SCREWABLE BEARING HOUSING COVER FOR A SUPERCHARGING DEVICE

Abstract

A bearing housing may have a bearing housing cover formed of metal. A first thread may be arranged on the bearing housing cover and a second thread may be arranged on the bearing housing and designed complementarily to the first thread so that the bearing housing cover may be screwed on and fixed on the bearing housing through a rotational movement.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to German Patent Application 10 2011 075 517.9 filed on May 9, 2011, German Patent Application 20 2010 017 275.6 filed on Jun. 29, 2010, and International Patent Application PCT/EP2011/060794 filed on Jun. 28, 2011, all of which are hereby incorporated by reference in their entirety.

TECHNICAL FIELD

The present invention relates to a bearing housing cover for a bearing housing of a charging device, in particular for an exhaust gas turbocharger of a motor vehicle. Furthermore, an exhaust gas turbocharger having such a bearing housing is likewise subject of the invention.

BACKGROUND

From WO 2010/002717 A2 a generic bearing housing for an exhaust gas turbocharger is known. On the compressor side, the bearing housing comprises an opening which is closed off with a bearing housing cover. Thus, through the bearing housing cover, the compressor housing interior can be divided from or closed off against the bearing housing interior in a gas-tight manner. The bearing housing cover can be fixed to the bearing housing with a bayonet closure. The bearing housing cover is designed furthermore in such a manner that in installation position it serves as mounting for the shaft sealing rings or piston rings.

Usually, a bearing housing cover is currently embodied with a circumferential annular groove for a sealing element such as for example an O-ring. Thus, the manufacture of the bearing housing cover requires a plurality of machining operations and among other things can only be accomplished with elaborate design and in an expensive manner for this reason.

SUMMARY

The present invention now deals with the problem of stating an improved or at least an alternative embodiment for a bearing housing cover and a bearing housing which is characterized in particular by a simple assembly and a reduced parts variety.

According to the invention, this problem is solved through the subjects of the independent claims. Advantageous embodiments are subject of the dependent claims.

In the case of a bearing housing of a charging device, the present invention is based on the general idea of fixing a bearing housing cover closing off the bearing housing to the actual bearing housing via a screw connection, wherein the bearing housing cover itself forms a screw element. The term screw connection thus does not mean additional screws via which the bearing housing cover is securely screwed to the bearing housing, but the bearing housing cover itself is designed as screw and can be securely screwed and thus fixed to the bearing housing through a rotational movement. To this end, the bearing housing cover according to the invention comprises a first thread, whereas the bearing housing according to the invention comprises a second thread designed complementarily thereto, so that the bearing housing cover can be screwed to the bearing housing through a simple rotational movement. Because of this, the omission of additional fastening means, such as for example screws, is possible, likewise the omission of additional sealing means such as for example O-ring seals. Through the omission of these additional parts, the parts variety can be substantially reduced and the assembly additionally simplified.

With an advantageous further development of the solution according to the invention, the first thread is an external thread and the second thread an internal thread designed complementarily thereto, wherein the external thread can be additionally designed in a self-locking manner. With this embodiment, a simple screwing-in of the bearing housing cover into the internal thread on the bearing housing is made possible, wherein for the simplified screwing-in for example a sliding agent can be additionally and purely optionally used. In order to achieve as tight as possible an arrangement of the bearing housing cover on the bearing housing, a seal can be provided on the face end of the bearing housing cover, in particular a seal sprayed on by means of a screen printing method, via which the bearing housing cover tightly bears against a corresponding bearing contour of the bearing housing. Through this sprayed-on and therefore easy-to-manufacture seal together with the self-locking external thread, a simple and at the same time reliably tight closure of the bearing housing through the bearing housing cover can be achieved.

With an advantageous further development of the solution according to the invention, the bearing housing cover is produced by means of a forming method, in particular by means of forging or cold extrusion. Such extrusion methods usually belong to the pressure forming methods, with which the material to be formed is made to flow under the effect of a high pressure. The forming usually takes place at room temperature, which in this case it is called cold extrusion. Components produced in such a manner and in the present case bearing housing covers are characterized by a particularly high dimensional accuracy and a high surface quality. A particular advantage hereby is that such cold-extruded components can be produced particularly cost-effectively yet in a high quality. During forging, by contrast, the work piece to be produced is pressure-formed between two dies without cutting, namely usually above or below the re-crystallisation temperature, which is why the words hot or cold forming are used. Advantages in particular are a low material loss in contrast with cutting machining and because of this an economical manufacturability.

Practically, the bearing housing cover is designed of steel and comprises a corrosion protection in the form of a nitrocarburizing or a burnishing. The nitrocarburizing is a gas nitriting connected with carbon absorption, as a result of which surfaces are usually hardened. The burnishing, by contrast, serves for forming a protective layer of ferrous surfaces in order to reduce the corrosion hazard by doing so. Both methods, i.e. both the nitrocarburizing as well as the burnishing substantially increase the corrosion resistance, by which in particular high-quality materials of steel can be finished.

Further important features and advantages of the invention are obtained from the subclaims, from the drawings and from the associated Figure description by means of the drawings.

It is to be understood that the features mentioned above and still to be explained in the following cannot only be used in the respective combination stated but also in other combinations or by themselves without leaving the scope of the present invention.

Preferred exemplary embodiment of the invention are shown in the drawings and are explained in more detail in the following description, wherein same reference characters relate to same or similar or functionally same components.

BRIEF DESCRIPTION OF THE DRAWINGS

It shows, in each case schematically:

FIG. 1 a sectional representation through a bearing housing according to the invention with a bearing housing cover screwed into said bearing housing,

FIG. 2 a view of a possible embodiment of the bearing housing cover.

DETAILED DESCRIPTION

According to FIG. 1, a bearing housing 1 of a charging device which is not otherwise shown, for example of an exhaust gas turbocharger of a motor vehicle, comprises a bearing housing cover 2 formed of metal. In order to fasten the bearing housing cover 2 to the bearing housing 1 in a preferably simple manner and because of this also seal in particular the bearing housing 1 in axial direction, a first thread 3 is provided on the bearing housing cover 2 and a second thread 4 formed complementarily thereto is provided on the bearing housing 1 according to the invention, so that the bearing housing cover 2 can be screwed to the bearing housing 1 through a simple rotational movement. The first thread 3 on the bearing housing cover 2 in this case is designed as external thread, whereas the second thread 4 on the bearing housing 1 is configured as internal thread designed complementarily thereto, or vice versa. In addition, the external thread and/or the internal thread, i.e. the first thread 3 and/or the second thread 4 can be designed in a self-locking manner, as a result of which an unintentional loosening of the bearing housing cover 2 from the bearing housing 1 can be avoided or at least rendered more difficult.

The bearing housing cover 2 in this case is designed of aluminium, in particular of die-cast aluminium or steel, wherein in the latter case the bearing housing cover 2 can additionally have a corrosion protection in the form of a nitrocarburizing or a burnishing. In order to be able to manufacture the bearing housing cover 2 as cost-effectively as possible yet of a high quality, it can be preferentially produced by means of a forming method, in particular by means of forging or cold extruding.

For sealing the bearing housing cover 2 against the bearing housing 1, a seal 5 can be additionally provided, which for example can be sprayed onto an end face of the bearing housing cover 2 by means of a screen printing method. Additionally or alternatively, such a seal 5 can obviously be attached or sprayed on also in a corresponding location of the bearing housing 1. Obviously, the use of conventional O-ring seals is also conceivable.

In order to be able to easily screw the bearing housing cover 2 into the bearing housing 1, the bearing housing cover 2 can comprise a driving profile 6, for example a Torx or an Allen (see in particular FIG. 2).

With the screwable bearing housing cover 2 according to the invention, the parts variety in particular can be reduced, since for example separate fastening elements such as for example screws can be omitted. At the same time, the assembly of the bearing housing cover 2 to the bearing housing 1 is simplified. The screwing on/screwing in of the bearing housing cover 2 on/into the bearing housing 1 can be carried out by means of a suitable turning tool such as for example a socket or a Torx wrench, with which the bearing housing cover 2 is screwed into the bearing housing 1 against an axial bearing, to which for example the seal 5 is also attached. In order to be able to simplify the screwing-in of the bearing housing cover 2, the bearing housing cover 2 can be coated with a suitable sliding agent in particular in the region of its first thread 3 and/or the bearing housing 1 in the region of its second thread 4. Because of this, not only the assembly process, i.e. for example the screwing-in can be simplified but in addition to this, thread damages during the screwing together, additionally avoided.

With the bearing housing cover 2 according to the invention and the associated bearing housing 1 its assembly on the bearing housing 1 can thus be simplified and in addition the parts variety reduced, as a result of which in particular storage and logistic costs can be reduced.

Claims

1. A bearing housing of a charging device, comprising: a bearing housing cover formed of metal, a first thread arranged on the bearing housing cover, a second thread arranged on the bearing housing and designed complementarily to the first thread so that the bearing housing cover can be screwed on and fixed on the bearing housing through a rotational movement.

2. The bearing housing according to claim 1, wherein the first thread is an external thread and the second thread is an internal thread complementarily formed thereto.

3. The bearing housing according to claim 1, wherein at least the first thread is of a self-locking design.

4. The bearing housing according to claim 1, wherein the bearing housing cover is formed of aluminium.

5. The bearing housing according to claim 1, wherein the bearing housing cover has a driving profile.

6. The bearing housing according to claim 1, wherein the bearing housing cover is formed of steel and has a corrosion protection in the form of at least one of a nitrocarburizing and a burnishing.

7. The bearing housing according to claim 1, wherein the bearing housing cover is produced by at least one of forging and cold extruding.

8. The bearing housing according to claim 1, wherein the bearing housing cover comprises a seal.

9. (canceled)

10. An exhaust gas turbocharger, comprising: a bearing housing having a bearing housing cover formed of metal,

a first thread arranged on the bearing housing cover, and

a second thread arranged on the bearing housing and designed complementarily to the first thread so that the bearing housing cover can be screwed on and fixed on the bearing housing through a rotational movement.

11. The turbocharger according to claim 10, wherein the first thread is an external thread and the second thread is an internal thread complementarily formed thereto.

12. The turbocharger according to claim 10, wherein at least the first thread is of a self-locking design.

13. The turbocharger according to claim 10, wherein the bearing housing cover is formed of aluminium.

14. The turbocharger according to claim 10, wherein the bearing housing cover has a driving profile.

15. The turbocharger according to claim 10, wherein the bearing housing cover is formed of steel and has a corrosion protection in the form of at least one of a nitrocarburizing and a burnishing.

16. The turbocharger according to claim 10, wherein the bearing housing cover is produced by at least one of forging and cold extruding.

17. The turbocharger according to claim 10, wherein the bearing housing cover comprises a seal.

18. The bearing housing according to claim 8, wherein the bearing housing cover comprises a seal moulded on by a screen printing method.

19. The bearing housing according to claim 4, wherein the bearing housing cover is formed of at least one of die-cast aluminium and steel.

20. The bearing housing according to claim 5, wherein the driving profile is at least one of a Torx and an Allen.