Pipe Section of a Common Rail Line and Methods for Manufacturing Same

Abstract

The invention relates to a pipe section 1 of a common rail line 2 that is provided for the high-pressure injection of a fluid, wherein the pipe section 1 has at least a first pipe 3 and an adapter 4; wherein the first pipe 3 has a wall 6 and extends at least along an axial direction 7; wherein the wall 6 has an inner circumferential surface 8 and an outer circumferential surface 9 and encloses a first line 10; wherein the adapter 4 has a connector piece 11 and a second pipe 12; wherein the connector piece 11 extends annularly around the first pipe 3 and is situated on the outer circumferential surface 9; wherein a second line 13 that is formed by the second pipe 12 is fluidically connected to the first line 10 via a first opening 14 in the first pipe 3 and a second opening 15 in the connector piece 11; wherein at least the adapter 4 is manufactured by means of a metal powder injection molding process.

The invention further relates to two methods for manufacturing a pipe section 1.

Claims

1. A pipe section of a common rail line that is provided for the high-pressure injection of a fluid, wherein the pipe section comprises at least a first pipe and an adapter, wherein the first pipe has a wall and extends at least along an axial direction; wherein the wall has an inner circumferential surface and an outer circumferential surface and encloses a first line; wherein the adapter has a connector piece and a second pipe; wherein the connector piece extends annularly around the first pipe and is situated on the outer circumferential surface; wherein a second line that is formed by the second pipe is fluidically connected to the first line via a first opening in the first pipe and a second opening in the connector piece; wherein at least the adapter is manufactured by a metal powder injection molding process.

2. The pipe section according to claim 1, wherein the connector piece of the adapter forms mat least a force-fit connection with the outer circumferential surface of the first pipe.

3. The pipe section according to claim 2, wherein the adapter and the first pipe, in addition to the force-fit connection, are joined together at least by a form-fit connection.

4. The pipe section according to claim 3, wherein the form-fit connection is formed by a projection on the adapter which encloses the second opening and extends into the first opening.

5. The pipe section according to claim 1, wherein the adapter and the first pipe are connected to one another in a fluid-tight manner via the outer circumferential surface, the fluid-tight seal being ensured solely via the force-fit connection.

6. The pipe section according to claim 1, wherein the adapter and the first pipe are connected to one another in a fluid-tight manner via the outer circumferential surface, wherein the fluid-tight seal is ensured via the at least force-fit connection and also via an additional seal.

7. The pipe section according to claim 1, wherein the first pipe and the adapter are manufactured as an assembly by a metal powder injection molding process, wherein the first pipe and the adapter are integrally joined together.

8. A method for manufacturing a pipe section of a common rail line that is provided for the high-pressure injection of a fluid, at least comprising the following steps: a) Providing a first pipe, wherein the first pipe has a wall and extends at least along an axial direction; wherein the wall has an inner circumferential surface and an outer circumferential surface and encloses a first line; b) Manufacturing at least one one-piece adapter by means of a metal powder injection molding process; wherein the adapter has a sleeve-like connector piece for accommodating the first pipe, and has a second pipe; c) Pushing the sleeve-like connector piece onto the first pipe so that the connector piece extends annularly around the first pipe, and forming an assembly; d) Sintering the assembly; wherein the adapter with the sleeve-like connector piece is shrunk onto the outer circumferential surface of the first pipe, thus forming an at least force-fit connection.

9. The method according to claim 8, wherein prior to step c) the first pipe has at least a first opening in the wall, and wherein in step b) the connector piece is provided with a second opening; wherein in step d) a second line that is formed by the second pipe is fluidically connected to the first line via the first opening in the first pipe and the second opening in the connector piece.

10. The method according to claim 8, wherein the adapter and the first pipe, in addition to the force-fit connection, are connected to one another at least by a form-fit connection, wherein the form-fit connection is formed by a projection on the adapter that encloses the second opening; wherein in step c) the connector piece is situated on the first pipe in such a way that the projection (extends into the first opening; wherein in step c) the projection is used for aligning the adapter with the first pipe.

11. The method according to claim 8, wherein prior to step d) a seal is applied in the area between the connector piece and the outer circumferential surface, the seal ensuring a fluid-tight seal of the connection between the adapter and the first pipe via the outer circumferential surface.

12. A method for manufacturing a pipe section of a common rail line that is provided for the high-pressure injection of a fluid, comprising the following steps: a) Manufacturing the pipe section, having at least a first pipe and an adapter as a one-piece assembly, by a metal powder injection molding process; wherein the first pipe has a wall and extends at least along an axial direction; wherein the wall has an inner circumferential surface and an outer circumferential surface and encloses a first line; wherein the adapter has a connector piece and a second pipe; wherein the connector piece extends annularly around the first pipe; wherein a second line that is formed by the second pipe is fluidically connected to the first line via a first opening in the first pipe and a second opening in the connector piece; b) sintering the assembly.

Description

[0038] The invention and the technical field are explained in greater detail below with reference to the figures. It is pointed out that the invention is not to be construed as being limited by the illustrated exemplary embodiments. In particular, unless explicitly stated otherwise, it is also possible to extract partial aspects of the information shown in the figures and combine them with other components and findings from the present description and/or figures. Identical objects are denoted by the same reference numerals, so that explanations concerning other figures may possibly be supplementally used. The figures schematically show the following:

[0039] FIG. 1: shows a first embodiment variant of a pipe section in a cross-sectional side view; and

[0040] FIG. 2: shows a second embodiment variant of a pipe section in a cross-sectional side view.

[0041] FIG. 1 shows a first embodiment variant of a pipe section 1 in a cross-sectional side view. The pipe section 1 has a first pipe 3 and an adapter 4. The first pipe 3 has a wall 6 and extends at least along an axial direction 7. The wall 6 has an inner circumferential surface 8 and an outer circumferential surface 9 and encloses a first line 10. The adapter 4 has a connector piece 11 and a second pipe 12, wherein the connector piece 11 extends annularly around the first pipe 3 and is situated on the outer circumferential surface 9. A second line 13 formed by the second pipe 12 is fluidically connected to the first line 10 via a first opening 14 in the first pipe 3 and a second opening 15 in the connector piece 11. The adapter 4 is manufactured by means of a metal powder injection molding process.

[0042] FIG. 1 also illustrates the method for manufacturing the pipe section 1 of a common rail line 2. The first pipe 3 is provided according to step a). A one-piece adapter 4 is manufactured by means of a metal powder injection molding process and provided according to step b) (see the left illustration of the adapter 4). In step c) the adapter 4 with the sleeve-like connector piece 11 is pushed onto the first pipe 3 so that the connector piece 11 extends annularly around the first pipe 3 and forms an assembly 19 (see the left illustration in FIG. 1). The assembly 19 is sintered in step d), wherein the adapter 4 with the sleeve-like connector piece 11 is shrunk onto the outer circumferential surface 9 of the first pipe 3, thus forming a force-fit connection 5 (and optionally also an integral connection) (see the right illustration in FIG. 1).

[0043] Prior to step c), the first pipe 3 has a first opening 14 in the wall 6, wherein in step d) a second line 13 that is formed by the second pipe 12 is fluidically connected to the first line 10 via the first opening 14 in the first pipe 3 and the second opening 15 in the connector piece 11.

[0044] The adapter 4 and the first pipe 3 are connected to one another in a fluid-tight manner via the outer circumferential surface 9, the fluid-tight seal being ensured solely via the force-fit (and optionally also integral) connection 5 between the first pipe 3 and the connector piece 11. This ensures that a fluid conveyed through the common rail line can flow into the second pipe 12 only via the first opening 14 and the second opening 15, thus preventing passage of the fluid via the force-fit (and optionally also integral) connection 5 (see the right illustration in FIG. 1).

[0045] FIG. 1 may additionally be used to illustrate the pipe section 1 that is manufactured in one piece. The right illustration of the pipe section 1 in FIG. 1 shows that the first pipe 3 and the adapter 4 are manufactured as a (joint, one-piece) assembly by means of a metal powder injection molding process, wherein the first pipe 3 and the adapter 4 are integrally joined together. The integral connection is formed due to the fact that during the injection molding, the first pipe 3 and the adapter 4 are already manufactured as a one-piece, integrally joined assembly 19. The indicated separating lines between the adapter 4 and the first pipe 3 illustrate only the individually described components (adapter 4 and first pipe 3), which in fact have a joint one-piece design without a noticeable separation in the structure.

[0046] FIG. 2 shows a second embodiment variant of a pipe section 1 in a cross-sectional side view. Reference is made to the discussion for FIG. 1. In contrast to FIG. 1, in this case the adapter 4 and the first pipe 3, in addition to the force-fit (and optionally also integral) connection 5, are joined together at least by a form-fit connection 16. The form-fit connection 16 is used solely for aligning the components (first pipe 3, adapter 4) with one another during the manufacturing process. The required strength of the connection for the sintered assembly 19, made up of the first pipe 3 and the adapter 4, is ensured solely by the force-fit (and optionally also integral) connection 5.

[0047] The form-fit connection 16 is formed by a projection 17 on the adapter 4 that encloses the second opening 15 and extends into the first opening 14. The adapter 4 may be pushed onto the first pipe 3 prior to the sintering (see the left illustration of the adapter 4). The adapter 4 may be positioned in a predetermined position with respect to the first pipe 3 via the projection 17 and the first opening 14. For this purpose, there is play 20 (a clearance fit) between the projection 17 and the first opening 14 so that precise positioning may be ensured.

[0048] The second embodiment variant additionally differs by the following feature: In this case the adapter 4 and the first pipe 3 are joined together in a fluid-tight manner via the outer circumferential surface 9, the fluid-tight seal being ensured via the force-fit (and optionally also integral) connection 5, as well as via an additional sealing means 18.

[0049] A brazing material that is applied in the area of the force-fit connection 5 prior to the sintering is used as an additional sealing means 18 (see the left illustration of the pipe section 1). By use of the brazing material, only the sealing effect is ensured. Here as well, the majority of the required strength of the connection between the adapter 4 and the first pipe 3 is ensured via the force-fit (and optionally also integral) connection 5.

LIST OF REFERENCE NUMERALS

[0050] 1 pipe section

[0051] 2 common rail line

[0052] 3 first pipe

[0053] 4 adapter

[0054] 5 force-fit connection

[0055] 6 wall

[0056] 7 axial direction

[0057] 8 inner circumferential surface

[0058] 9 outer circumferential surface

[0059] 10 first line

[0060] 11 connector piece

[0061] 12 second pipe

[0062] 13 second line

[0063] 14 first opening

[0064] 15 second opening

[0065] 16 form-fit connection

[0066] 17 projection

[0067] 18 sealing means

[0068] 19 assembly

[0069] 20 play