Turbine housing and associated exhaust-gas turbocharger

Abstract

A turbine housing of an exhaust-gas turbocharger may include at least two spiral-shaped exhaust-gas channels separated from one another via a partition. The at least two channels may be delimited radially to the outside by the turbine housing and radially to the inside by at least two spiral tongues. A first spiral tongue may be associated with one of the channels and a second spiral tongue may be associated with the other of the channels. The at least two spiral tongues may extend in opposite directions away from the partition in a direction towards the turbine housing. According to an example, the at least two spiral tongues may be configured such that, under an increasing thermomechanical loading, the first spiral tongue fails before the second spiral tongue.

Claims

1. A turbine housing of an exhaust-gas turbocharger, comprising: at least two spiral-shaped exhaust-gas channels separated from one another via a partition, the at least two spiral-shaped exhaust-gas channels being delimited radially to the outside by an inner surface of the turbine housing and radially to the inside by at least two spiral tongues, wherein the at least two spiral tongues are respectively associated with one of the at least two spiral-shaped exhaust-gas channels and extend in opposite directions away from the partition, wherein the at least two spiral tongues include a first spiral tongue and a second spiral tongue, wherein the first spiral tongue extends between the partition and an exhaust pipe-side region of the turbine housing, and the second spiral tongue extends between the partition and a bearing housing-side region of the turbine housing, and wherein the at least two spiral tongues are configured such that, under an increasing thermomechanical loading, the first spiral tongue fails before the second spiral tongue; wherein the first spiral tongue has a smaller wall thickness and a lower strength than the second spiral tongue; and wherein one of the first and second spiral tongues include a first concave surface facing toward a respective spiral-shaped exhaust-gas channel.

2. The turbine housing according to claim 1, wherein the first spiral tongue has a wall thickness of approximately 50% to approximately 90% of a wall thickness of the second spiral tongue, wherein the first spiral tongue has a lower strength than the second spiral tongue.

3. The turbine housing according to claim 1, wherein at least the turbine housing and the partition are formed in one piece.

4. The turbine housing according to claim 1, wherein the turbine housing, the partition and the at least two spiral tongues are formed in one piece, and wherein the first spiral tongue has at least one of a smaller wall thickness and a lower strength than the second spiral tongue.

5. The turbine housing according to claim 1, wherein the turbine housing is a cast part.

6. The turbine housing according to claim 1, wherein the at least two exhaust-gas channels are arranged axially adjacent to one another.

7. The turbine housing according to claim 1, wherein one of the first and second spiral tongues includes the first concave surface facing toward its respective spiral-shaped exhaust-gas channel, and the other of the first and second spiral tongues includes a second concave surface facing toward its respective spiral-shaped exhaust-gas channel.

8. The turbine housing according to claim 7, wherein one of the first and second spiral tongues includes a third concave surface opposing the first concave surface and facing away from the respective spiral-shaped exhaust-gas channel, and the other of the first and second spiral tongues includes a fourth concave surface opposing the second concave surface and facing away from the respective spiral-shaped exhaust-gas channel.

9. The turbine housing according to claim 1, wherein the housing is a twin-scroll turbine housing.

10. An exhaust-gas turbocharger for a motor vehicle, comprising: a turbine housing, the turbine housing including: at least two spiral-shaped exhaust-gas channels separated from one another via a partition, the at least two spiral-shaped exhaust-gas channels being delimited radially to the outside by the turbine housing and radially to the inside by at least two spiral tongues, wherein the at least two spiral tongues include a first spiral tongue associated with one of the at least two spiral-shaped exhaust-gas channels and a second spiral tongue associated with the other of the at least two spiral-shaped exhaust-gas channels, and wherein the at least two spiral tongues extend in opposite directions from the partition in a direction towards the turbine housing; wherein the first spiral tongue extends between the partition and an exhaust pipe-side region of the turbine housing, and the second spiral tongue extends between the partition and a bearing housing-side region of the turbine housing; and wherein the at least two spiral tongues are configured such that, under an increasing thermomechanical loading, the first spiral tongue fails before the second spiral tongue; wherein the first spiral tongue has a smaller wall thickness and a lower strength than the second spiral tongue; and wherein at least one of the first and second spiral tongues include a first concave surface facing toward a respective spiral-shaped exhaust-gas channel.

11. The exhaust-gas turbocharger according to claim 10, wherein the first spiral tongue has a wall thickness of approximately 50% to approximately 90% of a wall thickness of the second spiral tongue.

12. The exhaust-gas turbocharger according to claim 11, wherein the turbine housing, the partition and the at least two spiral tongues are configured in one piece.

13. The exhaust-gas turbocharger according to claim 10, wherein at least the turbine housing and the partition are configured in one piece.

14. The exhaust-gas turbocharger according to claim 10, wherein the turbine housing, the partition and the at least two spiral tongues are configured in one piece.

15. The exhaust-gas turbocharger according to claim 10, wherein the turbine housing is a cast part.

16. The exhaust-gas turbocharger according to claim 15, wherein the cast part is a cast steel component.

17. The exhaust-gas turbocharger according to claim 10, wherein the at least two exhaust-gas channels are arranged axially adjacent to one another, wherein the turbine housing and the partition are configured in one piece.

18. The exhaust-gas turbocharger according to claim 10, wherein one of the first and second spiral tongues includes the first concave surface facing toward its respective spiral-shaped exhaust-gas channel, and the other of the first and second spiral tongues includes a second concave surface facing toward its respective spiral-shaped exhaust-gas channel.

19. The exhaust-gas turbocharger according to claim 18, wherein one of the first and second spiral tongues includes a third concave surface opposing the first concave surface and facing away from the respective spiral-shaped exhaust-gas channel, and the other of the first and second spiral tongues includes a fourth concave surface opposing the second concave surface and facing away from the respective spiral-shaped exhaust-gas channel.

20. The exhaust-gas turbocharger according to claim 10, wherein the two spiral-shaped exhaust-gas channels are in a twin-scroll turbine arrangement.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the drawings, in each case schematically:

(2) FIG. 1 is a sectional illustration through a turbine housing according to the invention of an exhaust-gas turbocharger,

(3) FIG. 2 is likewise a sectional illustration through the turbine housing according to the invention, but in a different section plane.

DETAILED DESCRIPTION

(4) Correspondingly to FIGS. 1 and 2, a turbine housing 1 according to the invention has an exhaust-gas turbocharger 2 (not otherwise shown) and has two spiral-shaped exhaust-gas channels 3, 4 which are separated from one another by a partition 5 and which are delimited radially to the outside by the turbine housing 1 and radially to the inside by in each case one spiral tongue 6, 7. Here, the two spiral tongues 6, 7 extend in opposite directions away from the partition 5 in the direction of the turbine housing 1. Here, FIG. 1 shows only an upper half of the turbine housing 1, wherein the exhaust-gas channel 4 is arranged adjacent to a bearing housing 8 and the exhaust-gas channel 3 is arranged adjacent to an exhaust pipe 9. Here, during operation of the exhaust-gas turbocharger 2, it is the second spiral tongue 7 in particular that is exposed to high thermomechanical loading and is thus at risk of forming cracks, wherein, in the event of a crack forming in the second spiral tongue 7, crack propagation through the turbine housing 1, which is relatively thin at this location, as far as the outside could occur and thus lead to undesired leakage of hot gas. Here, according to the invention, the two spiral tongues 6, 7 are designed such that, under increasing thermomechanical loading, the first spiral tongue 6 fails first. This may be realized for example by way of different strengths, wherein the strength of the first spiral tongue 6 is lower than the strength of the second spiral tongue 7, such that, in the event of a critical thermomechanical load being reached, it is always the case that the first spiral tongue 6 cracks first, and thus the second spiral tongue 7 can be relieved of load.

(5) The first spiral tongue 6 thus has a type of predetermined breaking point or is formed as a sacrificial tongue and, in the event of a critical temperature loading being reached, prevents the formation of through-running cracks in the second spiral tongue 7 and the associated crack propagation through the turbine housing 1, which must imperatively be avoided.

(6) In order to realize the different strengths of the two spiral tongues 6, 7 in a simple manner, the two spiral tongues 6, 7 have different wall thicknesses d.sub.1, d.sub.2, as can also be clearly seen from FIG. 2. For example, the first spiral tongue 6 has a wall thickness d.sub.1 which corresponds to only approximately 50 to 90% of the wall thickness d.sub.2 of the second spiral tongue 7, such that, in the event of a critical mechanical loading being reached, it is always the case that the first spiral tongue 6 cracks first. It would self-evidently also be possible in the same way for a predetermined breaking point to actually be provided, for example in the form of a cross-sectional narrowing, in the region of the first spiral tongue 6.

(7) In general, the turbine housing 1 and the partition 5 may be formed in one piece, wherein furthermore, it is self-evidently possible for the two spiral tongues 6, 7 to also be formed in one piece with the turbine housing 1. For this purpose, it is for example possible for the turbine housing 1 to be produced as a metallic cast component, for example from cast aluminium. The two exhaust-gas channels 3, 4 are in this case situated axially adjacent to one another in relation to an axis of rotation 10.

(8) In general, in the case of the turbine housing 1 according to the invention, the risk of a hot-gas leakage crack exists only in the event of cracking of the second spiral tongue 7; by contrast, in the case of the first spiral tongue 6, such a hot-gas leakage crack is not possible owing to the geometric situation of the twin-scroll spiral under the prevailing loading conditions. For this reason, according to the invention, the first spiral tongue 6 is designed to be weaker than the second spiral tongue 7, such that the first spiral tongue 6 can be used as a sacrificial tongue and thus for relieving the second spiral tongue 7, which is at risk of forming through-running cracks, of thermomechanical load. In the event of a superficial crack or a through-running crack forming in the first spiral tongue 6, the second spiral tongue 7 is still far from reaching its strength limit, wherein, in the event of a through-running crack forming in the first spiral tongue 6, the second spiral tongue 7 is simultaneously mechanically relieved of load, and a risk of hot-gas leakage cracks in the region of the two spiral tongues 6, 7 can be reduced. In this way, it is possible in particular to realize a longer service life of the turbine housing 1.

(9) By way of the embodiment of the first spiral tongue 6 with reduced material usage and simultaneously relatively low weight, it is possible not only for the life expectancy and the thermomechanical load capacity of the turbine housing 1 according to the invention to be increased, but furthermore also for material and weight savings to be achieved, because in particular, in order to prevent thermomechanical cracks in the second spiral tongue 7, the latter no longer has to be mechanically reinforced. Furthermore, it is possible to realize a reduction in the required thermomechanical optimization loops and thus also a reduction in simulation and design outlay. It is likewise possible to reduce a number of tests for component strength certification on the engine or on a hot-gas test stand. The turbine housing 1 according to the invention may in this case be realized in simple form through modification of a corresponding casting tool. It is furthermore highly advantageous that the turbine housing 1 according to the invention can also be operated at higher gas temperatures than similar turbine housings hitherto known from the prior art.