DE10220986A1 - Exhaust manifold for IC engines and its manufacturing process has two-part flange of fastener part and heat insulation sleeve for simple modular assembly - Google Patents

Abstract

The manifold has tube ends connected to flanges. A flange (1) consists of a fastener part (2) with passage bores (4) for its connection to a neighboring component, and a heat insulation sleeve (3) fitted into an aperture (5) in the fastener part. At least one of the tube ends (12) extends into the aperture and into a passage (10) of the insulation sleeve. The sleeve is enclosed past the tube length, and sleeve and tube end are welded together. The sleeve is fastened in the fastener part by internal high pressure forming or welding.

Description

The invention relates to an exhaust manifold according to the preamble of claim 1 and a method of manufacture the same according to the preamble of claim 11.

A generic exhaust manifold or a generic Method is known from DE 197 21 092 C1. That's one Exhaust manifold described with a flange, which is a flat Has contact surface. To weld distortions in the material of the flange to avoid being on the flatness of the contact surface - like them For example, at input flanges always to find - have an uncontrollable fault, is in the Through hole of the flange used a nozzle, the There with a joining process low heat input at the flange is attached. At the other end of the neck is with a Exhaust pipe of the manifold with conventional welding high Energy input associated, since there welding distortions in the material do not play a significant role. The nozzle serves as Extension of the exhaust pipe. The neck becomes hot Exhaust gas is applied, causing the flange also great heat is suspended. To the flange over its entire life wear resistant is due to the temperature load an additional alloy, hardening, wear protection Coating or from the outset a higher quality To use material. However, this is a high production cost and costs linked.

The invention is based on the object, a generic Exhaust manifold or a generic method for its To further develop manufacturing to the effect that in a simple manner allows the formation of an exhaust manifold with a flange will meet the requirements for high temperature resistance the flange will meet without any loss in the Functionality arise.

The object is achieved by the features of the invention Claim 1 with respect to the exhaust manifold and by the Features of claim 11 with respect to the method solved.

Due to the fact that the flange is essentially in two parts is formed, the desired characteristics of the Flange in a simple and cost-effective manner to the two Components are divided, with the one component - the Thermal insulation sleeve - the high-temperature strength and the other component - The fastening part - only the connection function to an adjacent component takes over, with the exhaust manifold to be connected. The flange is thus modular with the Modules built thermal insulation sleeve and mounting part. By the arrangement of the thermal insulation sleeve radially between the exhaust pipe and the fastening part increases starting from the Temperature conditions in the hot exhaust gas, the temperature gradient from such that the fixing part only moderate temperatures is exposed. As a result, the attachment part for a cheap materials and manufactured to another Fine blanking or be formed as a deep-drawn sheet metal part, which greatly simplifies the manufacturing process and one cost-effective mass production permits. Any special Claims to external geometric dimensions of the flange for the Connection to an adjacent component can be solely on the Training the heat insulation sleeve are transmitted, preferably produced in the favorable cold extrusion process. In order to Can be used for different assemblies of exhaust manifolds and Attachment - referring to a flange with a single Through hole - almost always the same attachment to the Use come. The constructive deviations are thereby executed the thermal insulation sleeve. Moreover, can be through the Division of the properties and functions of the flange to two Components create a modular system through which it is possible is, just by replacing one of the components different connection geometries or Mounting hole parameters meet. This eliminates the requirement a one-piece shape of the flange for each application to manufacture a special flange. This will be the Production costs significantly reduced.

Advantageous embodiments of the invention can the Subclaims are taken; Otherwise, the invention is based on several embodiments shown in the drawings explained in more detail below; showing:

Fig. 1 is a lateral longitudinal section of a flange of an exhaust manifold according to the invention with a plunging pipe into the flange of the exhaust manifold,

Fig. 2 is a perspective view of a flange of an exhaust manifold according to the invention with two through holes,

Fig. 3 is a lateral longitudinal section of a flange of an exhaust manifold according to the invention in two-part embodiment of the flange with the seal,

Fig. 4 in an exploded view of the flange of FIG. 3 without a seal,

Fig. 5 a perspective view of an exhaust manifold according to the invention in an air-gap-insulated version,

Fig. 6 is a lateral longitudinal section of a flange of the exhaust manifold of FIG. 5 with a sheet metal part,

Fig. 7 is a lateral longitudinal section of a flange of the exhaust manifold of FIG. 5 with a fine blanking part,

Fig. 8 in a lateral longitudinal section a connected to the flange of Fig. 6 pipe of an exhaust manifold according to the invention.

In Fig. 1, a flange 1 of an exhaust manifold of an internal combustion engine of a vehicle is shown, which is composed of a fixing part 2 and a heat insulating sleeve 3 . The fastening part 2 consists in lightweight construction of a deep-drawn sheet metal, for example made of aluminum, and has through holes 4 , by means of which the flange 1 can be fastened via fastening screws to an adjacent component. In principle, it is conceivable that the component may be a cylinder head, so that the flange 1 serves as an inlet flange of the exhaust manifold. In the preferred embodiment, however, the flange 1 is to form an output flange, which is arranged on the side facing away from the cylinder head downstream of the exhaust manifold and on the one hand connected to this and on the other hand with the exhaust line leading to the exhaust. The thermal insulation sleeve 3 is here a Kaltfließpressteil. Both parts, the fastening part 2 and the sleeve 3 , are therefore very repeatable producible and light in weight. The sleeve 3 is introduced into an approximately central passage opening 5 of the fastening part 2 . For this purpose, the sleeve 3 is inserted into the through hole 5 in a simple manner with game and is then attached to this. The fastening process can be a clamping by means of fluidic internal high pressure, with the sleeve 3 expanding plastically radially, while the fastening part 2 only expands elastically and forms an extremely strong press fit on the sleeve 3 due to its springback. This fastening has the advantage that no fasteners are required, which increase the weight of the component, and that the handling is relatively easy. Alternatively, it is conceivable that the heat insulating sleeve 3 is pressed into the fastening part 2 . For this purpose, high forces must be expended and the sleeve 3 are pre-machined by the formation of Einführfasen. Furthermore, of course, a welding is possible, which has the disadvantage that on the one hand, the sleeve 3 or the fastening part 2 must be kept true to the litter during the welding process and that on the other hand by welding at too high heat input distortions in the mounting part 2 arise, if necessary unwanted discard the contact surface and thus complicate the screwing. On the other hand, welding is quick and easy to do. The holding device can be omitted if the joining of the sleeve 3 and the fastening part 2 takes place by a combination of welding with the mentioned bracing or pressing. By this combination, the gas-tightness of the flange 1 is improved.

By a defined position of the sleeve to obtain 3 on the fastening part 2, the sleeve 3 in a protruding on abgaskrümmerabgewandter side of the fastening part 2, section 6, a support shoulder 7, which as a stop for the space formed by the front face 8 of the fastening part 2 counter-stop during the insertion the sleeve 3 is used. On the inside 9 of a passage 10 of the sleeve 3 , a step-like projection 11 is formed, on which a pipe end 12 of an exhaust pipe of the exhaust manifold is supported in a defined position. The tube end 12 immersed while in both the high-torque-like through-hole 5 of the mounting part 2 as such that the insulation sleeve 3 between the fixing member 2 and the tube end 12 12 of time is enclosed in the passage 10 of the thermal sleeve 3 a on the insertion length of the pipe end.

The heat-insulating sleeve 3 protrudes on the side of the flange 1 facing the exhaust gas manifold beyond the fastening part 2 and is welded at its end-side end edge 13 circumferentially in a circumferential seam 28 to the outside 14 of the pipe end 12 . Due to the resulting welding distortions, a sufficient fixation of the fastening part 2 on the sleeve 3 is achieved in addition to the joint connection between the thermal insulation sleeve 2 and the fastening part 2 . The section 6 of the sleeve 3 is tapered away on its outer peripheral surface 15 away from the fastening part 2 . This surface forms the sealing surface to a correspondingly formed counter-sealing surface of a flange of the continuing exhaust line. The conicity provides a large sealing surface in a small space. The final gas-tightness of the flange 1 , or the final gas-tight contact of the sleeve 3 to the fastening part 2 takes place when screwing the flange 1 with the mating flange of the continuing exhaust gas line through the tightening torque.

Incidentally, it is also conceivable to dispense with a support shoulder 7 and instead form on the inside of the through hole 5 of the deep-drawn sheet metal fastening part 2 a latching nose and accordingly on the outside of the sleeve 3 a detent recess or detent groove, whereby after latching the locking elements into each other a montageerleichternde Anti-rotation of the fastening part 2 is given to the sleeve 3 .

From Fig. 2, a variant of the flange 1 can be seen, in which the fastening part 2 instead of a two through holes 5 has. This variant is expedient in exhaust manifolds, which must be formed divided for reasons of space. Their exhaust pipes are brought together near the flange 1 at an acute angle to each other. The fastening part 2 is also formed as a deep-drawn sheet metal part with circumferential flange 16 in order to guarantee sufficient rigidity. Furthermore, the flange 1 riveting nuts 17 which are anchored in the through-holes 4 by riveting indissolubly. The nuts 17 can be arranged there rotatable or non-rotatable. The sleeves 3 are so mechanically expanded to a projecting on abgaskrümmerzugewandter side of the fastening part 2, section 18, to correspond to the geometry of the pipe-gathering of the exhaust pipes of the exhaust manifold. As a result of this geometric matching of the sleeves 3 to the pipe junction, the joint gap between the sleeves 3 and the pipe junctions received by them remains so small that it can easily be gas-tightly bridged by the weld seam of the weld to be made in the sleeves 3 after insertion of the pipe junction. Due to the narrow joint gap and the long-term durability of the weld is given.

A further variant of the flange 1 , Figs. 3 and 4. There, the fastening part 2 lamellar from an embossed upper and a lower part 19 and 20 , which are both formed as fineblanking parts. In order to use the simple production method of punching for relatively thick fastening parts 2 with small through-holes 4 , said disc-shaped division is required. For smaller thicknesses or larger through holes 4 , a one-piece fastening part 2 is conceivable. For the assembly of the flange 1 , a simple executable joining technique is used, in which the fastening part 2 or 19 and 20 of the flange 1 is engaged behind the front side by two axially spaced-apart radial extensions of the thermal insulation sleeve 3 . For this purpose, after insertion of the respective thermal insulation sleeve 3 in the through holes 5 of the superimposed components 19 and 20 of the fastening part 2, the heat insulating sleeve 3 on abgaskrümmerseitig over the upper part 19 of the fastening part 2 protruding end to form an extension representing a collar 21 with the upper part 19 imprinted. Due to the formed on section 6 of the sleeve 3 support shoulder 7 - the second extension - which comes into contact with the bottom 22 of the lower part 20 during insertion, the lamellar fastening part 2 is at embossing on the thermal insulation sleeve 3 to form a captive for the thermal insulation sleeve. 3 and a fixation of the two parts 19 and 20 clamped together. It is of course conceivable, on the one hand, to provide this clamping even with one-piece fastening parts 2 and, on the other hand, to form a bracing embossment there instead of the supporting shoulder 7 . Also, this type of clamping is also possible with the deep-drawn sheet metal variant of the fastening part 2 . In order to further increase the gas-tightness of the modular flange 1 , a sealing ring 24 can be arranged on the exhaust side facing away from the heat-insulating sleeve 3 between the upper side 23 of the support shoulder 7 of the heat-insulating sleeve 3 and the underside of the fastening part 2 or the underside 22 of the lower part 20 .

The production sequence can be followed in two different ways. On the one hand, the fastening part 2 preassembled with the riveting nuts 17 can be pushed over the pipe end 12 , after which the sleeve 3 is in turn pushed onto the pipe end 12 . The fastening part 2 is now withdrawn, so that it bears suitably against the sleeve 3 . Then, the welding of the sleeve 3 with the pipe end 12th Optionally, depending on the structural design of the fastening part 2, this can also be welded to the pipe end 12 . On the other hand, the flange 1 can be pushed after its assembly as a whole on the pipe end 12 , so that this dips both in the fastening part 2 and in the heat insulating sleeve 3 . Thereafter, in the sliding position, the thermal insulation sleeve 3 - optionally also the fastening part 2 - with the pipe end 12 in a device, which are specified the correct position of the through holes 4 , welded. The two welds, the fastening part 2 with the pipe end 12 on the one hand and the heat insulating sleeve 3 with the pipe ends 12 on the other hand, can be done in one operation due to the almost identical position.

In a further embodiment of the invention, FIG. 5 shows an air gap-insulated exhaust manifold 25 which has three input flanges 26 and one output flange 27 . There are for this purpose also other manifold variants conceivable in which only the connected to the output flange 27 pipe end 36 of an exhaust pipe 30 of the manifold 25 is air gap isolated. In principle, an air gap-insulated exhaust manifold consists of an outer part and an inner part radially spaced therefrom. The exhaust manifold 25 is here made of inner tubes, which form the inner part, and two outer shells 31 and 32 which form the outer part, which are welded to the input flanges 26 and the output flange 27 . The inner tubes, which are held in each other in the sliding seat, are in the input flange in a clamping fit on the inside of the outer shells 31 and 32 and are otherwise spaced therefrom by a small gap. While the outer shells 31 and 32 are deep-drawn and welded together at the flanging edges 33 according to the inside arrangement of the inner tubes, the inner tubes are either hydroformed from a tube blank or rolled from blanks and longitudinally welded and bent. It is also conceivable that, instead of the outer shells 31 , 32, a hydroformed tube with different necklaces is used.

The output flange 27 of the exhaust manifold 25 , which forms the interface of the exhaust manifold 25 to the rear exhaust system and is designed as a releasable connection, has a heat-insulating sleeve 3 , whose outer peripheral surface 34 is formed on the side facing away from exhaust gas. Due to this spherical sealing surface angular error between the exhaust manifold 25 and rear exhaust system can be compensated in a simple manner during installation gas-tight. Furthermore, it is advantageous over flanges with planar abutment surfaces that it is possible to dispense with the use of a costly compensating element such as, for example, a corrugated pipe compensator or fabric hoses. In addition, a sealing element between the contact surfaces of the output flange 27 and the corresponding flange of the rear exhaust system omitted. As a result of the modular construction according to the invention of the output flange 27 , as can also be seen in FIGS. 6-8, and the resulting use of different production techniques for the individual components - the fastening part 2 and the thermal insulation sleeve 3 - the production costs of such a ball flange can be minimized because due to the complexity of the design such components can be forged in a complex manner in one-piece form only and then machined.

The output flange 27 can be formed in the version of FIG. 6 with a crimped thermoforming sheet or in the embodiment according to FIG. 7 with a stamped part, ie fineblanking part, as a fastening part 2 . In order to provide a sliding fit to the inner tube 35 of the tube end 36 of the exhaust manifold 25 , the heat insulating sleeve 3 has an annular collar 37 projecting radially inwards in its passage 10 , against which the inner tube 35 of the air gap-insulated tube end 36 is radially supported ( FIG. 8). In order to minimize frictional wear of the inner tube 35 on the annular collar 37 , the passage 38 bounded by the annular collar 37 is conically widened in the direction away from the exhaust gas, so that the abutment of the tube end 36 on the annular collar 37 and thus the friction is very small.

The final manufacturing of the exhaust manifold 25, the inner tube 35 is inserted the tube end 36 in the heat-insulating sleeve 3 with radial support on the projecting into the passage 10 of the sleeve 3 annular collar 37th The outer shells 31 and 32 are simultaneously inserted into the sleeve 3 with radial support of its outer periphery on the Durchlaßwandung 39 above the annular collar 37 , possibly until the end edge of the outer shells 31 , 32 come to rest on the upper end face of the annular collar 37 . Subsequently, the outer shells 31 , 32 are welded directly above the flange 27 with an end face 40 of the sleeve 3 . It is favorable in terms of process economy and also advantageous for the strength of the components to be joined together when the heat-insulating sleeve 3 is welded to the fastening part 2 and to the outer shell 31 , 32 of the pipe end 36 in a common molten bath, so that the thermal insulation sleeve 3 and the Mounting part 2 have a common weld 29 at the pipe end 36 .

In an air gap-isolated exhaust manifold 25 , the decoupling of the attachment function from the heat-resistant property of the flange 27 is particularly effective since the inner tubes are very much heat-stressed by the heat shielding of the outer shells 31 , 32 to the outside and the heat dissipation thus reduced.

Claims (18)

1. Exhaust manifold of an internal combustion engine of a vehicle, the tube ends are connected to at least one flange, characterized in that the flange ( 1 , 27 ) consists of a fixing part ( 2 ) with through holes ( 4 ) for fixing the flange ( 1 , 27 ) an adjacent component and at least one heat insulating sleeve ( 3 ) which is inserted in a passage opening ( 5 ) of the fastening part ( 2 ) that at least one of the pipe ends ( 12 , 36 ) in the through hole ( 5 ) of the fastening part ( 2 ) and the Passage ( 10 ) of the heat insulating sleeve ( 3 ) is immersed, wherein the heat insulating sleeve ( 3 ) between the fastening part ( 2 ) and the pipe end ( 12 , 36 ) over the immersion length of the pipe end ( 12 , 36 ) is bordered away. 2. Exhaust manifold according to claim 1, characterized in that the flange ( 1 , 27 ) arranged on the cylinder head side facing away from the exhaust manifold and is connected to the exhaust pipe leading to the exhaust. 3. Exhaust manifold according to one of claims 1 or 2, characterized in that the fastening part ( 2 ) of the flange ( 1 , 27 ) by two axially spaced-apart radial extensions of the thermal insulation sleeve ( 3 ) is engaged behind the front side. 4. Exhaust manifold according to one of claims 1 to 3, characterized in that the heat-insulating sleeve ( 3 ) and the fastening part ( 2 ) have a common weld ( 29 ) at the pipe end ( 12 , 36 ). 5. Exhaust manifold according to one of claims 1 to 4, characterized in that at least the pipe end ( 36 ) is air gap insulated and that the heat insulating sleeve ( 3 ) in its passage ( 10 ) radially inwardly projecting annular collar ( 37 ), on which the inner tube ( 35 ) of the air gap insulated pipe end ( 36 ) is radially supported, wherein the heat insulating sleeve ( 3 ) with the outer shells ( 31 , 32 ) of the air gap insulated pipe end ( 36 ) is welded, the end with the circumference at the passage wall ( 39 ) of the sleeve ( 39 ) 3 ) is applied. 6. Exhaust manifold according to claim 5, characterized in that the annular collar ( 37 ) limited passage ( 38 ) is flared in exhaust gas away from the direction. 7. Exhaust manifold according to one of claims 1 to 6, characterized in that on abgaskrümmerabgewandter side from the fastening part ( 2 ) projecting portion ( 6 ) of the thermal insulation sleeve ( 3 ) has a spherical outer peripheral surface ( 34 ). 8. Exhaust manifold according to one of claims 1 to 7, characterized in that on the exhaust manifold facing side from the fastening part ( 2 ) projecting portion ( 18 ) of the thermal insulation sleeve ( 3 ) is widened. 9. Exhaust manifold according to one of claims 1 to 8, characterized in that on the outer circumference of the heat insulating sleeve ( 3 ) is formed a trough and in that on the wall of the through hole ( 5 ) of the fastening part ( 2 ) is formed a nose in the trough the heat insulation sleeve ( 3 ) can be latched. 10. Exhaust manifold according to one of claims 1 to 9, characterized in that on Abggaskrümmerabgewandter side of the thermal insulation sleeve ( 3 ) between one of the fastening part ( 2 ) projecting portion ( 6 ) of the thermal insulation sleeve ( 3 ) and the fastening part ( 2 ) has a sealing ring ( 24 ) is arranged. 11. A method for producing an exhaust manifold, the tube ends are welded to at least one flange, characterized in that the flange ( 1 , 27 ) of a fastening part ( 2 ) with through holes ( 4 ) for fastening the flange ( 1 , 27 ) to a adjacent component and at least one heat insulating sleeve ( 3 ) is formed, wherein the heat insulating sleeve ( 3 ) is inserted into a through opening ( 5 ) of the fastening part ( 2 ) and secured thereto, that the flange ( 1 , 27 ) on at least one of the pipe ends ( 12 , 36 ) is pushed, so that this dips both in the fastening part ( 2 ) and in the heat insulating sleeve ( 3 ), wherein this between the fastening part ( 2 ) and the pipe end ( 12 , 36 ) over the immersion length of the pipe end ( 12 , 36 ) is bordered, after which in the sliding position, the heat insulating sleeve ( 3 ) with the pipe end ( 12 , 36 ) is welded. 12. The method according to claim 11, characterized in that the heat insulating sleeve ( 3 ) in the fastening part ( 2 ) is pressed. 13. The method according to claim 11, characterized in that the heat insulating sleeve ( 3 ) is inserted into the fastening part ( 2 ) with play and then attached thereto. 14. The method according to claim 13, characterized, that the fastening by clamping by means of fluidic Hydroforming takes place. 15. The method according to claim 13, characterized, that the fastening takes place by welding. 16. The method according to claim 15, characterized in that the welding of the thermal insulation sleeve ( 3 ) with the fastening part and with the tube end ( 12 , 36 ) takes place in a common molten bath. 17. The method according to claim 13, characterized in that the heat insulating sleeve ( 3 ) on at least one on the fastening part ( 2 ) projecting end with the fastening part ( 2 ) is embossed to form a collar ( 21 ), wherein the fastening part ( 2 ) the thermal insulation sleeve ( 3 ) is clamped. 18. The method according to any one of claims 11 to 17, characterized in that the exhaust manifold ( 25 ) is formed at least at its pipe end ( 36 ) air gap insulated, wherein the inner tube ( 35 ) of the pipe end ( 36 ) in the heat insulating sleeve ( 3 ) under radial Support on a in the passage ( 10 ) of the sleeve ( 3 ) projecting annular collar ( 37 ) is slidably inserted and wherein the outer shells ( 31 , 32 ) in the sleeve ( 3 ) with radial support on the passage wall ( 39 ) above the annular collar ( 37 ) is inserted and then welded to an end face ( 40 ) of the sleeve ( 3 ).