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 to turbochargers equipped with radial turbines. More specifically, the present invention relates to a nozzle ring for a radial turbine.

Background Art

[0002] In order to improve the performance of internal combustion engines, recently, turbochargers equipped with turbines in the exhaust system of internal combustion engines and compressors upstream of the internal combustion engines have been standardly used. In this configuration, the exhaust gas of the internal combustion engine is decompressed by the turbine. The work obtained thereby is transmitted to the compressor via a shaft, and the compressor compresses the air supplied to the internal combustion engine. By using the energy of the exhaust gas to compress the air supplied to the combustion process of the internal combustion engine, the combustion process and the efficiency level of the internal combustion engine can be optimized.

[0003] The kinetic energy and thermal energy of the exhaust gas are used to drive the rotor of the turbocharger. To ensure safe operation, the exhaust gas flow needs to be directed to the turbine shaft as intended. For this purpose and to thermally adapt the turbocharger for various applications, when 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 gas is supplied through the nozzle ring of the turbine coupled upstream of the turbine. The vane arrangement of the nozzle ring affects the characteristics of the turbocharger. Various nozzle rings are used depending on the application.

[0004] The turbine or gas inlet housing is a cast component traditionally manufactured using a sand casting process. In this process, the flow duct inside the housing is represented by a core within the mold. This core is bonded to the outer contour of the mold. This bond is called the core clearance. In this component, the core clearance is located where the nozzle ring is positioned within the turbocharger. For technical reasons, the core clearance must have a minimum cross-section to ensure sufficient stability of the bond with the outer mold.

[0005] For small turbine blades (trims) in the region between the nozzle ring and the turbine wheel (the core clearance region of the mold), it has been found that a flow contour is required that cannot be manufactured from the available blank material because the blank material does not provide enough material. For casting reasons, it is impossible to fit the blank material, because such a fit would reduce the core clearance to a cross-section that can no longer be used for manufacturing the housing. [Overview of the Initiative] [Problems that the invention aims to solve]

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

[0007] To solve the above problems, a nozzle ring and exhaust turbine as described in an independent claim are provided. Furthermore, a turbocharger including an exhaust turbine according to an embodiment described herein is provided. Further aspects, advantages and features of the present invention can be found in the dependent claims, detailed description and accompanying drawings.

[0008] According to one aspect of the present invention, a nozzle ring for a radial turbine is provided. The nozzle ring comprises a first annular element, a second annular element, and a plurality of guide vanes disposed between the first and second annular elements. The second annular element has an end region that extends exclusively radially inward, and this region has a convex curved portion on the side surface facing the first annular element.

[0009] Advantageously, the nozzle ring is provided in this manner, thereby eliminating, at least partially or completely, the aforementioned manufacturing-related drawbacks in the casting process of the housing. More specifically, advantageously, the nozzle ring can substitute or bridge material missing from the turbine housing as a result of manufacturing-related limitations. More specifically, advantageously, the second annular element of the nozzle ring is configured to eliminate casting-related drawbacks and limitations for manufacturing radial turbines with small turbine blades and to achieve improvements in flow.

[0010] A second aspect of the present invention relates to an exhaust turbine, more particularly to a radial turbine. The exhaust turbine comprises a turbine housing having a gas inlet housing, a radial gas inlet duct disposed within the gas inlet housing, and a nozzle ring disposed within the radial gas inlet duct. The nozzle ring comprises a first annular element, a second annular element, and a plurality of guide vanes disposed between the first and second annular elements. The second annular element has an end region that extends exclusively radially inward, and this region has a convex curve on the side facing the first annular element. More specifically, the convex curve extends to the radially inward end of the second annular element. An axial clearance exists between the side of the second annular element facing away from the first annular element and the opposing side of the gas inlet housing.

[0011] Advantageously, an improved exhaust turbine is provided compared to the prior art. More specifically, an exhaust turbine is provided that can at least partially or completely eliminate the aforementioned manufacturing drawbacks in the housing casting process.

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

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

[0014] [Figure 1] This is a schematic cross-sectional view of a nozzle ring according to an embodiment described herein. [Figure 2] This is a schematic cross-sectional view of a nozzle ring according to further embodiments described herein. [Figure 3] This is a schematic cross-sectional view of an exhaust turbine including a nozzle ring according to an embodiment described herein. [Figure 4] Figure 3 shows an enlarged area, in which the nozzle ring is shown installed according to the embodiments described herein. [Modes for carrying out the invention]

[0015] Various embodiments are described in detail below, with one or more embodiments shown in each figure. It should be understood that each embodiment is for illustrative purposes only and is not restrictive. For example, features shown or described as part of an embodiment can be used on or in combination with any other embodiment to obtain further embodiments. This disclosure is intended to encompass such modifications and variations.

[0016] In the following description of the drawings, the same reference numerals relate to the same or similar components. Only differences relating to individual embodiments are described in general. Unless otherwise indicated, the description of one part or aspect in one embodiment may apply to the corresponding part or aspect in another embodiment.

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

[0018] According to one embodiment that 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 plurality of guide vanes 13, as illustrated in Figure 1. The guide vanes 13 are positioned between the first annular element 11 and the second annular element 12. Typically, a flow duct 17 is positioned 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. Figure 3 shows an exemplary embodiment of the nozzle ring 10 in installation, with the turbine housing 21 and the bearing housing 22 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 inward. The radial direction r and axial direction x are indicated by corresponding arrows in Figures 1 to 4. As can be seen from the drawings, the end region 12E, which extends exclusively radially inward, is the outflow end region. The flow direction S is indicated by arrows in Figures 1 and 2. Typically, the length of the end region is less than 50% of the entire radial range of the second annular element 12. The side surface 121 of the radially inward end region 12E of the second annular element 12 facing the first annular element 11 has a convex curve 141. From Figures 1, 2 and 3, it is clear that the side surface 121 facing the first annular element 11 is typically the side surface of the nozzle ring 10 defining the flow duct 17. In detail, the convex curve 141 extends to the radially inward end of the second annular element 12. Typically, the convex curve 141 is a continuous curve.

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

[0020] According to one embodiment that can be combined with other embodiments described herein, the first annular element 11 is a support ring of the nozzle ring 10. The second annular element 12 can be a cover ring of 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 within 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 that can be combined with other embodiments described herein, in contrast to the first annular element 11, the second annular element 12 comprises an extension 14 that extends exclusively radially inwards, as exemplarily shown in FIG. 2. Thus, material missing from the turbine housing due to manufacturing restrictions can 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 the casting tolerances of the turbine housing in the transition region from the turbine housing to the nozzle ring. As exemplarily shown in FIG. 2, typically, the extension 14 comprises a convex curvature 141. Specifically, the convex curvature 141 extends to the radially inner end of the extension 14. Thus, improved flow guidance in the direction of the turbine wheel can be provided.

[0022] According to one embodiment that can be combined with other embodiments described herein, as exemplarily shown in FIG. 2, the extension 14 has a length L 11 , that is at least 10% of the radial extent R V of the first annular element 11. Alternatively, the length L V can be at least 20% of the radial extent R 11 of the first annular element 11. Exemplarily, the length L V can be at least 30% of the radial extent R 11 of the first annular element 11.

[0023] According to the 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 the axial receiving portion 212 of the 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 inflow 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 outflow side.

[0024] According to one embodiment that can be combined with other embodiments described herein, the axial extension 15 includes a receiving portion 151 for a sealing element 16, as illustrated in Figures 2 and 4. Typically, the receiving portion 151 for the sealing element 16 is located in a radially inward region of the axial extension 15. According to one embodiment not explicitly shown, the receiving portion 151 for the sealing element 16 may be located in a radially outward region of the axial extension 15.

[0025] An exhaust turbine 20, more specifically a radial turbine, according to embodiments of the present disclosure will be described with reference to Figures 3 and 4. 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 disposed within the gas inlet housing 21E. The exhaust turbine is typically mounted on a shaft 24 having a rotational axis 25 attached to a bearing housing 22 and comprises a turbine wheel 23. Furthermore, the exhaust turbine 20 comprises a nozzle ring 10 disposed within the radial gas inlet duct 211. The nozzle ring 10 comprises a first annular element 11, a second annular element 12, and a plurality of guide vanes 13. The guide vanes 13 are disposed between the first annular element 11 and the second annular element 12. The second annular element 12 comprises an end region 12E that extends exclusively radially inward. The end region 12E has a convex curved portion 141 on the side surface 121 facing the first annular element 11. More specifically, the convex curved portion 141 extends to the radially inner end of the second annular element 12. The axial gap S1 is located between the side surface 122 of the second annular element 12 facing away from the first annular element 11 and the opposing side surface 214 of the gas inlet housing 21E.

[0026] Advantageously, an improved exhaust turbine is provided as a result compared to the prior art. In detail, a gas turbine is provided, which can eliminate, at least partially or completely, the aforementioned manufacturing drawbacks in the housing casting process. In detail, an exhaust turbine is provided, which can eliminate the drawbacks and limitations associated with casting for manufacturing a radial turbine with small turbine blades and achieve improvements in flow.

[0027] As illustrated with reference to Figures 2 and 4, in contrast to the first annular element 11, the second annular element 12 has an extension 14 that extends exclusively radially inward. Furthermore, the second annular element 12 may include an axial extension 15 that is at least partially located in the axial housing portion 212 of the gas inlet housing 21E, as illustrated in Figure 4.

[0028] According to one embodiment that can be combined with other embodiments described herein, the axial extension 15 includes a receiving portion 151 for a sealing element 16, in which the sealing element 16 is disposed. 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 metal sheet sealing ring.

[0029] According to one embodiment that can be combined with other embodiments described herein, the axial accommodating portion 212 of the gas inlet housing 21E includes a slanted portion 213 or a rounded portion, as illustrated in Figure 4. Typically, the slanted portion or rounded portion is located in the radially inward region of the axial accommodating portion 212. Providing the slanted portion is convenient for inserting the axial extension 15, together with the sealing element 16, into the axial accommodating portion 212 of the gas inlet housing 21E.

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

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

[0032] Providing gaps S1, S2, and S3 as described herein can be particularly advantageous in minimizing material stress as a result of expansion of the material, especially the nozzle ring, due to temperature.

[0033] It should be noted that the exhaust turbine 20 typically comprises a nozzle ring 10 according to one of the embodiments described herein. It should be further noted that, in light of the embodiments described herein, a turbocharger including the exhaust turbine according to the embodiments described herein can be advantageously provided. [Explanation of symbols]

[0034] 10 Nozzle Rings 11 First annular element / support ring 12 Second annular element / covering 121 Side view of the second annular element facing the first annular element 122 Side view of the second annular element facing the side away from the first annular element 13 Guide vanes 14. Extensions extending radially inward 12E End region of the second annular element facing radially inward 141 Convex curved section 15 Axial extension 151 Seal element receiving part 16 Seal elements 17 Flow duct 20 Exhaust Turbine 21 Turbine Housing 21E Gas Inlet Housing 211 Radial gas inlet duct 212 Axial housing provided in the gas inlet housing for the axial extension 213 Slope 214 Side of the gas inlet housing facing the side of the second annular element that is away from the first annular element. 22 Bearing Housing 23 Turbine Wheel 24 shafts 25. Center of rotation axis S1 Axial gap between radial extension and gas inlet housing S2 Axial gap between the axial extension and the axial receiving portion of the gas inlet housing S3 Radial gap between the axial extension and the axial receiving portion of the gas inlet housing r radial direction x-axis direction S flow direction L V Length of the radial extension of the second annular element / covering R 11 Radial range of the first annular element

Claims

1. A nozzle ring (10) for a radial turbine, the nozzle ring (10) comprises a first annular element (11), a second annular element (12), and a plurality of guide vanes (13) disposed between the first annular element (11) and the second annular element (12), wherein the intermediate space between the first annular element (11) and the second annular element (12) provides a flow duct, and when the nozzle ring (10) is installed, the first annular element (11) defines the flow duct on the bearing housing side, and the second annular element (12) defines the flow duct on the turbine housing side, and the second annular element (12) comprises an axial extension (15) and an extension (14) that extend axially parallel to the rotational axis (25) of the radial turbine, the extension (14) is the radial A nozzle ring (10) is separated from the turbine gas inlet housing (21E) and spaced axially apart, the gas inlet housing (21E) having an inner diameter portion around a shaft (24) having the rotational axis (25), the inner diameter portion having an axially convex curved portion, the extension (14) extending radially inward from the axial extension portion toward the rotational axis (25) of the radial turbine, the extension (14) having a radially inward end region (12E) closest to the rotational axis (25), the radially inward end region (12E) having a convex curved portion (141) on the side surface (121) facing the first annular element (11), and the convex curved portion (141) of the radially inward end region (12E) coincides with the convex curved portion of the inner diameter portion of the gas inlet housing (21E).

2. The nozzle ring (10) according to claim 1, wherein the radially inward end region (12E) has a length LV, and the convex curved portion (141) of the extension (14) extends to LV.

3. The first annular element extends radially inward toward the rotational axis (25) at a distance R 11 It extends to L V The radial range R of the first annular element (11) 11 The nozzle ring (10) according to claim 2, which is at least 10% of the total.

4. The nozzle ring (10) according to claim 1, wherein the axial extension (15) of the second annular element (12) is configured to be inserted into the axial housing (212) of the gas inlet housing (21E) of the turbine housing (21).

5. The nozzle ring (10) according to claim 4, wherein the axial extension (15) is provided with a receiving portion (151) for a sealing element (16).

6. A turbine housing (21) having a gas inlet housing (21E), A radial gas inlet duct (211) is located within the gas inlet housing (21E), A nozzle ring (10) according to any one of claims 1 to 5 is disposed within the radial gas inlet duct (211), An exhaust turbine (20) is provided.

7. The exhaust turbine (20) according to claim 6, wherein an axial gap (S1) exists between the side surface (122) of the extension (14) of the second annular element (12) facing the side away from the first annular element (11) and the opposing side surface (214) of the gas inlet housing (21E).

8. The exhaust turbine (20) according to claim 6, referencing claim 4, wherein the axial extension (15) is at least partially located within the axial housing (212) of the gas inlet housing (21E).

9. The exhaust turbine (20) according to claim 6, referencing claim 5, wherein the sealing element (16) is disposed within the receiving portion (151) for the sealing element (16) to provide a seal between the nozzle ring (10) and the gas inlet housing (21E).

10. The exhaust turbine (20) according to claim 8, wherein the axial housing portion (212) of the gas inlet housing (21E) is provided with an inclined portion (213) or a rounded portion.

11. The exhaust turbine (20) according to claim 10, wherein the inclined portion (213) or the rounded portion is located in the radially inward region of the axial housing portion (212).

12. An axial gap (S2) exists between the end face of the axial extension portion (15) and the axial housing portion (212) of the gas inlet housing (21E), as described in claim 8, for the exhaust turbine (20).

13. The exhaust turbine (20) according to claim 8, wherein a radial gap (S3) exists between the radially outer side of the axial extension (15) and the axial housing (212) of the gas inlet housing (21E).

14. A turbocharger comprising the exhaust turbine (20) according to claim 6.

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