welding torch T is directed from the upper side of the collecting pipe 22 (above the paper surface of FIG. 6C) to the above-mentioned joint.

  On the other hand, around the branch pipe 21 sandwiched between the half bodies 22a and 22a, as shown in FIGS. 6 (b) and 6 (c), a pair of half bodies 22a and 22a and the branch pipe 21 are connected. A defined air gap 24 is formed. The gap 24 communicates with the inside of the collecting pipe 22 along the peripheral wall of the branch pipe 21.

  When welding is performed on the seam with the welding torch T disposed from above the collecting pipe 22 toward the seam, welding spatter and molten components (hereinafter referred to as “weld spatter” and the like) pass through the gap 24. It enters the collecting pipe 22 (in the exhaust manifold 20).

  On the other hand, a catalyst carrier unit for treating air pollutants such as nitrogen oxides in exhaust gas is attached to recent exhaust manifolds. In this exhaust manifold, since metal oxides such as the above-described welding spatter adversely affect the catalyst carrier unit, it is necessary to surely prevent the welding spatter from entering the exhaust manifold.

  Accordingly, an object of the present invention is to provide an exhaust manifold having a structure capable of preventing the entry of welding spatter and the like into the inside thereof.

  When welding the joints between the halves of the collecting pipe and the like, the inventor determines that the scattering direction of welding spatter and the like matches the direction in which the gap extends, that is, the direction in which the branch pipe extends. Based on the knowledge that welding spatter or the like enters, it has been found that by changing the direction of the welding torch to a specific direction, entry of welding spatter or the like into the exhaust manifold can be avoided. .

  That is, the invention according to claim 1 for solving the above-described problem is an exhaust manifold including a plurality of branch pipes and a collecting pipe that is joined to the branch pipes and collects exhaust gas flowing in the branch pipes. The collecting pipe is composed of a first half and a second half sandwiching one end side of the branch pipes arranged side by side at a predetermined interval with their edges, the first half and the One of the edge portions of the second half is shifted in a direction in which the branch pipe extends with respect to the other edge portion.

  According to such a configuration of the exhaust manifold, when the joint of the first half and the second half is welded, one of the edges of the first half and the second half is Since the branch pipe is displaced in the extending direction with respect to the edge of the first and second ends, the front end of the welding torch faces the surface of the first half and the second half that are exposed to be displaced. Half seams can be welded. That is, according to this configuration, a direction that does not coincide with the direction of the gap extending into the collecting pipe along the branch pipe, for example, a direction that intersects the joint surface between the edges of the first and second halves. The position of the welding torch can be controlled so that welding spatter and the like are scattered.

  The manufacturing method of such an exhaust manifold includes the steps of preparing the first half and the second half, and a plurality of the branch pipes whose edges are shifted from each other when combined with each other; Combining the first and second halves so that one end of the branch pipe disposed at a predetermined interval is sandwiched between the edges of the first and second halves; And the step of welding the edges of the first and second halves by setting the direction of the welding torch in a direction intersecting the joint surface between the edges.

  Further, in this exhaust manifold manufacturing method, when the edges are welded to each other, the welding torch is inclined at a predetermined angle toward the first and second half sides or perpendicular to the joint surface. It is preferable to maintain the posture.

  In the exhaust manifold manufacturing method, the predetermined angle is more preferably greater than 0 ° and not greater than 10 °.

  According to such an exhaust manifold manufacturing method, since the position of the welding torch is set so that welding spatter or the like scatters in the direction intersecting the joint surfaces of the edges of the first and second halves, It is possible to prevent welding spatter and the like from entering the collecting pipe composed of the first and second halves through the gap.

  Further, by adjusting the angle of the welding torch as described above, the entry of welding spatter and the like into the collecting pipe can be avoided more reliably.

  Further, in the above-described exhaust manifold manufacturing method, the step of welding the edges is a first welding step of welding a gap portion defined by the first and second halves and the branch pipe, and the first And a second welding step of welding the portions where the first and second halves contact each other, and after the step of welding the edges, the branch pipe, the first half body, the branch pipe, and the It is preferable that a third welding process for welding the second half is further provided, and the first welding process is configured to be performed prior to the second and third welding processes.

  According to such an exhaust manifold manufacturing method, since the gap is welded and closed by the first welding process performed first, in the second and third welding processes performed subsequent to the first welding process. Further, welding spatter or the like does not enter the collecting pipe through the gap. Therefore, according to this exhaust manifold manufacturing method, it is possible to more reliably prevent welding spatter and the like from entering the collecting pipe.

  Moreover, according to such an exhaust manifold manufacturing method, the edges of the first and second halves are welded throughout the first to third welding steps. That is, in this exhaust manifold manufacturing method, the above-described gap portion, the portion where the first and second halves contact each other, and the periphery of the branch pipe are welded in this order. Therefore, according to this exhaust manifold manufacturing method, the entire edge portion is compared with the case where welding is continuously performed from one end of the edge portion of the first and second halves toward the other end. Therefore, it is possible to suppress the occurrence of welding distortion.

  In the exhaust manifold of the present invention, the position of the welding torch can be controlled so that the welding spatter and the like are scattered in a direction that does not coincide with the direction of the gap extending along the branch pipe into the collecting pipe. It is possible to prevent entry into the exhaust manifold.

  Next, an embodiment of an exhaust manifold according to the present invention will be described with reference to the drawings as appropriate. In the drawings to be referred to, FIG. 1 is a perspective view of an exhaust manifold according to the present embodiment, FIG. 2 is an exploded perspective view of the exhaust manifold of FIG. 1, and FIG. 3 is a portion shown in a circle 3 in FIG. It is an enlarged view.

As shown in FIG. 1, the exhaust manifold M is used for an in-line four-cylinder engine E, and includes four branch pipes 11 connected in communication with the exhaust ports P of the cylinder head H. In addition to being connected to these branch pipes 11, a shell portion 12 having an internal space in which exhaust gas flowing from each branch pipe 11 gathers is provided. The shell portion 12 is formed with a discharge port 13 for discharging the collected exhaust gas to the outside of the shell portion 12. For example, a catalyst carrier unit 14 carrying a NO _x purification catalyst such as a platinum-based catalyst or a palladium-based catalyst is attached to the discharge port 13. That is, the exhaust gas discharged from the engine E flows through the exhaust manifold M constituted by the branch pipe 11 and the shell portion 12, and then passes through the catalyst carrier unit 14, a muffler, an exhaust pipe (not shown), and the like in the atmosphere. To be released. The shell portion 12 corresponds to a “collecting pipe” in the claims.

  The branch pipe 11 is integrated with one flange 11a on the upstream side of the flowing exhaust gas. The flanges 11 a are fixed to the cylinder head H with bolts B, so that the branch pipes 11 communicate with the exhaust ports P of the cylinder head H. The downstream sides of these branch pipes 11 are connected to the shell portion 12 so as to communicate with the shell portion 12 described below.

  As shown in FIG. 2, the shell portion 12 is composed of a first shell half 12a and a second shell half 12b. These first and second shell halves 12a and 12b are made of curved plate materials that are concave inward so that the internal space described above is formed when they are combined and joined to face each other. Yes. The first shell half 12a corresponds to the “first half” in the claims, and the second shell half 12b corresponds to the “second half” in the claims. .

  The discharge port 13 (see FIG. 1) of the shell portion 12 is formed so as to straddle the first shell half body 12a and the second shell half body 12b. That is, the circular discharge port 13 is formed by combining the semicircular rim portion 13a formed in the first shell half body 12a and the semicircular rim portion 13b formed in the second shell half body 12b. ing.

  Further, the shell portion 12 has four branch pipe insertion holes 15 (see FIG. 1) for receiving and joining the downstream ends of the branch pipes 11 in the internal space thereof. It is formed at a predetermined interval in the direction along the edges 12c and 12d of the bodies 12a and 12b. These branch pipe insertion holes 15 have substantially the same diameter as the outer diameter of the branch pipe 11, and are formed so as to straddle the first shell half body 12a and the second shell half body 12b. Each branch pipe 11 is joined to the shell portion 12 at the opening of the branch pipe insertion hole 15. Further, the edge portions 12c and 12d of the first and second shell halves 12a and 12b are joined to each other between the branch pipe insertion holes 15 formed at a predetermined interval.

  In addition, a joining edge F for joining the first and second shell halves 12a and 12b is formed on each side edge of the first and second shell halves 12a and 12b.

  And as shown in FIG. 3, the 1st and 2nd shell half bodies 12a arrange | positioned so that the downstream edge part of each branch pipe 11 may be inserted | pinched in the said branch pipe insertion hole 15 (refer FIG. 1), 12b is joined so that the edge 12c of the first shell half 12a and the edge 12d of the second shell half 12b are displaced, and the edge 12c of the first shell half 12a Retreats with a width W toward the downstream side. The width W is not particularly limited, but is preferably set to a length approximately equal to the thickness of the first and second shell halves 12a and 12b.

  Next, a method for manufacturing the exhaust manifold according to the present embodiment will be described with reference to the drawings as appropriate. In the drawings to be referred to, FIGS. 4 (a), 4 (b) and 5 are schematic views for explaining the manufacturing process of the exhaust manifold according to the present embodiment. FIG. 4B is a cross-sectional view taken along line YY in FIG.

  First, a branch pipe 11 having a predetermined shape as shown in FIG. 2 and first and second shell halves 12a and 12b are prepared. The branch pipe 11 may be manufactured by, for example, a pipe forming machine, press working, forging, or the like, and the first and second shell halves 12a, 12b may be manufactured by, for example, pressing or forging.

  Next, as shown in FIGS. 4A and 4B, on the predetermined support base S, the second shell half 12b is on the lower side, and the first shell half 12a is on the upper side. These are combined to face each other, and the downstream end of each branch pipe 11 is fitted into the branch pipe insertion hole 15 (see FIG. 4B). At this time, the edge portion 12c of the first shell half body 12a recedes with a width W toward the downstream side of the branch pipe 11 as described above. A space 24 defined by the branch pipe 11 and the first and second shell halves 12a and 12b is formed around the branch pipe 11.

  Next, the gap 24 and the portions where the edges 12c and 12d of the first and second shell halves 12a and 12b are in contact with each other are welded in this order. At this time, the welding torch T is arranged such that its tip faces the exposed upper surface of the edge 12d of the second shell half 12b, and the edge 12c of the first shell half 12a and the second shell half 12b. The posture is controlled so that the direction of the welding torch T coincides with the direction intersecting the joint surface with the edge 12d. More specifically, as shown in FIG. 4B, the welding torch is maintained in a posture that is perpendicular to the joint surface between the edge 12c and the edge 12d, or the first It is preferable that the second shell half body 12a, 12b is inclined at an angle of about 0 ° to 10 °.

  When the edges 12c and 12d of the first and second shell halves 12a and 12b are welded with the welding torch T maintained in such a posture, the direction in which the welding spatter scatters is the edges 12c and 12d. It intersects the joint surface. That is, the direction in which the gap 24 extends does not match the direction in which the weld spatter is scattered. Therefore, entry of welding spatter or the like into the shell portion 12 through the gap 24 is avoided.

  Further, when the edges 12c and 12d of the first and second shell halves 12a and 12b are welded in this way, the gap 24 portion is closed by being welded first, so this welding step The welding spatter and the like scattered in the subsequent welding process will not enter the shell portion 12 from the gap 24. A welded portion WD is formed on the exposed upper surface of the edge portion 12d as shown in FIG.

  When the welding of the gap 24 and the portion where the edges 12c and 12d of the first and second shell halves 12a and 12b are in contact with each other is completed, the periphery of the branch pipe 11 is welded as shown in FIG.

  Thus, when the edge portions 12c and 12d of the shell halves 12a and 12b are welded, the above-described gap 24 portion, the portion where the edge portions 12c and 12d are in contact with each other, and the periphery of the branch pipe 11 are sequentially welded. Therefore, in this exhaust manifold manufacturing method, the entire edges 12c and 12d are well balanced compared to the case where welding is continuously performed from one end of the edges 12c and 12d toward the other end. Can be welded. Therefore, according to this exhaust manifold manufacturing method, the occurrence of welding distortion is suppressed.

  Then, after the joints of the first and second shell halves 12a and 12b at the joint edge F are welded, if the welded portion is polished as necessary, the manufacture of the exhaust manifold M according to the present embodiment. The process ends.

  In such an exhaust manifold M according to the present embodiment, the edge portion 12c of the first shell half body 12a that sandwiches and connects each branch pipe 11 is connected to the edge portion 12d of the second shell half body 12b. 11, when welding the seam of the first shell half body 12 a and the second shell half body 12 b, a welding torch is applied to the joint surface between the edge portions 12 c and 12 d. The welding torch T can be arranged in such a posture that the longitudinal directions of T intersect. That is, the attitude of the welding torch can be controlled so that welding spatters and the like are scattered in a direction that does not coincide with the direction of the gap 24 extending into the shell portion 12 along the branch pipe 11. Therefore, according to the exhaust manifold M having such a structure, it is possible to prevent welding spatter and the like from entering the inside.

  As shown in FIG. 6 (a), in the conventional exhaust manifold 20, the edges of the half bodies 22a, 22a of the collecting pipe 22 are aligned with each other. The collecting pipe 22 is arranged so as to face upward. That is, the collecting pipe 22 is arranged so that the extending direction of the gap 24 (see FIG. 6B) coincides with the vertical direction. When the welding torch is brought close to the joint of the collecting pipes 22 arranged in this way from above, the molten weld metal may flow down the gap 24 and enter the collecting pipe 22. On the other hand, in the exhaust manifold M according to the present embodiment, as described above, the first and second shell halves 12a and 12b can be arranged so that the extending direction of the gap 24 coincides with the horizontal direction. (See FIG. 4 (a) and FIG. 4 (b)). Therefore, in the exhaust manifold M according to the present embodiment, the molten weld metal does not flow down the gap 24 and enter the shell portion 12.

Although the exhaust manifold M of the present invention has been specifically described based on the embodiment, the present invention is not limited to this embodiment.
For example, in the present embodiment, the edge 12c of the first shell half 12a is retracted downstream of the branch pipe 11 with respect to the edge 12d of the second shell half 12b (see FIG. 3). The present invention is not limited to this, and the edge portion 12d of the second shell half body 12b is retracted toward the downstream side of the branch pipe 11 with respect to the edge portion 12c of the first shell half body 12a. You may do it.

  In the present embodiment, the ends of the connecting edges F formed on both side edges of the first shell half body 12a and the second shell half body 12b are aligned (FIGS. 2 and 4). a) see), the present invention is not limited to this, and the end of one connection edge F of the first shell half body 12a and the second shell half body 12b extends from the end of the other connection edge F. It may be an exhaust manifold formed so as to be displaced. According to such an exhaust manifold, when the connection edges F of the first shell half 12a and the second shell half 12b are welded to each other, the orientation of the welding torch T with respect to the joint surface of these connection edges F is The welding torch T can be arranged in a posture that intersects. That is, the attitude of the welding torch T when welding the connection edges F is made to coincide with the attitude of the welding torch T when welding the edge portions 12c and 12d of the first and second shell halves 12a and 12b. be able to. Therefore, according to this exhaust manifold, the welding of the edges 12c and 12d of the first and second shell halves 12a and 12b and the welding of the connections F can be performed with the welding torch T having the same posture. The manufacturing process of the exhaust manifold can be simplified.

  In the present embodiment, the exhaust manifold M used for the in-line four-cylinder engine E is illustrated. However, the present invention is not limited to this and can be applied to any internal combustion engine. Depending on the type, the number of branch pipes 11 can be changed as appropriate.

Further, in the present embodiment, the catalyst carrier unit 14 (see FIG. 1) attached to the exhaust manifold M is exemplified as having a NO _x purification catalyst supported thereon, but the present invention is not limited to the type of catalyst. For example, it may be for attaching a catalyst carrier unit carrying a PM purification catalyst.

  Further, in the method for manufacturing the exhaust manifold M according to the present embodiment, as described above, the gap 24 part, the part where the edges 12c and 12d of the first and second shell halves 12a and 12b are in contact with each other, the branch pipe 11 and welding in the order of the joints of the first and second shell halves 12a and 12b at the joint edge F, the present invention is not limited to this, and after the gap 24 portion is welded The order of the other welding processes is not particularly limited, and the order of the welding processes can be changed as appropriate.

It is a perspective view of the exhaust manifold which concerns on embodiment of this invention. It is a disassembled perspective view of the exhaust manifold of FIG. FIG. 3 is an enlarged view of a portion shown in a circle in FIG. (A) And (b) is a schematic diagram explaining the manufacturing process of the exhaust manifold which concerns on embodiment of this invention. In addition, (b) is sectional drawing in the YY line of (a). It is a schematic diagram explaining the manufacturing process of the exhaust manifold which concerns on embodiment of this invention. (A) is a perspective view of a conventional exhaust manifold, (b) is a cross-sectional view taken along line XX of (a), and (c) is a diagram for explaining a manufacturing process of a conventional exhaust manifold.

Explanation of symbols

11 Branch pipe 12 Shell part (collection pipe)
12a First shell half (first half)
12b Second shell half (second half)
12c Edge 12d Edge M Exhaust manifold

Claims (1)

  An exhaust manifold comprising a plurality of branch pipes and a collection pipe that is joined to the branch pipes and collects exhaust gas flowing in the branch pipes, wherein the collection pipes are arranged side by side at a predetermined interval. Are formed by a first half and a second half sandwiching one end side of the first half and the second half, and the edge of one of the first half and the second half is the other of the edges An exhaust manifold, wherein the branch pipe is shifted in a direction in which the branch pipe extends.

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