US20200254515A1

US20200254515A1 - Cast Component Having a Cast-In Pipe and Production Method

Info

Publication number: US20200254515A1
Application number: US16/651,606
Authority: US
Inventors: Jan Göbel
Original assignee: ZF Friedrichshafen AG
Current assignee: ZF Friedrichshafen AG
Priority date: 2017-09-29
Filing date: 2018-08-14
Publication date: 2020-08-13
Also published as: CN111148585A; HUE057191T2; EP3687714B1; CN111148585B; DE102017217387A1; EP3687714A1; WO2019063184A1

Abstract

A metallic cast component (100), which is a housing component, includes a cast body (110) and at least one pipe (120) cored in the cast body (110) and through which a medium (F) is flowable. The pipe (120) includes a pipe connection (121, 122) formed at or in a surface of the cast body (110) on at least one of pipe end of the pipe (120). The pipe (120) also includes, at the pipe end, an enclosing bush (130) embedded in the cast body (110). The enclosing bush (130) effectuating a seal between the pipe end and the cast body (110). A method for manufacturing such a cast component (100) is also provided.

Description

CROSS-REFERENCE TO RELATED APPLICATION

The present application is related and has right of priority to PCT Application No. PCT/EP2018/071962 filed on Aug. 14, 2018 and to German Patent Application No. 10 2017 217 387.4 filed on Sep. 29, 2017, both of which are incorporated by reference in their entirety for all purposes.

FIELD OF THE INVENTION

The invention relates generally to a cast component that includes at least one cored pipe, through which a medium can flow. The invention further relates generally to a method for manufacturing this cast component.

BACKGROUND

DE 10 2012 223 156 A1 describes a housing (exhaust gas valve housing), which includes at least one heating or cooling duct, which is a pipe enclosed by the housing. The ends of the pipe are designed for the connection of a line. The housing is made of die cast aluminum and the pipe is made of aluminum or copper. In order to manufacture the housing, the preformed pipe is placed, in the manner of a core, into a mold for the housing and, thereafter, is encapsulated during the casting of the housing.
Gaps and/or air gaps can form between the cored pipe and the enclosing casting material during the casting or even in the course of the subsequent use. The gaps and/or air gaps are due, inter alia, to an unfavorable material fusion between the casting material and the pipe material and/or to different thermal expansions. Such gaps can extend along the pipe up to the component surface, where the connections and/or pipe connections are also frequently located. At the pipe connections, the medium to be conducted through the pipe can then undesirably enter such gaps and escape elsewhere.

SUMMARY OF THE INVENTION

According to various example aspects of the invention, at least one disadvantage associated with the prior art is to be avoided or at least diminished.
The metallic cast component according to example aspects of the invention includes a metallic cast body (body) produced via casting and at least one pipe cored in the cast body. A medium can flow through the pipe, wherein the pipe includes, on at least one of the pipe ends of the pipe, a pipe connection formed at or in the cast body surface. Moreover, the pipe also includes, at least on this pipe end, a bush surrounding the pipe end. The bush is (at least partially) embedded in the cast body, in particular in the cast body surface. With the aid of the bush, a seal is achieved and/or effectuated between the particular pipe end and the cast body.
The pipe is, in particular, a metal pipe, which can be made of an aluminum alloy or of a steel alloy. The pipe can also include a coating (for example, a zinc plating) or casing.
The bush is preferably a metal bush, which is connected, in particular integrally bonded, to the enclosing casting material of the cast body. The casting material is preferably an aluminum alloy, i.e., the cast body is made of an aluminum casting alloy and/or an aluminum die casting alloy. The metal bush is made, in particular, of a zinc alloy. During the die casting, an integral bond can form between the aluminum alloy of the cast body and the zinc alloy of the bush to be embedded.
The metal bush, in particular zinc bush, can be designed as a separate bush and attached at the particular pipe end. The metal bush is, in particular, a component manufactured by machining, in particular a turned part. The metal bush can be soldered, welded, and/or pressed together with the particular pipe end. A bush and, in particular, a metal bush can also be formed, however, via material deposition onto the particular pipe end, for example, via deposition welding, plasma spraying, or the like.
With the aid of the bush, which is attached at the pipe end and is embedded in the cast body and/or the cast body surface, a gap seal at the pipe connection is achieved. On the one hand, the (inner) connection between the bush and the pipe end is tight. On the other hand, the bush is embedded into the metallic casting material in such a way that this (outer) connection is also tight. In particular, there is a micro-form-locking and/or integral bond between the embedded bush and the enclosing casting material. In example aspects, the invention therefore does not attempt to prevent a gap formation by optimizing the connection between the casting material and the pipe, but rather seals off any gaps between the casting material and the pipe at the cast body surface with the aid of a bush. As a result, at the connection of the pipe, the medium, which is to be conducted through the pipe, cannot penetrate between the casting material and the pipe, nor can the medium be pressed out from between the casting material and the pipe. If necessary, the sealing complexity at the pipe connections can also be reduced.
The bush or the metal bush can have a radial thickness (wall thickness) of three millimeters (3 mm) to ten millimeters (10 mm) and, in particular, of four millimeters (4 mm) to six millimeters (6 mm), wherein the bush can also be thinner or thicker. As compared to the pipe wall thickness, the bush preferably has thicker walls. Moreover, the bush or the metal bush can have an axial length of five millimeters (5 mm) to twenty millimeters (20 mm) and, preferably, of ten millimeters (10 mm) to fifteen millimeters (15 mm).
The method according to example aspects of the invention for manufacturing a cast component, which includes at least one cast body and at least one pipe—through which a medium can flow—cored in the cast body, includes:

- providing the pipe, which is, in particular, a metal pipe;
- installing at least one bush on at least one of the pipe ends of the pipe, in particular via soldering-on, welding-on, and/or pressing-on a metal bush or via direct material deposition onto the pipe end;
- placing the pipe into a mold, in particular a pressure die, and casting, in particular die casting, the cast component, wherein the pipe is encapsulated in molten metal and, in the process, the bush is also embedded into the produced cast body, in particular into the cast body surface;
- removing the cast component from the mold once the molten metal has solidified;
- producing at least one pipe connection via a refinishing of the particular pipe end and/or the particular bush, which is understood to be, in particular, a machining operation in which, for example, a connecting face, at least one mounting hole, and/or a connecting thread can be formed.

The pipe can be shaped before or after the installation of the at least one bush, so that the pipe is placed into the mold, having been 3-dimensionally preformed. Preferably, the pipe is a metal pipe, which is placed into the mold in the cold condition (i.e., having, for example, room temperature) and is subsequently encapsulated. A complex preheating is therefore not provided.
At least one bush can be designed to include a cover, which closes and/or seals off the particular pipe end during casting, wherein the cover is removed during the refinishing.
The cast component designed and/or manufactured according to example aspects of the invention is preferably a housing component and, in particular, a transmission housing component for a motor vehicle transmission.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained in greater detail in the following with reference to the drawings. Regardless of certain combinations of features, the features shown in the figures of the drawings and/or explained in the following can be general features of the invention and can appropriately refine the invention.

FIG. 1 shows a diagrammatic sectioning of a first example design option of the invention.

FIG. 2 shows a diagrammatic sectioning of a second example design option of the invention including pipe connections, which have not yet been completed.

DETAILED DESCRIPTION

Reference will now be made to embodiments of the invention, one or more examples of which are shown in the drawings. Each embodiment is provided by way of explanation of the invention, and not as a limitation of the invention. For example, features illustrated or described as part of one embodiment can be combined with another embodiment to yield still another embodiment. It is intended that the present invention include these and other modifications and variations to the embodiments described herein.
FIG. 1 shows a section of a pressure die casting 100, which is a transmission housing component. The cast component 100 includes a cast body 110 manufactured with the aid of aluminum die casting, and a steel pipe 120 cored therein, which is designed as a U-bend, by way of example. The steel pipe 120 has, for example, a diameter of eight millimeters (8 mm) to twenty millimeters (20 mm) and a pipe wall thickness of approximately two millimeters (2 mm). Both pipe ends of the steel pipe 120 are formed including pipe connections 121 and 122 at the cast body surface. A feed line and drain line for a medium F (for example, oil, water, or air), which is to be conducted through the pipe 120, can be connected at the pipe connections 121 and 122. The left pipe connection 121 is designed as a planar connecting face and the right pipe connection 122 is designed as a neck. The cast component or the housing component 100 is manufactured via die casting, as explained above, for the purpose of which the steel pipe 120 is placed into the pressure die and encapsulated. After the casting, the pipe connections 121 and 122 are completed with the aid of mechanical refinishing.
As explained above, gaps or air gaps S can form between the casting material M and the steel pipe 120. Without the measure according to example aspects of the invention, at the pipe connections 121 and 122, the medium F, which is to be conducted through the pipe 120, could undesirably enter such a gap S. An optimal seal at the transfer points or pipe connections 121 and 122 is not always possible or is highly complex. The medium F that has entered a gap S can then escape somewhere else (for example, reaching the outer surface through blow holes and porosities), which is perceived as a housing leak or leakage.
In order to prevent this, the pipe ends of the steel pipe 120 are each provided with a soldered-on, welded-on, and/or pressed-on zinc bush 130, which surround the pipe ends in a collar- or ring-like manner and are embedded at the cast body surface into the casting material M. (The term “component surface” or “cast body surface” encompasses not only the outer surface, but also the inwardly adjacent zone or layer, so that, for example, reference can also be made to an outer layer or peripheral zone.) A material fusion (integral bond) arises between the zinc bushes 130 and the aluminum casting material M during the die casting. A direct integral bond can not be established between the aluminum casting material M and the steel pipe 120, however, or can only be established with great effort. The soldering, welding, and/or pressing of the zinc bushes 130 with the steel pipe 120 and the material fusion of the zinc bushes 130 with the casting material M form a reliable seal, so that the medium F cannot enter a gap S.
FIG. 2 shows another example design option. The condition after the cast component or the housing component 100 has been removed from the pressure die is represented. The pipe connections 121 and 122 have not yet been completed. The zinc bushes 130 are formed as one piece with a cover 131, with the aid of which the pipe ends of the steel pipe 120 are closed or sealed off during die casting. The zinc bushes 130 are therefore initially designed as caps. A pipe overhang (see right pipe connection 122 in FIG. 1), which is also provided for attaching a plug, or the like, and/or for fixing the steel pipe 120 in the cavity of the pressure die, can be omitted. Therefore, the subsequent cutting-off of this pipe overhang can also be omitted, if necessary.
In the design option shown in FIG. 2, the pipe ends of the steel pipe 120 are even arranged to be recessed, for example, i.e., the front ends of the steel pipe 120 do not extend up to the outer surface of the cast body 110. During the mechanical refinishing of the pipe connections 121 and 122, wherein the sections or areas labeled with “A” are cut off or removed, tools provided exclusively for the machining of aluminum can therefore be utilized.
Modifications and variations can be made to the embodiments illustrated or described herein without departing from the scope and spirit of the invention as set forth in the appended claims. In the claims, reference characters corresponding to elements recited in the detailed description and the drawings may be recited. Such reference characters are enclosed within parentheses and are provided as an aid for reference to example embodiments described in the detailed description and the drawings. Such reference characters are provided for convenience only and have no effect on the scope of the claims. In particular, such reference characters are not intended to limit the claims to the particular example embodiments described in the detailed description and the drawings.

REFERENCE SIGNS

- 100 cast component (housing component)
- 110 cast body
- 120 pipe
- 121 pipe connection
- 122 pipe connection
- 130 bush
- 131 cover
- A section
- F medium
- M casting material
- S gap

Claims

1-10: (canceled)

11. A metallic cast component (100), comprising:

a cast body (110); and

at least one pipe (120) cast in the cast body (11) and through which a medium (F) is flowable, the pipe (120) comprises a pipe connection (121, 122) formed at or in a surface of the cast body (110) on at least one of pipe end of the pipe (120), c

wherein the pipe (120) also comprises an enclosing bush (130) at the pipe end, the enclosing bush (130) embedded in the cast body (110) and effectuating a seal between the pipe end and the cast body (110).

12. The cast component (100) of claim 11, wherein the pipe (120) is a metal pipe.

13. The cast component (100) of claim 11, wherein the bush (130) is a metal bush integrally bonded with an enclosing casting material (M) of the cast body (110).

14. The cast component (100) of claim 13, wherein the casting material (M) is an aluminum alloy and the metal bush (130) is made of a zinc alloy.

15. The cast component (100) of claim 11, wherein the bush (130) has a radial thickness of no less than three millimeters and no greater than then millimeters.

16. The cast component (100) of claim 11, wherein the bush (130) has an axial length of no less than ten millimeters and no greater than fifteen millimeters.

17. The cast component (100) of claim 11, wherein the cast body (110) is a transmission housing component.

18. A method for manufacturing a cast component (100), which comprises a cast body (110) and a pipe (120) cast in the cast body (110) and through which a medium (F) is flowable, the method comprising:

installing at least one bush (130) on at least one pipe end of the pipe (120);

placing the pipe (120) into a mold and casting the cast component (100), wherein the pipe (120) is encapsulated in molten metal and the bush (130) is embedded into the cast body (110) during the casting of the cast component (100);

removing the cast component (100) from the mold once the molten metal has solidified; and

producing at least one pipe connection (121, 122) by refinishing one or more of the at least one pipe end and the at least one bush (130).

19. The method of claim 18, wherein the pipe (120) is a metal pipe, and the metal pipe is placed into the mold and is encapsulated in a cold condition.

20. The method of claim 18, wherein each of the at least one bush (130) comprises a cover (131) that closes a respective one of the at least one pipe end during casting and is removed during the refinishing.