CHARGING DEVICE

Abstract

The invention relates to a charging device (1), more preferably an exhaust gas turbocharger for a motor vehicle, with a turbine housing (3) adjoining a bearing housing (2), in which a variable turbine geometry (4) is arranged. It is substantial for the invention that a one-piece disc spring (5) of plate with a bent over edge region is provided, wherein the bent over edge region forms a spring leg (6), while a protective leg (7) is designed as heat protection for the spring leg (6), that the spring leg (6) on the one hand supports itself on the bearing housing (2) and on the other hand on the variable turbine geometry (4), preloading the latter against the turbine housing (3).

Description

The present invention relates to a charging device, more preferably an exhaust gas turbocharger for a motor vehicle, according to the preamble of claim 1.

In modern motor vehicles, so-called exhaust gas turbochargers with variable turbine geometries are increasingly employed, wherein the power outputs and the response characteristics can be adapted to different operating conditions of the combustion engine. The variable turbine geometries employed here mostly have rotatable guide blades and are usually preloaded by means of a spring device, more preferably by means of a disc spring, relative to a bearing and/or a turbine housing of the charging device. Because of the high temperatures when operating the charging device a decline of the spring force of the disc spring can occur however, as a result of which the operation of the charging device can be impaired.

From EP 1 672 177 A1 a generic exhaust gas turbocharger with a cartridge for the variable turbine geometry arranged in a turbine housing is known. Here, the variable turbine geometry is fixed by means of a Woodruff key which is constructed of at least two material layers. The one material layer is intended to generate the axial preload force while the other material layer merely serves as a heat shield for the resilient material layer. The manufacture of such a disc spring however is involved and consequently expensive.

The present invention deals with the problem of stating an improved embodiment for a charging device of the generic type which is more preferably producible more cost effectively. According to the invention, this problem is solved through the subject of the independent Claim 1. Advantageous embodiments are the subject of the dependent claims.

The invention is based on the general idea of providing a charging device with a variable turbine geometry with a one-piece disc spring with a bent over edge region embodied of plate, wherein the bent over edge region forms a spring leg, while the protective leg of the disc spring which compared with the spring leg according to FIG. 1 is radially orientated, is embodied as heat shield for the spring leg. Here, the spring leg on the one hand supports itself on a bearing housing of the charging device and on the other hand on the variable turbine geometry, preloading the latter against the turbine housing. It is obviously also conceivable that the disc spring preloads the variable turbine geometry against a guide blade cage or on a cover disc. Through the one-piece disc spring embodied of plate, which by means of a later forming operation receives its bent over edge region, a temperature-insensitive, that is extremely resistant disc spring can be created which maintains its spring force even under extended, high thermal load. The term “bent over” is to be merely understood purely exemplarily for different forming methods, so that a flanged-over or offset edge region can also be included under the invention. The disc spring produced in this manner is of a simple construction and shaped by means of a simple forming method and consequently producible extremely cost-effectively. In addition, the protective leg of the disc spring brings about protection against excessively high temperatures, as a result of which the disc spring in turn can be improved with respect to its performance and its lifespan. In contrast with the prior art, the disc spring according to the invention is not produced of two different materials, but merely of a single material.

With an advantageous further development of the solution according to the invention the bent over edge region of the disc spring is embodied interrupted in circumferential direction and comprises a plurality of straps. The interruptions provided in circumferential direction can be produced simply by means of a suitable stamping method with disc spring initially still flat, wherein the stamped-out straps can simply be bent over in a later forming step. Obviously it is also conceivable as an alternative that the bent over edge region is embodied closed in circumferential direction, although this results in higher internal stresses caused by the forming process, the spring force of the disc spring according to the invention can however be increased on the whole. Irrespective of whether the bent over edge region in circumferential direction is embodied closed or interrupted, both alternatives can however be produced simply and thus cost-effectively from a production point of view.

Further important features and advantages of the invention are obtained from the subclaims, from the drawings and from the corresponding 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 are not only usable in the respective combinations stated but also in other combinations or by themselves, without leaving the scope of the present invention.

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

Here it shows, in each case schematically,

FIG. 1 a sectional view through a charging device according to the invention in the region of a variable turbine geometry,

FIGS. 2,3 differently configured disc springs,

FIG. 4 a sectional view through a disc spring according to FIG. 2,

FIG. 5 a view as in FIG. 1, however with another embodiment,

FIGS. 6,7 differently configured disc springs,

FIG. 8 a view as in FIG. 1, however with a further embodiment,

FIGS. 9,10 differently configured disc springs.

According to FIG. 1, a charging device 1 according to the invention, which more preferably can be designed as an exhaust gas turbocharger for a motor vehicle, comprises a turbine housing 3 adjoining a bearing housing 2, in which a variable turbine geometry 4 is arranged. According to the invention, a one-piece disc spring 5, that is formed of a single continuous material, of plate with an edge region bent over on the outside is provided, wherein the bent over edge region forms a spring leg 6, while the compared with the spring leg 6 radial protective leg 7 serves as heat shield for the spring leg 6. Obviously the protective leg 7 can also be embodied bent the other way round, that is inside. Here, the spring leg 6 on the one hand supports itself on the bearing housing 2 and on the other hand on the variable turbine geometry 4, preloading the latter against the turbine housing 3.

In principle the disc spring 5 can have different configurations as is for example shown according to FIGS. 2 and 3. With the disc spring 5 according to FIG. 2 the bent over edge region is closed in circumferential direction, while this bent over edge region according to FIG. 3 is designed interrupted in circumferential direction and comprises a plurality of straps 8. The term “bent over” obviously is not only intended to mean a bending method, so that the edge region for example can also be offset or flanged or folded.

The straps 8 shown according to FIG. 3 are usually stamped out when stamping out the basic shape of the disc spring 5 and subsequently bent over. In contrast with this, with a disc spring 5 according to FIG. 2, the edge region is bent over completely, when not inconsiderable stresses occur during the forming operation. However, these stresses can subsequently contribute to an increase in the strength of the disc spring 5.

Further considering FIG. 1 it is possible to see that both the spring leg 6 as well as the protective leg 7 support themselves on the bearing housing 2 of the charging device 1 while a blade bearing race 9 of the variable turbine geometry 4 comprises a suitable contact surface 10, more preferably a radial stage, which the disc spring 5 abuts on the other end.

A particular advantage with the disc spring 5 according to the invention is that on the one hand it can be produced simply and cost-effectively and on the other hand its springy effect is retained in the long term since the protective leg 7 acts as heat shield for the spring leg 6. Because of this, the temperature in the disc spring 5, more preferably at the contact point of the disc spring 5 with the blade bearing race 9 can be lowered, which increases both its spring force as well as its lifespan. Generally, the disc spring 5 according to the invention can be employed for both diesel and spark ignition engines.

As on the contact surface 10 of the blade bearing race 9, contact surfaces 10′ and 10″ can also be provided on the bearing housing 2, on which the spring leg 6 and the protective leg 7 rest respectively in order to achieve a certain sealing effect. Through the preload force generated by means of the disc spring 5 the variable turbine geometry 4 is pressed in the direction of the turbine housing 3 and thus held in position. Obviously a disc spring 5 of this type can generally be also employed for additional fixing purposes with a charging device 1, more preferably for example for fixing a bearing disc or a variable turbine geometry.

According to FIGS. 5 and 8, the charging device 1 according to the invention likewise comprises a turbine housing 3 adjoining the bearing housing 2, in which the variable turbine geometry 4 is arranged. According to the invention, a one-piece disc spring 5 that is formed of a single continuous material of plate with an edge region (see FIG. 5) bent over on the inside is provided, which bent over edge region the spring leg 6 adjoins, while the compared with the spring leg 6 radial protective leg 7 serves as heat shield for the spring leg 6. Here the spring leg 6 supports itself on the bearing housing 2 on the one hand and on the variable turbine geometry 4 on the other hand, preloading the latter against the turbine housing 3.

In principle the disc spring 5 can have different configurations as is shown for example in FIGS. 6 and 7. With the disc spring 5 according to FIG. 6 the bent over edge region is closed in circumferential direction, while this bent over edge region according to FIG. 7 is designed interrupted in circumferential direction and comprises a plurality of straps 8. This applies in the same manner also to the disc springs 5 shown according to FIGS. 9 and 10.

Further considering FIG. 5 one can see that both the spring leg 6 as well as the protective leg 7 support themselves on the blade bearing race 9 of the charging device 1, specifically in the region of contact surfaces 10a and 10b, which more preferably are embodied in the manner of a radial stage.

Here, the protective leg 7 of the disc spring 5 generally contacts the bearing housing 2 if a sealing function is desired, but need not necessarily so if for example no sealing is required.

Claims

1. An exhaust gas turbocharger device comprising: a turbine housing adjoining a bearing housing, in which a variable turbine geometry is arranged, such that a one-piece disc spring includes at least one bent over edge region, wherein the bent over edge region forms a spring leg, and a protective leg as heat protection for the spring leg, such that the spring leg supports itself on at least one of the bearing housing and on the variable turbine geometry, preloading the latter against at least one of the turbine housing, a cover disc and a cage.

2. The exhaust gas turbocharger device according to claim 1, wherein the bent over edge region is closed in a circumferential direction.

3. The exhaust gas turbocharger device according to claim 1, wherein the bent over edge region is interrupted and comprises a plurality of straps in a circumferential direction.

4. The charging device according to claim 1, wherein the bent over edge region is arranged in at least one of outside and inside.

5. The charging device according to claim 1, wherein the bent over edge region is produced through at least one of flanging and folding.

6. The charging device according to claim 1, wherein the variable turbine geometry includes a blade bearing race including a contact surface which the disc spring abuts.

7. The charging device according to claim 1, wherein at least one of the spring leg and the protective leg supports itself on the bearing housing of the charging device.

8. The charging device according to claim 1, wherein the disc spring is a heat shield.

9. The charging device according to claim 2, wherein the bent over edge region is arranged in at least one of outside and inside.

10. The charging device according to claim 2, wherein the bent over edge region is produced through at least one of flanging and folding.

11. The charging device according to claim 2, wherein the variable turbine geometry includes a blade bearing race including a contact surface, having a radial stage which the disc spring abuts.

12. The charging device according to claim 2, wherein at least one of the spring leg and the protective leg supports itself on the bearing housing of the charging device.

13. The charging device according to claim 2, wherein the disc spring is a heat shield.

14. The charging device according to claim 3, wherein the bent over edge region is arranged in at least one of outside and inside.

15. The charging device according to claim 3, wherein the bent over edge region is produced through at least one of flanging and folding.

16. The charging device according to claim 3, wherein the variable turbine geometry includes a blade bearing race including a contact surface, more preferably a radial stage which the disc spring abuts.

17. The charging device according to claim 3, wherein at least one of the spring leg and the protective leg supports itself on the bearing housing of the charging device.

18. The charging device according to claim 3, wherein the disc spring is a heat shield.

19. The charging device according to claim 4, wherein the bent over edge region is produced through at least one of flanging and folding.

20. The charging device according to claim 4, wherein the variable turbine geometry includes a blade bearing race including a contact surface, having a radial stage which the disc spring abuts.