EP2250365A1

EP2250365A1 - Fuel distributor assembly

Info

Publication number: EP2250365A1
Application number: EP09720768A
Authority: EP
Inventors: Burkhard Harhoff; Markus Schmidt; Ludwig WIEDENLÜBBERT; Michael GIEßEL
Original assignee: Poppe and Potthoff GmbH
Current assignee: Poppe and Potthoff GmbH
Priority date: 2008-03-11
Filing date: 2009-03-04
Publication date: 2010-11-17
Anticipated expiration: 2029-03-04
Also published as: JP2011513646A; US8419073B2; BRPI0909753B1; EP2250365B1; BRPI0909753A2; US20110012342A1; DE102008013575B3; WO2009112191A1; JP5221684B2

Abstract

The invention relates to a fuel distributor assembly, having a distributor tube (10) and at least one connecting nipple (12) welded to the distributor tube for connecting a branch line to a cross-bore (16) leading through the wall of the distributor tube (10), wherein an outside of the connecting nipple transitions into the outside of the distributor tube via an annular groove (26), which at least partially surrounds the outside of the connecting nipple and is integrally molded into the outside of the distributor tube (10).

Description

Fuel rail assembly

The invention relates to a fuel rail assembly with a manifold and at least one welded to the manifold connecting nipple for connecting a branch line. The invention further relates to a manifold, a connection nipple for producing such a fuel rail assembly and method for producing a fuel rail assembly.

In the preamble of claim 1 is based on a Kraftstoffvertεilerbaugruppε, as described for example in EP 0 866 221 Bl.

Such fuel rail assemblies are used for example in so-called common rail injection systems for diesel engines. In this case, the distributor tube is acted upon by a high-pressure pump forth with high-pressure fuel, which is fed to individual nozzles connected by branch lines connected to the manifold. Ever higher demands on the exhaust gas quality of the engines require an increase in the injection pressures and thus the pressure resistance of such fuel rail subassemblies. In the meantime, pressures in the order of 2500 bar are envisaged.

From DE 10 2005 043 015 Al a generic fuel rail assembly is known, the connection nipple has a wall, the inside and outside of which tapers towards the end to be welded to the manifold and ends in an annular projection. The annular projection is insertable into an annular groove formed on a flat outer circumferential surface of the manifold. By fitting the projection into the groove, the welding current can be concentrated on the projection during an electric welding.

From the likewise generic DE 102 21 653 Al a fuel rail assembly is known, the connection nipple ends at its end to be welded to a formed in the outer surface of the manifold groove to be welded in a peripheral tip.

From EP 1 182 670 A1 a reactor pressure vessel is known in which a forged nozzle housing with a forged nozzle is integrated. The nozzle includes a bore which leads from an inner side of the nozzle housing to the outside. The nozzle housing contains on its outer side, a reinforcing region into which the nozzle is machined such that an outer end of the nozzle does not extend beyond an outer surface of the reinforcing region. In the reinforcing region coaxial with the nozzle bore, a circumferential groove is incorporated, which allows access to an outer end of the nozzle during welding.

From DE 101 52 261 Al a high-pressure fuel accumulator with a hollow base body and at least one transverse bore with a connection opening to the interior of the base body is known. To increase the compressive strength, one or more indentations and / or recesses for stress relief of the pressurized high-pressure accumulator are preferably formed in the vicinity of the transverse bore on the outer and / or inner surface of the hollow body.

The invention has for its object to provide a fuel rail assembly, the pressure resistance compared to conventional fuel manifold construction groups is increased.

This object is achieved with a fuel rail assembly according to claim 1.

The inventively provided annular groove leads to a considerable increase in the load capacity of the connection nipple.

The subclaims 2 to 8 are directed to advantageous embodiments and further developments of the fuel distributor assembly according to the invention.

With the features of claim 6, the fuel rail assembly can be advantageously made from the manifold and the first separately prepared nipples.

The features of claims 7 and 8 characterize a usable for the fuel rail assembly according to the invention manifold.

Claims 11 and 12 are directed to a nipple as it can be used for the fuel rail assembly according to the invention. Claims 13 to 15 indicate methods for producing a fuel distributor assembly according to the invention.

The invention is explained below with reference to schematic drawings, for example, and with further details.

In the figures represent:

1 is a longitudinal section through a part of a manifold with welded nipple, cut in the plane I-I of Fig. 2,

2 shows a cross section through the arrangement of FIG. 1, cut in the plane II-II of FIG. 1,

3 shows the view of the distributor tube of FIG. 1 without the connecting nipple welded thereto, FIG.

4 shows the connection of the distributor tube according to FIG. 2 without the connection nipple welded therewith, FIG.

5 shows a cross section through a connection nipple before it is welded to the distributor tube,

6 is a view similar to FIG. 1 of a modified embodiment,

Fig. 7 is a view similar to Fig. 6 of another embodiment, and

Fig. 8 is a similar to Fig. 1 view of another embodiment.

Fig. 1 shows a section of a manifold 10, which may be welded along its length with a plurality of nipples 12. At each nipple 12, a branch line, not shown, connected in a conventional manner, via which an injection nozzle, in particular provided on a diesel engine injection nozzle, is supplied with fuel under high pressure. Through the distributor tube 10 extends along its length a longitudinal bore tion 14, from the individual transverse bores 16 pass through the wall of the manifold 10, for example in the radial direction. In Fig. 1, such a transverse bore 16 is shown, for example, starting from the longitudinal bore 14 extends stepwise and ends in a concave mouth 18.

Around the orifice 18, preferably concentric with the orifice 18, a connection recess 20, preferably by machining, is formed on the outside of the distributor tube 10, wherein a milling tool can be oriented on the transverse bore 16. The recess 20 has a the muzzle 18 facing, preferably parallel to the axis of the transverse bore 16 directed inside or inside wall 22, to which a preferably perpendicular to the axis of the longitudinal bore 14 directed bottom side or bottom wall 24 connects, via an annular groove 26 in a turn preferably parallel to the axis of the transverse bore 16 extending outside or outer wall 28 passes.

The connection nipple 12 is welded to the annular groove 26 facing region of the bottom wall 24 of the connection recess 20.

FIG. 3 shows the part of the manifold 10 shown in FIG. 1 prior to welding to the fitting nipple 12. FIG. 4 shows the part of the manifold 10 shown in FIG.

According to FIGS. 3 and 4, the annular connection recess 20 is formed at a depth such that the inner wall 22 and at least the part of the bottom wall 24, with which the connection nipple 12 is welded, extend completely around the transverse bore 16. The outer wall 28 and the outer wall 28 freestandingly connected to the bottom wall 24 annular groove 26 are only in the apex region of the outside of the manifold 10, ie in the areas of the outside, which are adjacent to the mouth 18 of the transverse bore 16 parallel to the axis of the manifold 10, complete educated. From these areas, the height of the outer wall 28 and then the depth of the annular groove 26 progressively decrease until, in the regions of the outer surface of the manifold 10 adjacent the mouth 18 transverse to the axis of the manifold 10, the annular groove 26 and the outer wall 28 completely missing, as shown in Fig. 4. In this preferred embodiment of the connection As a result, the wall of the distributor tube 10 is only minimally weakened or removed.

3, the width of the annular groove 26, measured at the level of the bottom wall 24, for example, about half as wide as the entire width of the Anschlußaus- recess 20 and the distance between the inner wall 22 and the outer wall 28th The annular groove 26 is preferably designed such that it continuously extends the outer wall 28 and transitions arcuately in cross-section, for example circular arc, into the bottom wall 24, wherein the region of the wall of the annular groove adjoining the bottom wall 24 advantageously leads to the axis of the transverse bore 16 can be inclined and the annular groove can extend in cross-section over a circumferential angle <180 °. The cross-sectional shape of the annular groove does not have to be circular in shape; it can be elliptical, U-shaped or otherwise suitable.

FIG. 5 shows a cross section through the connecting nipple 12 before it is welded to the distributor tube 10. The connecting nipple 12 is an overall cylindrical component having an inner wall which, according to FIG. 5, initially has a conically tapering region 30 from above cylindrical region 32 with axially parallel inner wall in a conically widening region 34 passes.

The outside of the connecting nipple 12 in the illustrated example according to FIG. 5 preferably has an external thread 36 in its upper region, and merges via a conically widening region 38 into a cylindrical region 40, which via a tapered region 42 into an annular contact surface 44, which is preferably directed approximately perpendicular to the axis of the connecting nipple 12 and connects the region 42 with the inside region 34. The annular contact surface 44 may be formed as a more or less narrow cutting edge or as a distinct annular surface with a small width. The contact surface 44 is such that, when inserting the connection nipple 12 into the connection recess 20, it comes completely into contact with the bottom wall 24, preferably radially within the transition between the bottom wall 24 and the annular groove 26. If the nipple 12 is inserted into the connection recess 20, it is preferably welded by capacitor discharge welding to the manifold 10, wherein the contact surface 44 widened by melting the material and a designated in Fig. 1 at 46 welding zone is formed, in which the end material of Connection nipple 12 is welded to the material of the manifold 10 in the bottom wall 24.

As can be further seen from FIG. 1, the dimensioning of the connection nipple 12 is advantageously such that the inside of the connection nipple 12 does not touch the inside wall 22 of the connection recess 20 and that the ring groove 26 at best only to a small extent in its radially inner region from the material which melts during welding is covered or filled.

With the described embodiment, a high-strength connection between the connecting nipple 12, which is formed at its end portion facing the manifold 10 in the manner of an annular bead 48 (FIG. 5) tapering conically towards the distributor tube 10, and the distributor tube 10 are reached, their strength surprisingly is significantly increased by preferably with a curved bottom extending annular groove 26.

When welding the connection nipple 12 to the manifold 10 is not necessarily a capacitor discharge welding method used, but the welding can be done by laser welding and other known welding methods. It is advantageous to tune the front end of the connecting nipple 12 to the bottom wall 24 in such a way that the annular groove 26 is maintained and the smallest possible notch effect emanates from the welding point, in particular on the outside of the connecting nipple. For this, a small angle β (FIG. 5) is advantageous.

In the foregoing, an embodiment of the fuel rail assembly has been described in which the annular groove 26 has been formed in the terminal recess 20 prior to welding the terminal nipple 12 to the bottom wall 24 of the terminal recess 20. Alternatively, the annular groove 26 can be formed only after the welding of the connecting nipple 12 with the outside of the manifold 10 and the bottom wall 24 of the connection recess 20, for example by milling. In this case, the connection recess 20 are first formed with respect to Fig. 3 lesser radial extent in the direction away from the transverse bore 16, so that the nipple connection 12 in the Anschlussaus- 20 can be used. During the subsequent welding of the connection nipple 12 to the distributor tube 10, the welding zone 46 is formed whose radial extension through the flow of the material is generally greater than the radial extent of the contact surface 44 of the not yet welded connection nipple 12. After welding the connection nipple 12, the Ring groove 26 is formed by, for example, radially outside of the connection nipple 12 under axial feed movement a milling tool is moved around the connection nipple 12 around. In this case, with a correspondingly large formation of the welding zone 46, part of the material of the welding zone can be removed, so that the undercut visible in FIG. 1 does not necessarily have to be present in the transition from the connecting recess 20 to the radial outside of the connecting nipple 12. The depth of the annular groove is advantageously deeper than the previously formed connection recess 20.

The visible in Fig. 1 distance between the inside of the connection nipple 12 and the inner wall 22 of the connection recess 20 is advantageously relatively small for proper centering of the connection nipple 12 in the connection recess 20. A contact should not be present in this area, however, in order to ensure that the welding takes place only in the region of the bottom wall 24 of the connection recess 20.

Fig. 6 shows an embodiment in which the manifold 10 and the connection nipple 12 are made for example by forging as a unitary material assembly. In contrast to the embodiment of FIG. 1 is missing due to the one-piece design of the clearly visible in Fig. 1 annular cavity between the inside of the connection nipple 12 and the inner wall 22 of the connection recess, since in the embodiment of FIG. 6, the connection recess is missing altogether. After forging, the outside of the connecting nipple 12 passes directly into the outside or surface of the distributor tube 10. In the transition region, for example, by milling, the annular groove 26 is formed, which has a cross-section similar to that shown in Fig. 1.

The embodiment according to FIG. 7 differs from the embodiment according to FIG. 6 in that the radially inner side of the annular groove 26 is free of undercut into the outside the connecting nipple 12 passes, wherein the inside wall of the annular groove 26 extends approximately parallel to the axial direction of the connecting nipple or the transverse bore 16.

FIG. 8 shows a view similar to FIG. 1 of a further embodiment of the assembly according to the invention. This embodiment has, in addition to the annular groove 26, a further inner annular groove 50, via which the inside of the connecting nipple 12 merges into the outside of the distributor tube 10. The inner annular groove 50 surrounds the mouth 18 of the transverse bore 16 at a distance such that the mouth 18 is sufficiently stable for pressing a front end of a branch pipe attached to the connection nipple 12, without the wall of the radially inner side of the inner annular groove 50 is deformed.

Similarly, as the annular groove 26 formed in the connection recess 20, for example, can be milled after the connection recess 20 is formed in the manifold (see FIG. 3), and the inner annular groove 50 can be introduced into this connection recess 20, so that the radially inner Side of the inner annular groove 50, the inner wall 22 of the connection recess 20 extends into the manifold 10 into it. Alternatively, like the outer annular groove 26, the inner annular groove 50 can be formed only after the welding of the connecting nipple 12 to the connecting recess 20. Even with the one-piece with the manifold 10 training the connection nipple 12, the inner annular groove 50 can be milled in addition.

The angle of inclination α and β shown in FIG. 5 of the inside or outside of the conically tapered region 42 and the radial width of the contact surface 44 are selected such that a weld zone 46 is formed, which forms the formation of annular notches in the transition from an annular groove in the Connection nipple reduced. If an annular groove is milled only after the connection nipple 12 has been welded to the distributor tube 10, if the welding zone 46 is sufficiently wide, the connection nipple 12 can be milled to such an extent that the undercut in the transition from the annular bead 48 (FIG. 5) of the connection nipple to the distributor tube 10 is largely or completely removed is eliminated.

At the connection nipple 12, a branch line (not shown) can be secured in a conventional manner by means of a union nut, which presses the branch line sealingly against the conical region 30 or the mouth 18. For a connection with a Branch line, the connection nipple 12 can be designed in a variety of ways and is not limited to the training with an external thread.

LIST OF REFERENCE NUMBERS

10 manifold

12 connection nipples

14 longitudinal bore

16 cross bore

18 estuary

20 connection recess

22 inside wall

24 bottom wall

26 ring groove

28 outer wall

30 area

32 cylindrical area

34 area

36 external thread

38 area

40 area

42 area

44 contact area

46 welding zone

48 ring bead

50 inner ring groove

Claims

claims

1. A fuel rail assembly with a manifold (10) and at least one connection nipple (12) for connecting a branch line to a through the wall of the manifold (10) leading transverse bore (16), characterized in that an outer side of the connecting nipple (12) via a Outside of the connecting nipple at least partially surrounding, in the outside of the manifold (10) molded annular groove (26) merges into the outside of the manifold.

2. A fuel rail assembly according to claim 1, characterized in that the inside of the connecting nipple (12) in a in the outside of the manifold (10) formed inner annular groove (50) merges, the mouth (18) of the transverse bore (16) in the outside surrounds the manifold by a distance.

3. The fuel distributor assembly according to claim 1 or 2, characterized in that the annular groove (26) in longitudinal section through the distributor tube (10) has an approximately kreisbogensegment- shaped cross-section.

4. Fuel distributor assembly according to one of claims 1 to 3, characterized in that the connection nipple (12) is formed integrally with the distributor tube (10).

5. Fuel distributor assembly according to one of claims 1 to 3, characterized in that around the outside mouth (18) of the transverse bore (16) around a Anschlußaus- recess (20) with a circumferential inner wall (22), a circumferential bottom wall (24) and an outer wall (28) present at least in the apex region of the outer side of the distributor tube (10) is formed, and an end face of the connecting nipple (12) facing the distributor tube is welded to the bottom wall in such a way that the outer side of the connecting nipple is inserted into the bottom wall via the annular groove the outer wall of the connection recess merges.

6. The fuel rail assembly according to claim 5, characterized in that the annular groove (26) extends the outer wall (28) of the connection recess (20) towards the inside of the distributor tube (10) below the level of the bottom wall (24) and that the Ring groove (26) in the radial direction to the transverse bore (16) on the inside on the outside of the weld (46) of the connecting nipple (12) with the bottom wall (24) ends.

7. fuel distributor assembly according to claim 5 or 6, characterized in that the connection nipple (12) from the inner wall (22) and the outer wall (28) of the connection recess (20) is spaced.

8. fuel distributor assembly according to one of claims 5 to 7, characterized in that the end face of the connecting nipple (12) with the bottom wall (24) of the connection recess (20) is welded by capacitor discharge.

9. manifold (10) for producing a fuel rail assembly with the manifold (10) and at least one welded to the manifold connecting nipple (12) for connecting a branch line, which fuel distributor assembly through the wall of the manifold (10) leading transverse bore (16) and a around the outer mouth (18) and transverse bore (16) arranged around connecting recess (20) with a circumferential inner wall (22), a circumferential bottom wall (24) and at least in the apex region of the outer side of the manifold (10) existing outer wall (28) in which an end face of the connection nipple (12) facing the distributor tube (10) is welded to the bottom wall (24) of the connection recess and the outside of the connection nipple passes over an annular groove (26) into the bottom wall (24) or the outer wall of the connection recess, which Distributor tube (10) before its welding with the connection nipple (12) with the Ri ngnut (26) is formed whose width measured in extension of the bottom wall (24) is about half the distance between the inner wall (22) and the outer wall (28) of the connection recess (20) and the inner side at the transition to the bottom wall (24) is inclined towards the bottom wall.

10. Distributor tube according to claim 9, characterized in that the depth of the annular groove (26) is smaller than half their width.

11. connection nipple (12) for producing a fuel distributor assembly with a manifold (10) and at least one welded to the manifold connection nipples pel (12) for connecting a branch line, which fuel distributor subassembly has a transverse bore (16) passing through the wall of the distributor tube (10) and a connection recess (20) arranged around the outside mouth (18) of the transverse bore (16) and having a circumferential inner wall (16). 22), a circumferential bottom wall (24) and an at least in the apex region of the outside of the manifold (10) existing outer wall (28), wherein the distributor tube (10) facing end face of the connection nipple (12) with the bottom wall (24) of the connection recess (20) is welded and the outer side of the connecting nipple passes over an annular groove (26) in the bottom wall (24) or the outer wall (28) of the connection recess, which annular groove (26) before welding the distributor tube (10) to the connection nipple (12 ) is formed in the connection recess (20) and a width of the annular groove (26) measured in extension of the bottom wall (24) is approximately half the distance s between the inner wall (22) and the outer wall (28) of the connection recess (20) and whose inner side is inclined at the transition to the bottom wall to the bottom wall, and further wherein the radial outer side of the connection nipple (12) and the radial inner side of the connection nipple ( 12) over tapered conical surfaces (34, 42) in an annular contact surface (44) pass, which is engageable with the bottom wall (24) can be brought.

12. Connection nipple according to claim 11, wherein the connection nipple (12) at its contact surface (44) facing the end region with a protruding from its outer side annular bead (48) is formed.

13. A method for producing a fuel distributor assembly comprising a distributor tube (10) and at least one connection nipple (12) for connecting a branch line to a transverse bore (16) passing through the wall of the distributor tube (10), which method comprises the following steps:

Manufacture of a one-piece assembly of manifold and nipple (12), molding a the outer side of the connecting nipple (12) at least partially surrounding annular groove in the outside of the manifold so that the outside of the nipple (12) via the annular groove (26) in the outside of the Manifold tube passes.

14. A method of manufacturing a fuel rail assembly having a manifold and at least one nipple (12) welded to the manifold for connection to End of a branch line, which fuel rail assembly through the wall of the manifold (10) leading transverse bore (16) and around the outside mouth (18) of the transverse bore (16) around arranged connection recess (20) having a circumferential inner wall (22), a circumferential Bottom wall (24) and an outer wall (28) present at least in the apex region of the outside of the distributor tube (10), which method comprises the following steps:

Forming the connection recess (20) such that its outer wall (28) via an annular groove (26) merges into the bottom wall (24) and subsequently

Inserting the connection nipple (12) into the connection recess and welding an end face of the connection nipple (12) facing the distributor tube (10) to a region of the bottom wall (24) of the connection recess (20) located radially inside the annular groove (26).

15. A method for producing a fuel rail assembly comprising a manifold and at least one connection nipple (12) welded to the manifold for connection to a branch pipe, which fuel rail assembly passes through the wall of the fuel rail

Distributor tube (10) leading transverse bore (16) and one around the outside mouth (18) of the transverse bore (16) arranged around the connection recess (20) having a circumferential

Inner wall (22), a circumferential bottom wall (24) and an outer wall (28) present at least in the apex region of the outside of the distributor tube (10), which method comprises the following steps:

Inserting the connection nipple (12) into the connection recess (20),

Welding of the distributor tube (10) facing end face of the connection nipple

(12) with the bottom wall (24) of the connection recess (20) and subsequently

Forming an annular groove (26) at least partially surrounding the connecting nipple, the radially inner region of which is connected to a welding zone (46) between the connecting nipple (12) and the

Bottom wall (24) adjacent or emanating from this.