Nozzle rings for radial turbines, exhaust turbines, turbochargers

Abstract

The present invention relates to a nozzle ring (10) for a radial turbine. The nozzle ring (10) comprises a first ring element (11), a second ring element (12) and a number of guide vanes (13) arranged between the first ring element (11) and the second ring element (12). The second ring element (12) comprises an end region (12E) which extends exclusively radially inward and has a convex curvature (141) on the side surface (121) facing the first ring element (11). The present invention also relates to an exhaust turbine and a turbocharger.

Description

[Technical field]

[0001] The present invention relates to the field of exhaust turbines, in particular turbochargers with radial turbines. In particular, the invention relates to a nozzle ring for a radial turbine. [Background technology]

[0002] To improve the performance of internal combustion engines, turbochargers are nowadays standardized, which include a turbine in the exhaust system of the internal combustion engine and a compressor upstream of the internal combustion engine. In this configuration, the exhaust gases of the internal combustion engine are decompressed in the turbine. The work obtained is transferred via a shaft to the compressor, which compresses the air that is fed to the internal combustion engine. By using the energy of the exhaust gases to compress the air that is fed to the combustion process of the internal combustion engine, the efficiency level of the combustion process and the internal combustion engine can be optimized.

[0003] The kinetic and thermal energy of the exhaust gases is used to drive the rotor of the turbocharger. To ensure safe operation, the exhaust gas flow must be directed in a targeted manner to the turbine shaft. For this purpose and to thermodynamically adapt the turbocharger for different applications, if there is a radial turbine stage at the outlet of the flow duct, a nozzle ring is installed upstream of the turbine shaft. The exhaust gases are fed through a nozzle ring of the turbine, which is coupled upstream of the turbine. The vane arrangement of the nozzle ring influences the characteristics of the turbocharger. Different nozzle rings are used depending on the application.

[0004] The turbine or gas inlet housing is a cast part that is conventionally manufactured in a sand casting process. In this process, the flow duct inside the housing is represented by what is called a core in the mold. This core is connected to the outer contour of the mold. This connection is called the core gap. In this component, the core gap is at the position where the nozzle ring is located in the turbocharger. For technical reasons, the core gap must have a minimum cross section to ensure sufficient stability of the connection with the outer mold.

[0005] It has been found that for small turbine blades (trims) in the area between the nozzle ring and the turbine wheel (core gap area of ​​the mould) a flow contour is required which cannot be produced from the available blanks, as the blanks do not provide enough material. For casting reasons, it is not possible to adapt the blanks, since such an adaptation would reduce the core gap to a cross section which could no longer be used to produce the housing. Summary of the Invention [Problem to be solved by the invention]

[0006] The object of the present invention is to provide a solution to the above problems. [Means for solving the problem]

[0007] In order to achieve the above object, there is provided a nozzle ring and an exhaust turbine as set forth in the independent claims.Furthermore, there is provided a turbocharger including an exhaust turbine according to the embodiments described herein.Further aspects, advantages and features of the invention can be found in the dependent claims, the detailed description and the accompanying drawings.

[0008] According to one aspect of the invention, a nozzle ring for a radial turbine is provided, the nozzle ring comprising a first annular element, a second annular element and a number of guide vanes disposed between the first and second annular elements, the second annular element comprising an end region extending exclusively radially inwardly, the end region having a convex curvature on the side facing the first annular element.

[0009] Advantageously, a nozzle ring is thus provided, by which the above-mentioned manufacturing-related drawbacks in the casting process of the housing can be at least partially or completely eliminated. In particular, the nozzle ring advantageously substitutes or bridges the missing material from the turbine housing as a result of manufacturing-related limitations. In particular, the second annular element of the nozzle ring is advantageously configured in such a way that the drawbacks and limitations associated with casting for manufacturing radial turbines with small turbine blades can be eliminated and improvements in terms of flow can be achieved.

[0010] In a second aspect, the invention relates to an exhaust turbine, in particular a radial turbine. The exhaust turbine comprises a turbine housing with a gas inlet housing, a radial gas inlet duct arranged in the gas inlet housing and a nozzle ring arranged in the radial gas inlet duct. The nozzle ring comprises a first annular element, a second annular element and a number of guide vanes arranged between the first and second annular elements. The second annular element comprises an end region extending exclusively radially inwards, which region has a convex curvature on the side facing the first annular element. In particular, the convex curvature extends to the radially inner end of the second annular element. An axial gap exists between the side of the second annular element facing away from the first annular element and the opposite side of the gas inlet housing.

[0011] Advantageously, an improved exhaust turbine is provided as a result with respect to the prior art, in particular an exhaust turbine is provided whereby the above-mentioned manufacturing related disadvantages in the housing casting process can be at least partially or completely eliminated.

[0012] A third aspect of the present invention relates to a turbocharger comprising an exhaust turbine according to embodiments described herein, advantageously providing an improved turbocharger with respect to the prior art.

[0013] The invention will now be described with reference to exemplary embodiments shown in the drawings, from which further advantages and modifications will become apparent. [Brief description of the drawings]

[0014] [Figure 1] 1 is a schematic cross-sectional view of a nozzle ring according to an embodiment described herein. [Diagram 2] FIG. 13 is a schematic cross-sectional view of a nozzle ring according to a further embodiment described herein. [Diagram 3] 1 is a schematic cross-sectional view of an exhaust turbine including a nozzle ring according to an embodiment described herein. [Figure 4] 4 illustrates an enlarged area of ​​FIG. 3, with a nozzle ring shown installed in accordance with embodiments described herein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Various embodiments are described in detail below, one or more examples of which are shown in each drawing. It should be understood that each example is used for illustrative purposes and is not limiting. For example, features shown or described as part of an embodiment can be used on or in combination with any other embodiment to obtain a further embodiment. The present disclosure is intended to cover such modifications and variations.

[0016] In the following description of the drawings, the same reference numbers relate to the same or similar components. Only the differences related to the individual embodiments are generally described. Unless otherwise indicated, the description of one part or aspect in one embodiment can be applied to the corresponding part or aspect in another embodiment.

[0017] 1 to 4, a nozzle ring 10 for a radial turbine according to an embodiment of the present disclosure will be described.

[0018] According to one embodiment, which can be combined with other embodiments described herein, the nozzle ring 10 comprises a first annular element 11, a second annular element 12 and a number of guide vanes 13, as exemplarily shown in FIG. 1. The guide vanes 13 are arranged between the first annular element 11 and the second annular element 12. Typically, a flow duct 17 is arranged between the first annular element 11 and the second annular element 12. In other words, the intermediate space between the first annular element 11 and the second annular element 12 provides the flow duct 17. The first annular element 11 typically defines the flow duct 17 on the bearing housing side. In FIG. 3, an exemplary embodiment of the nozzle ring 10 is shown when mounted, where a turbine housing 21 and a bearing housing 22 are shown. Typically, the second annular element 12 defines the flow duct 17 on the turbine housing side. The second annular element 12 comprises an end region 12E that extends exclusively radially inwards. The radial direction r and the axial direction x are indicated in figures 1 to 4 by corresponding arrows. As can be seen from the figures, the end region 12E, which extends exclusively radially inwards, is the end region on the outflow side. The flow direction S is indicated by arrows in figures 1 and 2. Typically, the length of the end region is not more than 50% of the total radial extent of the second annular element 12. The side surface 121 of the radially inner end region 12E of the second annular element 12, which faces the first annular element 11, has a convex curvature 141. It is clear from figures 1, 2 and 3 that the side surface 121 facing the first annular element 11 is typically the side surface of the nozzle ring 10, which defines the flow duct 17. In particular, the convex curvature 141 extends to the radially inner end of the second annular element 12. Typically, the convex curvature 141 is a continuous curvature.

[0019] Advantageously, a nozzle ring is thus provided, by which the above-mentioned casting-related drawbacks in the manufacture of turbine housings can be at least partially or completely eliminated. In particular, the nozzle ring embodiments described herein make it possible to substitute or bridge missing material from the turbine housing as a result of manufacturing-related limitations. In particular, advantageously, the second annular element of the nozzle ring is configured in such a way that the drawbacks and limitations associated with casting for the manufacture of radial turbines with small turbine blades can be eliminated and improvements in terms of flow can be achieved.

[0020] According to one embodiment, which can be combined with other embodiments described herein, the first annular element 11 is a support ring for the nozzle ring 10. The second annular element 12 can be a cover ring for the nozzle ring 10. In addition to defining the bearing housing side of the flow duct 17, the first annular element 11, in particular the support ring, can also be configured to provide a radial and / or axial positioning function for the nozzle ring. Furthermore, the first annular element 11, in particular the support ring, can be configured to provide a centering function in the turbine housing. Furthermore, the first annular element 11, in particular the support ring, can be configured to provide a contour that guides the flow in the direction of the turbine wheel after the flow around the guide vanes 13.

[0021] According to one embodiment, which can be combined with other embodiments described herein, the second annular element 12, in contrast to the first annular element 11, comprises an extension 14, which extends exclusively radially inwards, as exemplarily shown in FIG. 2. Material missing from the turbine housing due to manufacturing limitations can therefore advantageously be substituted or bridged by the extension 14. Advantageously, the extension 14 extends beyond the flow duct 17 of the nozzle ring 10. Furthermore, the extension 14 can advantageously be used to compensate for casting tolerances of the turbine housing in the transition area from the turbine housing to the nozzle ring. As exemplarily shown in FIG. 2, the extension 14 typically comprises a convex curvature 141. In particular, the convex curvature 141 extends to the radially inner end of the extension 14. An improved flow guidance in the direction of the turbine wheel can therefore be provided.

[0022] According to one embodiment, which can be combined with other embodiments described herein, as exemplarily shown in FIG. 2, the extension 14 extends beyond the radial extent R of the first annular element 11. 11 A length L that is at least 10% of V Alternatively, the length L V is the radial extent R of the first annular element 11 11 Illustratively, the length L V is the radial extent R of the first annular element 11 11 It may be at least 30% of the total.

[0023] According to an exemplary embodiment shown in Fig. 2, which can be combined with other embodiments described herein, the second annular element 12 further comprises an axial extension 15. The axial extension 15 is configured to be inserted into an axial receiving part 212 of a gas inlet housing 21E of the turbine housing 21, as exemplarily shown in Fig. 4. Typically, the axial extension 15 is arranged in the region of the second annular element 12 on the inlet side. According to one embodiment, not explicitly shown, the axial extension 15 can be arranged in the region of the annular element 12 on the outlet side.

[0024] According to one embodiment, which can be combined with other embodiments described herein, the axial extension 15 comprises a receiving portion 151 for the sealing element 16, as exemplarily shown in Figures 2 and 4. Typically, the receiving portion 151 for the sealing element 16 is arranged in a radially inner region of the axial extension 15. According to an embodiment, which is not explicitly shown, the receiving portion 151 for the sealing element 16 can be arranged in a radially outer region of the axial extension 15.

[0025] With reference to Figures 3 and 4, an exhaust turbine 20, in particular a radial turbine, according to an embodiment of the present disclosure is described. According to one embodiment, which can be combined with other embodiments described herein, the exhaust turbine 20 comprises a turbine housing 21 having a gas inlet housing 21E. The exhaust turbine can be understood as a turbine stage. A radial gas inlet duct 211 is arranged in the gas inlet housing 21E. The exhaust turbine is typically arranged on a shaft 24 having a central axis of rotation 25 attached to a bearing housing 22 and comprises a turbine wheel 23. Furthermore, the exhaust turbine 20 comprises a nozzle ring 10 arranged in the radial gas inlet duct 211. The nozzle ring 10 comprises a first annular element 11, a second annular element 12 and a number of guide vanes 13. The guide vanes 13 are arranged between the first annular element 11 and the second annular element 12. The second annular element 12 comprises an end region 12E extending exclusively radially inwards. The end region 12E has a convex curvature 141 on the side 121 facing the first annular element 11. In particular, the convex curvature 141 extends to the radially inner end of the second annular element 12. An axial gap S1 is located between the side 122 of the second annular element 12 facing away from the first annular element 11 and the opposing side 214 of the gas inlet housing 21E.

[0026] Advantageously, an improved exhaust turbine is provided as a result with respect to the prior art. In particular, a gas turbine is provided, whereby the above-mentioned manufacturing related drawbacks in the casting process of the housing can be at least partially or completely eliminated. In particular, an exhaust turbine is provided, whereby the drawbacks and limitations related to casting for manufacturing radial turbines with small turbine blades can be eliminated and flow related improvements can be achieved.

[0027] 2 and 4, in contrast to the first annular element 11, the second annular element 12 has an extension 14 that extends exclusively radially inwardly. Furthermore, the second annular element 12 may comprise an axial extension 15 that is at least partially arranged in the axial accommodation portion 212 of the gas inlet housing 21E, as exemplarily shown in FIG.

[0028] According to one embodiment, which can be combined with other embodiments described herein, the axial extension 15 comprises a receiving portion 151 for the sealing element 16, in which the sealing element 16 is arranged. Typically, the sealing element 16 provides a seal between the nozzle ring 10 and the gas inlet housing 21E. The sealing element 16 can be, for example, a sheet metal sealing ring.

[0029] According to one embodiment, which can be combined with other embodiments described herein, the axial accommodation 212 of the gas inlet housing 21E comprises a beveled portion 213 or a rounded portion, as exemplarily shown in Fig. 4. Typically, the beveled portion or the rounded portion is arranged in a radially inner region of the axial accommodation 212. Providing a beveled portion is convenient for inserting the axial extension 15 together with the sealing element 16 into the axial accommodation 212 of the gas inlet housing 21E.

[0030] According to one embodiment, which can be combined with other embodiments described in this specification, an axial gap S2 exists between the end face of the axial extension 15 and the axial receiving portion 212 of the gas inlet housing 21E.

[0031] According to one embodiment, which can be combined with other embodiments described in this specification, a radial gap S3 exists between the radially outer side of the axial extension 15 and the axial receiving portion 212 of the gas inlet housing 21E.

[0032] Providing the gaps S1, S2 and S3 described herein can be particularly advantageous for minimizing material stresses as a result of temperature related expansion of materials, particularly of the nozzle ring.

[0033] It is noted that the exhaust turbine 20 typically comprises a nozzle ring 10 according to one of the embodiments described herein. In light of the embodiments described herein, it is further noted that advantageously a turbocharger can be provided that includes an exhaust turbine according to an embodiment described herein. [Explanation of symbols]

[0034] 10 Nozzle ring 11 First annular element / support ring 12 Second annular element / covering 121 Side of the second annular element facing the first annular element 122 the side of the second annular element facing away from the first annular element 13 Guide vane 14 Radially inwardly extending extension 12E: the end region of the second annular element facing radially inward 141 Convex curved section 15 Axial extension 151 Seal element receiving part 16 Sealing elements 17 Flow Duct 20 Exhaust Turbine 21 Turbine housing 21E Gas Inlet Housing 211 Radial gas inlet duct 212 Axial receiving section in gas inlet housing for axial extension 213 Slope 214 a side of the gas inlet housing opposite a side of the second annular element facing away from the first annular element 22 Bearing housing 23 Turbine Wheel 24 Shaft 25 Central Rotation Axis S1 Axial clearance between the radial extension and the gas inlet housing S2 Axial clearance between the axial extension and the axial bearing of the gas inlet housing S3 Radial clearance between the axial extension and the axial bearing of the gas inlet housing r radial direction x-axis direction S Flow direction L V Length of radial extension of second annular element / covering R 11 Radial extent of the first annular element

Claims

1. A nozzle ring (10) for a radial turbine, the nozzle ring (10) comprising a first annular element (11), a second annular element (12) and a plurality of guide vanes (13) arranged between the first annular element (11) and the second annular element (12), the second annular element (12) comprising an end region (12E) extending exclusively radially inward, the end region (12E) having a convex curvature (141) on a side surface (121) facing the first annular element (11).

2. The nozzle ring (10) of claim 1, wherein the convex curvature (141) extends to a radially inner end of the second annular element (12).

3. 3. The nozzle ring (10) according to claim 1 or 2, wherein, in contrast to the first annular element (11), the second annular element (12) has an extension (14) which extends exclusively radially inwards.

4. The extension (14) has a length L V and the length L V is the radial extent R of the first annular element (11) 11 and in particular, the length L V is the radial extent R of the first annular element (11) 11 4. The nozzle ring (10) of claim 3, wherein the axial length of the nozzle ring is at least 30% of the axial length of the nozzle ring (10).

5. 5. The nozzle ring (10) according to claim 1, wherein the second annular element (12) further comprises an axial extension (15) for insertion into an axial receiving portion (212) of a gas inlet housing (21E) of a turbine housing (21).

6. 6. The nozzle ring (10) according to claim 5, wherein the axial extension (15) comprises a receiving portion (151) for a sealing element (16), in particular the receiving portion (151) for the sealing element (16) is arranged in a radially inner or outer region of the axial extension (15).

7. A turbine housing (21) having a gas inlet housing (21E); a radial gas inlet duct (211) arranged in said gas inlet housing (21E); A nozzle ring (10) according to any one of claims 1 to 6, arranged in the radial gas inlet duct (211); An exhaust turbine (20), in particular a radial turbine.

8. 8. The exhaust turbine (20) of claim 7, wherein an axial gap (S1) exists between a side (122) of the second annular element (12) facing away from the first annular element (11) and an opposing side (214) of the gas inlet housing (21E).

9. The exhaust turbine (20) of claim 7 or 8 in combination with claim 5, wherein the axial extension (15) is at least partially disposed within an axial accommodation portion (212) of the gas inlet housing (21E).

10. The exhaust turbine (20) according to any one of claims 7 to 9 in combination with claim 6, wherein a sealing element (16) is arranged in the receiving portion (151) for the sealing element (16) for providing a seal between the sealing ring (10) and the gas inlet housing (21E), in particular the sealing element (16) being a sheet metal sealing ring.

11. The exhaust turbine (20) according to claim 9 or 10, wherein the axial accommodation portion (212) of the gas inlet housing (21E) comprises a sloped portion (213) or a rounded portion.

12. The exhaust turbine (20) according to claim 11, wherein the inclined portion (213) or the rounded portion is arranged in a radially inner region of the axial accommodation portion (212).

13. 13. The exhaust turbine (20) according to any one of claims 9 to 12, wherein an axial gap (S2) exists between an end face of the axial extension portion (15) and the axial accommodation portion (212) of the gas inlet housing (21E).

14. 14. The exhaust turbine (20) according to any one of claims 9 to 13, wherein a radial gap (S3) exists between a radially outer side of the axial extension (15) and the axial accommodation portion (212) of the gas inlet housing (21E).

15. A turbocharger comprising an exhaust turbine (20) according to any one of claims 7 to 14.

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