DE102005025735B3 - Welded joint of air gap insulated waste gas bend useful in automobile construction has connecting flange, inner part for guiding hot gases and outer jacket - Google Patents

Abstract

Welded joint of an air gap insulated waste gas bend (sic) with a connecting flange, where the bend has a inner part for guiding the hot gas and an outer jacket distanced radially from the inner part. The end of the inner part is located in an opening in the connecting flange, while the cutoff (sic) edge of the corresponding end of the outer jacket is outside this opening. The connecting flange is an individual flange at the end of the bend, has a collar for accommodating the end of the inner part, and is obtained from deep drawn sheet. The inner part (4) is welded to composite flange (3) via a through weld of the outer jacket (5).

Description

The The invention relates to a welded joint of a Air gap insulated exhaust manifold with a connecting flange according to the preamble of claim 1.

A generic welded joint is from the DE 199 52 648 C2 known. Therein, an air gap-insulated shell manifold is described, which is welded in various ways with a connecting flange to form a welded joint. This connection flange is designed as a block flange, which is connected together with all cylinder head side ends of the shell manifold. On the cylinder head side facing away from the block flange of the shell manifold is welded to this in a ternary connection, that is, that a connection is to be achieved, in which the connecting flange, the outer shell and the inner part of the shell manifold are joined together in a common weld. For this purpose, several variants are executed. For example, the outer shell has at least one radial recess at its ends in the region of the weld to be produced on a part of its circumference, so that the inner part of the shell manifold can be seen from the outside. Like from the 5 can be seen, the welding takes place across the recess, wherein the inner part is detected only in the region of the recess, so that there is only a three-way welding. Due to this partial connection of the inner part, however, strength disadvantages for the welded composite arise, so that the resistance of the exhaust manifold in engine operation against mechanical and thermal loads is not very large. Furthermore, the welding is associated with great expense, since their execution is difficult due to the reduced accessibility in the immediate vicinity of the connecting flange.

In a further variant of the known shell manifold, the 7 is illustrated, the outer shell is formed such that the end edges of the ends of the outer shell are recessed to form a circumferential weld gap of the cylinder head side facing away from the connecting flange. As in the previous embodiment, the accessibility for the welding is difficult here, in addition, a highly accurate positioning of the end edges of the outer shell ends is required, which otherwise leads to insufficient welding of the inner part with the other two Schweißverbundpartnern, the connecting flange and the outer shell, or the connecting flange with its two welded composite partners, the outer shell and the inner part, leads. With this exact positioning a very high production effort is connected.

Of the Invention is based on the object, a generic welding composite to further develop that with a simplified production one possible optimum strength of the welded joint partners is guaranteed to each other.

The Task is inventively by the features of claim 1 and by the features of claim 2 solved.

Nice due to the fact that the welded joint according to the invention of the air gap isolated exhaust manifold has a single flange as a connecting flange, the only one single end of the exhaust manifold is assigned, the attachment of a circumferential weld considerably easier because of accessibility is improved. The fact that the connecting flange also has one to the exhaust manifold has pointing collar, where the welding is done, the place of welding from the the sealing surface including for a weld hard to reach Flange plane retracted, ensuring accessibility be facilitated to a considerable extent, which in the same way the Production of the welded joint especially simplified. The displacement of the place of welding the mentioned Flanschebene out further offers the advantage that the sealing surface of Connecting flange due to the distance to the weld not from the sweat heat is influenced and can not be forgiven. An afterthought with big Effort associated straightening the sealing surface thus eliminated in a simple manner. Also in the welded joint according to the invention arrive at its production no welding spatter in the interior of the exhaust manifold, on the walls they could get stuck. This is simply prevented by the welding of cylinder side facing away from the connecting flange and thus not on the opening the ends are directed, let alone inside the bore of the Connecting flange executed becomes. Sweat spatter, the otherwise on the walls set the interior of the inner part of the exhaust manifold, dissolve due to vibrations and thermal influences in engine operation, according to which they through the exhaust flow as projectiles an exhaust gas converter integrated in the exhaust system and / or fed to an exhaust gas turbocharger and cause serious damage after colliding with them, the under circumstances to the utter Function unfit to lead.

In the one variant of the invention according to claim 1 proposes the end of the outer jacket in a dull thrust the front of the collar. This will cause the positioning the exhaust manifold clearly defined to the single flange in a simple manner, wherein the relative position by the stop on the front side of the collar automatically at found the preliminary assembly of the welding partners for the welding becomes. The inner part of the exhaust manifold Although it is completely radial from the outer shell outward covered, however, is the formation of a three-way connection between the single flange, the inner part and the outer shell the exhaust manifold achieved in that at the location of the stop, the inner part of a penetration of the outer jacket welded to this and the connecting flange. The penetration can peripherally continuously done so that a high strength of the composite partners to each other guaranteed is. Furthermore, a complete Gas-tightness of the welded joint achieved as a result of the continuous welding no exhaust gas between the inner part and the outer shell of the exhaust manifold pass can. An entry of exhaust gas into the otherwise open gap would heat already at an early date out of the exhaust stream to the outside dissipate into the environment, what heat however for an early one Starting an exhaust gas converter integrated into the exhaust gas system is urgently needed.

In the other variant of the invention according to claim 2, the outer jacket at its end edge and / or the collar at least one axial projecting punctual spacer, which also when pushing together the exhaust manifold with the connecting flange automatically for a defined relative position between connection flange and exhaust manifold ensures. Through the spacer, the Depending on the mounting location, either on the trailing edge or the Front side of the opposite Stand up connection partner, the end edge of the outer shell over the remaining circumference from the end face of the collar of the connecting flange forming a welding gap, which remains at least substantially the same width in the circumferential direction, spaced. At the place of the welding gap, the inner part, the Connecting flange and the outer jacket in a simple manner to form a smooth running Weld welded. Due to the welding gap is a penetration of the outer jacket not required here. By a corresponding axial length of Spacer, the manufacturing tolerances of the connecting flange or of the outer jacket exceeds the exhaust manifold, the formation of a sufficient welding gap is always ensured. The Width of the welding area, So its extension in the axial direction, in a simple manner on the length and the location of the high-precision formable spacer, whereby the weld always can be put in the right place, so that the weld without Task of process safety can be automated. Furthermore is guaranteed that the inner part and the outer shell the exhaust manifold in the circumferential direction at each point with the collar and thus with the Connection flange welded connected are, from which an optimal strength of the welded composite partners to each other. Of course, this does not apply to the spacer itself, which represents an interruption of the welded joint. Since the Spacer but in its width, that is in the circumferential direction of the collar or the end edge of the outer jacket of the exhaust manifold almost can be made arbitrarily small, this interruption affects on the strength and gas tightness of the welded joint practically not and is therefore negligible.

In a preferred embodiment of the welded joint according to the invention according to claim 3, the single flange of a deep-drawn sheet metal part. In contrast to forging or punching, the deep drawing of the single flange allows almost any three-dimensional design options, so that the Collar and the Flanschbohrungskontur already in the production of Flange exactly to the dimensions of the inner part and the outer shell the exhaust manifold can be matched. Reworking such as grinding the bore wall omitted in a simple way completely. It is only to create a through hole of the bore of the connecting flange only a downstream punching necessary. The production the single flange of a deep-drawn sheet metal part is also to the effect that starting from a sheet metal blank very low wall thicknesses can be displayed, which give the single flange a low weight.

In a further particularly preferred embodiment of the invention according to claim 4, the collar of the single flange aufgetulpt on a portion to form an extension of the collar cross-section, wherein the end of the inner part of the exhaust manifold is disposed in the extension and has a larger inner diameter than that of the non-recessed collar section. The bulge, which is accompanied by a cross-sectional enlargement of the collar, is relatively easy to perform by deep drawing. The expansion of the collar cross-section and the arrangement of the inner part in this extended space is achieved that the end edge of the inner part is displaced out of the flow path of the exhaust gas, whereby the exhaust gas can flow freely through the exhaust manifold. Because of that, the Improved acoustics of the exhaust line and engine performance in engine operation.

In a further particularly preferred embodiment of the invention according to claim 5, the spacer is formed knob-shaped prior to welding and in the molten bath of the weld after that dissolved. This is not only in the welding gap the welding executed but also about welded away the spacer, which is so little massive is designed so that it dissolves under the sweat heat. This results in a full extensive welding of inner part, outer jacket and the collar of the connecting flange. In this way, the optimum strength of the welded joint partners guaranteed to each other without compromise.

In a further preferred embodiment of the invention according to claim 6 is the spacer by a wave crest of a wavy course of the End edge of the outer jacket or the collar. With the wave mountain it is possible, the Spacers massive and at the same time form only selectively, with a true point contact between the collar and the outer shell will be produced. Through the point contact, the smallest possible investment allows the connection partner to each other, a weld is achieved, the almost in full along the end edge of the collar or the outer jacket end runs. Here, too, optimum strength of the welded composite partners to each other and the above mentioned Guaranteed gas tightness. The welding gap decreases in width in the area of the wave mountain, but becomes the welding anyway Completely, if the width of the molten bath and thus the intended weld the width the remaining equal width welding gap corresponds. Thereby, that the welding area on the same width remained welding gap section of greater width is tuned, the narrower welding gap on Wellenberg during the circumferential weld also detected. The production of such a shaped end edge is easily by a parabolic or wavy trimming executed the collar or the end of the outer jacket.

following the invention with reference to several shown in the drawings embodiments explained in more detail.

there shows:

1 3 is a perspective view of a sectional view of a welded composite according to the invention with a through-welding of the outer jacket of the exhaust manifold,

2 in a longitudinal section of the welded joint 1 wherein the left half of the figure reflects the state of the welded joint before welding and the right half of the figure reflects the state of the welded joint after welding;

3 in a longitudinal section, a welded joint according to the invention, wherein in the figure left half the state of the welded joint before welding at a distance of the outer jacket to the connecting flange and rechtsschälftig the figure of the state of the welded joint after welding is shown

4 in a perspective view of a welded joint according to the invention prior to welding with spacers formed on the outer jacket of the exhaust manifold,

5 in a perspective view of a welded joint according to the invention before welding with formed on the connecting flange spacers.

In 1 is a welded composite 1 an air gap insulated exhaust manifold 2 with a connecting flange 3 shown, wherein the exhaust manifold 2 from a hot gas leading inner part 4 and an outer shell spaced therefrom 5 consists. The connecting flange 3 that's here for the exhaust manifold 2 to attach to an engine cylinder head is formed as a single flange, which in each case only a single end 6 the exhaust manifold 2 assigned. The connecting flange 3 , which consists of a deep-drawn sheet metal, points to the exhaust manifold 2 facing side 7 a to this extending collar 8th on. The collar 8th surrounds a central hole 9 of the connecting flange 3 , which is the passage for the exhaust gas from the cylinder head into the exhaust manifold 2 forms. The collar 8th is further on a bend facing end portion 10 aufgetulpt, causing the section 10 opposite the rest of the collar 8th forming a beveled paragraph 11 cross section is extended. To achieve the positioning of the welding partners, the inner part 4 and the outer coat 5 the exhaust manifold 2 as well as the connecting flange 3 , to each other for the subsequent welding of the exhaust manifold 2 with the connecting flange 3 plugged together. Here's how special in 2 is clear, the end 12 of the inner part 4 in the collar 8th plugged in, this end 12 in the inflated extension of the collar 8th lies. The end 12 has a larger inner diameter than that of the untufted collar section 13 and is with its trailing edge 14 axially from the heel 11 of the end section 10 spaced. This distance allows the inner part 4 during engine operation vibration and thermal movements in the direction of the connecting flange 3 perform without encountering a resistance due to then occurring tensile forces on the weld 19 between the inner part 4 , the connecting flange 3 and the outer jacket 5 and thus on the strength of the welded joint 1 would have a damaging influence. As a result of the insertion of the inner part 4 in the collar 8th is the end 12 of the inner part 4 in the hole 9 of the connecting flange 3 arranged. The inner part 4 and the outer jacket 5 are each formed by two deep-drawn and then welded shells, wherein the inner part 4 in the outer jacket 5 is positioned so that by suitable radial spacing of the inner part 4 to the outer jacket 5 an air gap 15 is formed, which is the inner part 4 almost completely surrounds and largely prevents the exhaust heat is released after exiting the cylinder head to the environment. The inner part 4 and the outer jacket 5 However, they can also consist of one or more tubes, which are formed according toforform by hydroforming.

While the end 12 of the inner part 4 in the collar 8th is inserted, is the trailing edge 16 the corresponding end 17 of the outer jacket 5 outside the hole 9 located. This beats the end 17 with a dull push on the front 18 of the collar 8th at.

In the inserted position of the welded composite partner is now the outer jacket 5 and the inner part 4 together with the connecting flange 3 on the exhaust manifold 2 facing side 7 of the connecting flange 3 outside his hole 9 at the location of the stop of the outer shell 5 at the front 18 of the collar 8th welded. To the inner part 4 that from the outer coat 5 is covered to the outside, to integrate into the weld, the outer jacket 5 by welded. The weld 19 thus extends through the outer jacket 5 through into the inner part 4 into it.

In contrast to the previous embodiment suggests in the off 3 to 5 apparent variant of the invention, the outer jacket 20 not on the front side 21 of the collar 22 but is from this under formation of a welding gap 23 defined spaced. About the welding gap 23 the subsequent welding will have unimpeded access to the inner part 24 the exhaust manifold 25 What makes the welding of the three welding partners to each other easier and a through-welding of the outer jacket 20 no longer necessary. Around a defined welding gap 23 in a simple way, is at the trailing edge 24 of the outer jacket 20 an axially projecting point spacer 25 trained or arranged. The spacer 25 can be at the trailing edge 24 molded, secured by mechanical connections or by suitable trimming of the terminal edge 24 be created. At the end edge 24 can be one or more in the circumferential direction of the trailing edge 24 staggered spacers 25 to be appropriate. According to 4 that the welded joint 26 before the weld is reflected in its inserted position, is the spacer 25 nub-shaped. Although it is conceivable, the weld following the spacer 25 make, here is the spacer 25 detected by the weld and dissolved in the weld pool of the weld. When welding, which runs as in the previous embodiment circumferentially, the welding gap 23 through the weld 27 closed and the inner part 28 the exhaust manifold 29 , the connecting flange 30 and the outer jacket 20 the exhaust manifold 29 at the point of the welding gap 23 welded together. In modification to the spacer 25 can optionally or additionally on the front side 21 of the collar 22 of the connecting flange 30 a punctual spacer 31 be educated. This will be in 5 clarified, with the spacer 31 through a wave crest of a wavy course of the front side 21 forming end edge of the collar 22 is formed. The spacer 25 of the outer jacket 20 may also be formed as a wave crest, the end edge 24 to parabolic or wavy cropped.

At this point it should be finally mentioned that the connecting flange 3 . 30 may also be an output flange, that is, a flange, the exhaust manifold 2 . 29 connects with the rest of the exhaust system. The connecting flange 3 . 30 can also consist of a forged or cast solid material, the collar 8th . 22 is machined from the solid material. The same applies to the formation of the cross-sectional enlargement of the collar 8th . 22 This is created by milling or turning an exhaust manifold to the open annular groove. Furthermore, it should be emphasized that the deep-drawn connection flange 3 . 30 due to the low wall thickness which can be set during deep-drawing, is particularly well suited for welding, in particular through-welding, since the collar can be melted quickly at the location of the stop or the welding gap and thus results in a weld pool, via which the connection between the inner part, the outer jacket and the connecting flange can be achieved faster. Furthermore, the welding heat can not be removed so quickly from the site of the weld As with a thick cast or forged flange, so that it can also be saved in the welding for the production of the welded joint time and energy.

Claims (6)

A welded joint of an air gap insulated exhaust manifold with a connecting flange, wherein the exhaust manifold consists of a hot gas leading inner part and an outer shell radially spaced therefrom, wherein an end of the inner part disposed in a bore of the connecting flange and the end edge of the corresponding end of the outer shell is located outside the bore, and wherein outer shell and inner part are welded together with the connecting flange on the exhaust manifold side facing the outside of the bore of the connecting flange, characterized in that the connecting flange ( 3 . 30 ) is a single flange, the only one end ( 6 ) of the exhaust manifold ( 2 . 29 ) and the one to the exhaust manifold ( 2 . 29 ) pointing collar ( 8th . 22 ) into which the end ( 12 ) of the inner part ( 4 . 28 ) is plugged in that the end ( 17 ) of the outer jacket ( 5 ) in a blunt impact on the front side ( 18 ) of the collar ( 8th ) abuts, and that at the point of the stop the connecting flange ( 3 ) with the outer jacket ( 5 ) and the inner part ( 4 ) is welded, wherein the inner part ( 4 ) via a through-welding of the outer jacket ( 5 ) on this and the connecting flange ( 3 ) is welded. Welding composite according to the preamble of claim 1, characterized in that the connecting flange ( 3 . 30 ) is a single flange, the only one end ( 6 ) of the exhaust manifold ( 2 . 29 ) and the one to the exhaust manifold ( 2 . 29 ) pointing collar ( 8th . 22 ) into which the end ( 12 ) of the inner part ( 4 . 28 ) is inserted, that at the trailing edge ( 24 . 21 ) of the outer jacket ( 20 ) and / or the collar ( 22 ) at least one axially projecting point spacer ( 25 . 31 ) is formed, which has a welding gap ( 23 ) between outer jacket ( 20 ) and collar ( 22 ), and that the inner part ( 28 ), the connecting flange ( 30 ) and the outer jacket ( 20 ) at the location of the welding gap ( 23 ) are welded together. welded joint according to one of the claims 1 or 2, characterized in that the single flange of a deep-drawn sheet metal part exists. Welding composite according to claim 3, characterized in that the collar ( 8th . 22 ) of the individual flange ( 3 . 30 ) on a section ( 10 ) is made to form an extension of the collar cross-section, wherein the end ( 12 ) of the inner part ( 4 . 28 ) of the exhaust manifold ( 2 . 29 ) is arranged in the extension and has a larger inner diameter than that of the non-flared collar portion ( 13 ). Welding composite according to one of claims 2 to 4, characterized in that the spacer ( 25 ) is formed knob-shaped before the welding and dissolved in the molten pool of the weld. Welding composite according to one of claims 2 to 4, characterized in that the spacer ( 31 ) by a wave crest of a wavy course of the trailing edge ( 24 . 21 ) of the outer jacket ( 20 ) or the collar ( 22 ) is formed.