Method for manufacturing a dual vane nozzle ring assembly for a turbocharger with a dual scroll turbine housing

Abstract

The present invention relates to a method for manufacturing a double-vane nozzle ring assembly for a turbocharger with a twin-scroll turbine housing for directing exhaust gas from each scroll to a turbine wheel in a staggered manner. A double-vane nozzle ring for a turbine nozzle of a turbocharger nozzle ring is manufactured by assembling a nozzle ring from three separately formed parts. The central portion includes a first ring of circumferentially spaced first blades and a second ring of circumferentially spaced second blades, the first ring and the second ring being axially spaced and integrally connected to each other. The first blade is circumferentially offset from the second blade, and the outlet of the first blade passage is radially aligned with the outlet of the second blade passage and circumferentially staggered. The first sidewall and the second sidewall are arranged as separate parts. Finally, the first sidewall is connected to the distal face or outer surface of the first ring, and the second sidewall is connected to the distal face of the second ring to complete the assembly.

Description

Technical Field

[0001] The present disclosure relates to turbochargers in which the turbine of the turbocharger is driven by exhaust gas from a reciprocating engine. The invention more particularly relates to a turbine housing divided into a plurality of substantially separate sections, each section being fed by a separate exhaust system. Background Art

[0002] An exhaust-driven turbocharger is a device used in conjunction with an internal combustion engine to increase the power output of the engine by compressing air delivered to the intake of the engine to be mixed with fuel and burned in the engine. A turbocharger includes a compressor wheel mounted on one end of a shaft in a compressor housing and a turbine wheel mounted on the other end of the shaft in a turbine housing. Typically, the turbine housing is formed separately from the compressor housing, and there is another center housing connected between the turbine housing and the compressor housing for accommodating the bearings of the shaft. The turbine housing defines a generally annular chamber that surrounds the turbine wheel and receives exhaust gas from the engine. The turbine assembly includes a nozzle leading from the chamber to the turbine wheel. Exhaust gas flows from the chamber through the nozzle to the turbine wheel, and the turbine wheel is driven by the exhaust gas. The turbine thus extracts power from the exhaust gas and drives the compressor. The compressor receives ambient air through the inlet of the compressor housing, and the air is compressed by the compressor wheel and then discharged from the housing to the engine intake.

[0003] In multi-piston reciprocating engines, it is known to design the exhaust system in such a way as to take advantage of the pressure pulsations that occur in the exhaust gas flow. In particular, it is known to employ so-called "pulse separation", in which the cylinders of the engine are divided into a plurality of groups and the pulses from each group of cylinders are substantially isolated from the pulses from the other groups by providing each group of cylinders with an independent exhaust passage. In order to fully exploit the advantages of pulse separation, it is desirable to minimize the communication or "crosstalk" between the separated groups of cylinders. Thus, in the case of a turbocharged engine, it is advantageous to always maintain separate exhaust passages into the turbine of the turbocharger. Therefore, the turbine housing into which the exhaust gas is fed is usually divided into a plurality of substantially separate parts.

[0004] There are two basic ways to divide a turbine housing: (1) sector division and (2) meridian division. In a sector-divided turbine housing, a generally annular chamber is divided into angular sectors, each of which occupies only a portion of the circumference, so that the passages are continuous with each other in the circumferential direction, such as in U.S. Pat. No. 6,260,358. Figure 2 The sectoring of the turbine housing is advantageous from a flow separation point of view, but out-of-phase exhaust pulses from the two sectors may induce undesirable turbocharger shaft motions.

[0005] In a meridional divided turbine housing, the scroll or chamber surrounding the turbine wheel and supplying exhaust gas thereto is divided into a plurality of scrolls which are continuous with one another in the axial direction, each scroll occupying substantially the entire circumference, such as shown in FIG. 4 of U.S. Patent No. 4,027,994. The meridional division of the turbine housing is advantageous from the perspective of shaft movement, but the exhaust gas flow impingement from each scroll is less than the entire axial width of the leading edge of the turbine blade, which has a negative impact on turbine efficiency due to mixing losses.

[0006] The present disclosure relates to a turbocharger having a turbine housing of a meridian split type. Summary of the invention

[0007] The present disclosure relates to a turbocharger having a meridionally divided scroll, and in particular to a method for manufacturing a double-vane nozzle ring that allows separate exhaust gas flows from two scrolls to blow onto a turbine impeller in a staggered manner around the circumference of the impeller. According to the embodiments described and illustrated herein, a method for manufacturing a double-vane nozzle ring assembly for a turbine nozzle of a turbocharger includes the following steps:

[0008] (a) providing the first side wall as an annular portion;

[0009] (b) providing a second side wall as an annular portion, the second side wall being formed separately from the first side wall;

[0010] (c) providing a nozzle ring separate from the first sidewall and the second sidewall, wherein the nozzle ring is configured to have a first blade ring including first blades circumferentially spaced about the circumference of the nozzle ring, and configured to have a second blade ring including second blades circumferentially spaced about the circumference of the nozzle ring, the first blade ring and the second blade ring being axially spaced apart and integrally connected to each other, the first blade ring defining first blade passages between circumferentially consecutive first blades, and the second blade ring defining second blade passages between circumferentially consecutive second blades, wherein the first blade passages have respective first blade passage inlets and first blade passage outlets, wherein the second blade passages have respective second blade passage inlets and second blade passage outlets, wherein the first blades are circumferentially offset from the second blades, the first blade passage inlets are axially spaced apart from the second blade passage inlets, and the first blade passage outlets are radially aligned with and circumferentially staggered from the second blade passage outlets; and

[0011] (d) Joining the first side wall to the distal end surface of the first blade ring, and joining the second side wall to the distal end surface of the second blade ring.

[0012] Since each of the two blade rings blows exhaust gas all the way around its circumference on the turbine impeller, and the jets from the first blade passage and the second blade passage are staggered around the circumference, the nozzle ring assembly manufactured according to the method of the present invention can alleviate shaft motion and mixing loss problems that may affect some prior art turbines of the sector-divided and meridian-divided types. The nozzle ring assembly manufactured according to the present invention can maintain good flow isolation between the two exhaust gas flows all the way to the turbine impeller, thereby fully utilizing and separating the exhaust manifold pressure pulses.

[0013] In some embodiments, there may be symmetry between the first vane passage and the second vane passage in that the first vane passage and the second vane passage have substantially equal respective flow areas. However, in other embodiments, the flow area of ​​the first vane passage may be different from the flow area of ​​the second vane passage, such that one scroll contributes a greater portion of the total exhaust flow than the other scroll, while the volumes of the first scroll and the second scroll may optionally be equal.

[0014] In some embodiments, the first blade passage may be configured such that each first exhaust jet strikes the entire extent of the leading edge of the turbine blade, and similarly, the second blade passage may be configured such that each second exhaust jet strikes the entire extent of the leading edge of the turbine blade. In other embodiments, each of the first blade passage and the second blade passage may be configured such that the first exhaust jet and the second exhaust jet strike less than the entire extent of the leading edge.

[0015] According to one embodiment of the present invention, the first side wall may include a plurality of recessed blade accommodating portions in the surface of the first side wall facing the distal surface of the first blade ring, each of the recessed blade accommodating portions receiving the distal end of the corresponding first blade. Similarly, the second side wall may include a plurality of recessed blade accommodating portions in the surface of the second side wall facing the distal surface of the second blade ring, each of the recessed blade accommodating portions receiving the distal end of the corresponding second blade.

[0016] The nozzle ring may be manufactured by an injection molding process, a non-limiting example of which is a metal injection molding (MIM) process.

[0017] The assembly of the first side wall and the second side wall with the nozzle ring can be achieved by using pins. In one embodiment, each side wall and two opposing distal faces of the nozzle ring are provided with pin receiving portions, and the pin receiving portions in each side wall are aligned with corresponding pin receiving portions in the corresponding faces of the nozzle ring. Pins are press-fitted into the pin receiving portions in each face of the nozzle ring and into the pin receiving portions of each side wall to complete the assembly.

[0018] In another embodiment, the first blade ring and the second blade ring include an integrally formed pin that protrudes from each of the opposed distal faces of the nozzle ring, and the sidewall includes a pin receiving portion. The pin is inserted into the pin receiving portion in the sidewall and then secured therein, such as by riveting or any other suitable fastening technique. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Having thus described the present disclosure in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and in which:

[0020] Figure 1 is an axial cross-sectional view of a turbocharger having a double-vane nozzle ring assembly, which can be made by the method according to the present invention;

[0021] Figure 2 is an isometric view of a nozzle ring assembly according to a first embodiment of the present invention;

[0022] Figure 3 is an exploded view of a nozzle ring assembly according to a first embodiment of the present invention;

[0023] Figure 4A is an isometric view of a nozzle ring component of the nozzle ring assembly of the first embodiment;

[0024] Figure 4B is another isometric view of the nozzle ring component of the first embodiment;

[0025] Figure 5A is an exploded view of a first side wall and a second side wall of a nozzle ring assembly of a first embodiment;

[0026] Figure 5B is another exploded view of the first side wall and the second side wall of the first embodiment;

[0027] Figure 6 is a schematic end view of a nozzle ring assembly, used to explain Figure 7 and Figure 8 The location of the cross-sectional view;

[0028] Figure 7 is a nozzle ring assembly according to a first embodiment of the present invention. Figure 6 A cross-sectional view taken along line 7-7;

[0029] Figure 8 The nozzle ring assembly according to the first embodiment is Figure 6 A cross-sectional view taken along line 8-8;

[0030] Fig.9A is an isometric view of a nozzle ring component for a nozzle ring assembly according to a second embodiment of the present invention;

[0031] Fig. 9B is another isometric view of the nozzle ring component of the second embodiment;

[0032] Fig.10 is similar to Figure 7 , but for a second embodiment of the invention, at an intermediate stage of the assembly operation;

[0033] Fig.11 is similar to Figure 8 , but for a second embodiment, at an intermediate stage of the assembly operation;

[0034] Fig. 10A and Fig.10 a nozzle ring assembly similar but showing the second embodiment after the assembly operation is completed; and

[0035] Fig.11A and Fig.11 Similarly, the nozzle ring assembly of the second embodiment is shown after the assembly operation is completed. DETAILED DESCRIPTION

[0036] The present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all, embodiments of the invention are shown. Indeed, the inventions may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that the present disclosure will satisfy applicable legal requirements. Throughout the text, like numbers represent like elements. In this document, references to "radial," "circumferential," and "axial" (or equivalently, to cylindrical coordinates r, θ, z, respectively) are relative to the turbocharger axis of rotation, with the axial direction being along or parallel to the axis of rotation, the radial direction extending perpendicularly from the axis of rotation, and the circumferential direction surrounding the axis of rotation.

[0037] Figure 1 1 shows a turbocharger 10 suitable for using a nozzle ring assembly made according to the present invention. The turbocharger includes a compressor wheel or impeller 14 disposed in a compressor housing 16 and mounted on one end of a rotatable shaft 18. The shaft is supported in a bearing 19, which is mounted in a center housing 20 of the turbocharger. The shaft 18 is rotated by a turbine wheel 22 mounted on the other end of the shaft 18 spaced from the compressor impeller, thereby rotatably driving the compressor impeller, which compresses air drawn in through the compressor inlet and delivers the compressed air to a volute 21, which collects the compressed air for supply to the intake of an internal combustion engine (not shown) to increase the performance of the engine.

[0038] The turbocharger also includes a turbine housing 24 that accommodates the turbine wheel 22. As previously mentioned, in a reciprocating internal combustion engine having a plurality of cylinders, it is advantageous to design the exhaust system in such a way that the pressure pulsations occurring in the exhaust gas stream discharged from the cylinders are utilized. In particular, it is advantageous to employ so-called "pulse separation", in which the cylinders of the engine are divided into a plurality of groups, and the pulses from each group of cylinders are substantially isolated from the pulses of the other groups by having a separate exhaust passage for each group. In order to fully exploit the advantages of pulse separation, it is desirable to minimize the communication or "crosstalk" between the separated cylinder groups. In the case of a turbocharged engine, it is advantageous to maintain separate exhaust passages all the way into the turbine of the turbocharger. To this end, the turbine housing typically has a separate scroll member, which includes two separate scroll members that respectively receive the separate exhaust gas streams.

[0039] Therefore, if Figure 1 As shown, the turbine housing 24 defines a meridian-divided scroll member, which includes a first scroll member 26a and a second scroll member 26b, which are separated from each other by a partition wall 27. The second scroll member is immediately adjacent to the first scroll member in the axial direction of the turbocharger, and each scroll member receives exhaust gas via a separate exhaust inlet defined by the turbine housing. According to the present invention, the two exhaust gas flows are isolated from each other through a nozzle ring assembly 30 until the turbine impeller 22, and the nozzle ring assembly 30 guides the two exhaust gas flows to the turbine impeller separately. The nozzle ring assembly is disposed in the turbine housing 24 adjacent to the center housing 20.

[0040] refer to Figure 2 , the nozzle ring assembly 30 defines a first vane ring 40 including first vanes 42 circumferentially spaced about the circumference of the nozzle ring, and a second vane ring 50 including second vanes 52 circumferentially spaced about the circumference of the nozzle ring. The first ring 40 defines first vane passages 44 between circumferentially consecutive first vanes 42. Similarly, the second ring 50 defines second vane passages 54 between circumferentially consecutive second vanes 52. The first vane passages 44 are circumferentially staggered relative to the second vane passages 54. In other words, the array of second vanes 52 is circumferentially "clockwise" about the nozzle ring axis relative to the array of first vanes 42 by an angular amount less than the angular spacing between adjacent first vanes. In the illustrated embodiment, the second vane passage is circumferentially staggered relative to the first vane passage by approximately half of the circumferential spacing between the leading edge of one first vane 42 and the leading edge of the next first vane 42 in the circumferential direction. Fluid isolation of the two sets of vane passages 44 and 54 is achieved by a partition 49 comprising a generally annular wall, wherein the ends of the first vanes 42 are joined to one face of the partition 49 and the ends of the second vanes 52 are joined to the opposite face of the partition.

[0041] The nozzle ring assembly 30 includes a first end wall 46 and a second end wall 56. The first end wall 46 is axially spaced from the baffle 49, and the end of the first vane 42 opposite the baffle is connected to the first end wall. The second end wall 56 is axially spaced on the other side of the baffle, and the end of the second vane 52 opposite the baffle is connected to the second end wall. In order to prevent the nozzle ring assembly from rotating relative to the turbine casing 24, the nozzle ring can be provided with an anti-rotation feature or multiple such features. In one non-limiting embodiment, the anti-rotation feature can include one or more pins 32 ( Figure 1 ). The nozzle ring assembly may define receptacles in the second end wall 56 (or alternatively, or additionally, in the first end wall 46) that align with corresponding receptacles in the turbine housing 24, and each pair of aligned receptacles may be held in alignment by one of the anti-rotation pins 32. In the exemplary embodiment, there are three such anti-rotation pins that are circumferentially spaced about the circumference of the nozzle ring. Other types of anti-rotation features are possible in the practice of the present invention, examples of which include, but are not limited to, radially oriented pins that engage in holes or slots in the turbine housing, integral features such as protrusions formed on the nozzle ring assembly for engaging corresponding slots or recesses in the turbine housing, and the like.

[0042] The radially innermost end of the partition wall 27 of the turbine housing 24 is adjacent to the radial outer periphery of the partition plate 49 of the nozzle ring assembly 30, as shown in FIG. Figure 1 The interface between the dividing wall and the nozzle ring may be sealed with a seal, such as an O-ring or any other suitable type of seal. Alternatively, however, it may be desirable in certain circumstances to have a defined gap between the dividing wall and the nozzle ring, the size of the gap being selected to adjust the degree of fluid isolation between the two exhaust gas flows.

[0043] The first vane passage 44 is positioned to receive exhaust gas only from the first scroll 26a, and the outlet of each first vane passage 44 directs the first exhaust gas jet onto the turbine blade leading edge. Similarly, the second vane passage 54 is positioned to receive exhaust gas only from the second scroll 26b, and the outlet of each second vane passage 54 directs the second exhaust gas jet onto the turbine blade leading edge.

[0044] Due to the circumferential offset between the two sets of blades 42 and 52, the leading edge of the turbine blades receives the first exhaust jet and the second exhaust jet respectively from the first blade passage 44 and the second blade passage 54 in a staggered manner around the circumference of the turbine impeller. That is, one circumferential sector of the impeller receives the first exhaust jet from the first blade passage, the adjacent circumferential sector receives the second exhaust jet from the second blade passage, the next circumferential sector receives the first exhaust jet from the next adjacent first blade passage, and so on in an alternating or staggered manner around the entire circumference of the impeller.

[0045] As previously described, the nozzle ring assembly according to an embodiment of the present invention can alleviate some of the disadvantages of both the meridian-divided and sector-divided turbine housing designs according to the prior art. With respect to the sector-divided turbine housing, out-of-phase pulses from two 180-degree sectors aimed at the turbine impeller can cause undesirable turbocharger shaft movement. In contrast, the nozzle ring assembly of the present invention evenly distributes the out-of-phase pulses around the circumference of the turbine impeller, thereby tending to reduce or eliminate such excessive shaft movement. With respect to the meridian-divided turbine housing, since each vortex supplies exhaust gas only to approximately half of the width of the leading edge of the turbine blade, a large amount of mixing losses will occur, which has an adverse effect on turbine efficiency. The nozzle ring assembly according to an embodiment of the present invention can alleviate both the shaft movement problem and the mixing loss problem because the two vortex members alternately (i.e., in a staggered manner) supply exhaust gas around the entire circumference (and in some embodiments can also blow the exhaust gas over the entire range of the leading edge of the turbine blade).

[0046] The nozzle ring assembly provides the ability to control the flow distribution between the two scrolls. For example, by sizing the vane passages of one scroll smaller than the vane passages of the other scroll, an uneven or asymmetric flow distribution can be achieved. In such cases, it may be advantageous for the scrolls to have equal volumes.

[0047] The shapes of the inlet and outlet sides of the blade passages 44 and 54 can be selected by the designer. In some embodiments, the blade passage outlets can be roughly rectangular; in other embodiments, they can be elliptical. The inlet of a given blade passage does not necessarily have to have a shape similar to the passage outlet. For example, the blade passage inlet can be rectangular and the outlet can be circular or elliptical, or vice versa. In the case mentioned above, in which the blade passage of one scroll is smaller than the blade passage of the other scroll, the shape of the blade passage outlet can be different between the two scrolls. As a non-limiting example, the blade passage outlet for one scroll can be rectangular, and the blade passage outlet for another scroll can be elliptical and have a flow area smaller than the rectangular outlet.

[0048] In the illustrated embodiment, the second blade passages 54 are circumferentially offset relative to the first blade passages 44 so that there is no circumferential overlap between a given second exhaust jet and an adjacent first exhaust jet. However, the invention is not limited in this sense, and in other (not shown) embodiments, the blades may be configured so that there is some circumferential overlap between the respective first and second exhaust jets. Additionally, in other (not shown) embodiments, each of the first and second blade rings may blow exhaust gas over less than the entire width or extent of the leading edge of the turbine blade, and in that case there may be overlap in the axial direction (and optionally also in the circumferential direction) between the first and second exhaust jets.

[0049] The present invention particularly relates to a method for producing Figure 2 The nozzle ring assembly 30 shown in the figure. According to the present invention, the nozzle ring assembly includes three main components, such as Figure 3 Shown: nozzle ring 60, first side wall 46, and second side wall 56 defining vanes. These three components are made as separate parts and subsequently assembled to form nozzle ring assembly 30, as described below. Nozzle ring 60 can be manufactured by an injection molding process, a non-limiting example of which is a metal injection molding (MIM) process.

[0050] refer to Figure 4A and Figure 4B The nozzle ring 60 includes the first blade ring 40 as previously described, which includes the first blades 42 circumferentially spaced around the circumference of the nozzle ring, and includes the second blade ring 50, which includes the second blades 52 circumferentially spaced around the circumference of the nozzle ring. The first blade ring and the second blade ring are axially spaced and integrally connected to each other (and to the intermediate diaphragm 49). As previously described, the first blades 42 are circumferentially offset from the second blades 52, and the first blade passage inlet 44 is axially spaced from the second blade passage inlet 54, as shown in FIG. Figure 1 and Figure 2 As shown, but as Figure 1 As shown, the first blade passage outlet is radially aligned with the second blade passage outlet (ie, the first blade passage outlet and the second blade passage outlet are not axially spaced apart but occupy substantially the same axial extent), and they are circumferentially staggered with respect to one another.

[0051] refer to Figure 5A and Figure 5B , the first side wall 46 is an annular (or ring-shaped) portion whose axial outer surface is generally planar. The outer diameter (OD) of the first side wall is substantially equal to the maximum diameter of the first blades 42 at their leading edges (see Figure 2 ), and the inner diameter (ID) of the first sidewall is substantially equal to the minimum diameter of the first blades at their trailing edges. The axial thickness of the first sidewall is relatively small at the OD and increases in the radially inward direction, having a substantially maximum thickness at the ID. Therefore, the inner surface of the first sidewall does not extend radially, but is inclined relative to the radial direction. The inner surface defines a plurality of recessed blade receiving portions 47 therein, each of which is configured to receive the distal end of a corresponding one of the first blades 42. The recessed blade receiving portions 47 reduce or eliminate exhaust gas leakage between the distal end of the first blade and the inner surface of the first end wall 46.

[0052] The second sidewall 56 is substantially a mirror image of the first sidewall, with its inner surface defining a plurality of recessed vane receiving portions 57 for receiving the distal ends of the second vanes 52, but the recessed vane receiving portions 57 are circumferentially offset or "clockwise" relative to the vane receiving portions 47, corresponding to the manner in which the second vanes 52 are rotated clockwise relative to the first vanes 42 as previously described. The recessed vane receiving portions 57 reduce or eliminate exhaust gas leakage between the distal ends of the second vanes and the inner surface of the second end wall 56.

[0053] Now the main reference Figure 3 , Figure 4A , Figure 4B , Figure 5A , Figure 5B , Figure 6 , Figure 7 and Figure 8 A method of assembling the nozzle ring 60 with the sidewalls 46 and 56 is described. The nozzle ring 60 defines a first pin receiving portion 61 in the distal end of each of a plurality of circumferentially spaced first vanes 42, the illustrated embodiment showing three such first pin receiving portions 61 ( Figure 4A and Figure 4B ). On the first side wall 46 ( Figure 5A and Figure 5B ) defines a corresponding pin receiving portion 48 in the first side wall, each pin receiving portion 48 in the first side wall being aligned with a corresponding pin receiving portion 61 in the nozzle ring 60. Similarly, the nozzle ring defines a second pin receiving portion 62 in the distal end of each of a plurality of circumferentially spaced second vanes 52, of which there are three such second pin receiving portions 62 in the illustrated embodiment ( Figure 4A and Figure 4B A corresponding pin receiving portion 58 is defined in the second side wall 56 ( Figure 5A and Figure 5B ).

[0054] refer to Figure 3 , Figure 7 and Figure 8 , the first side wall 46 is fixed to one side of the nozzle ring 60 by a first pin P1, which is press-fitted into the pin receiving portion 48 in the first side wall and into the first pin receiving portion 61 in the nozzle ring, as shown Figure 8 Similarly, the second side wall 56 is secured to the other side of the nozzle ring by a second pin P2 which is press fit into a pin receiver 58 in the second side wall and into a second pin receiver 62 in the nozzle ring, as shown in FIG. Figure 7 The best view in Figure 2 The assembly of the nozzle ring assembly 30 is shown.

[0055] exist Fig.9A , Fig. 9B , Fig.10 , Fig. 10A, Fig.11 and Fig.11A A second embodiment of the present invention is shown in FIG. Fig.9A and Fig. 9B As shown, the second embodiment is generally similar to the first embodiment, except that the first pin P1 and the second pin P2 are integral structures of the nozzle ring 60. The first pin P1 is inserted into the pin receiving portion 48 in the first side wall 46 ( Fig.11 ), and then fixed therein, such as by riveting ( Fig.11A ). Similarly, the second pin P2 is inserted into the pin receiving portion 58 in the second side wall 56 ( Fig.10 ), and then fixed therein, such as by riveting ( Fig. 10A ).

[0056] Many modifications and other embodiments of the invention set forth herein will occur to those skilled in the art having benefit of the teachings given in the foregoing description and the associated drawings. Therefore, it should be understood that the invention is not limited to the specific embodiments disclosed, and modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used only in a general and descriptive sense and not for purposes of limitation.

Claims

1. A method for manufacturing a double-vane nozzle ring assembly for a turbine nozzle of a turbocharger, the method comprising the following steps: (a) providing the first side wall as an annular portion; (b) providing a second side wall as an annular portion, the second side wall being formed separately from the first side wall; (c) providing a nozzle ring separate from the first sidewall and the second sidewall, wherein the nozzle ring is configured to have a first blade ring, the first blade ring including first blades circumferentially spaced around the circumference of the nozzle ring, and a second blade ring, the second blade ring including second blades circumferentially spaced around the circumference of the nozzle ring, the first blade ring and the second blade ring being axially spaced apart and integrally connected to each other, the first blade ring defining first blade passages between circumferentially consecutive first blades, the second blade ring defining second blade passages between circumferentially consecutive second blades, wherein the first blade passages have respective first blade passage inlets and first blade passage outlets, wherein the second blade passages have respective second blade passage inlets and second blade passage outlets, wherein the first blades are circumferentially offset from the second blades, the first blade passage inlets are axially spaced apart from the second blade passage inlets, and the first blade passage outlets and the second blade passage outlets occupy or extend the same axial extent, and the first blade passage outlets and the second blade passage outlets are circumferentially staggered; as well as (d) Joining the first side wall to the distal end surface of the first blade ring, and joining the second side wall to the distal end surface of the second blade ring.

2. The method of claim 1, wherein step (a) comprises configuring the first side wall to include a plurality of recessed blade receiving portions in a surface of the first side wall facing the distal surface of the first blade ring, each of the recessed blade receiving portions receiving a distal end portion of a corresponding first blade.

3. The method of claim 1, wherein step (b) comprises configuring the second side wall to include a plurality of recessed blade receiving portions in a surface of the second side wall facing the distal surface of the second blade ring, each of the recessed blade receiving portions receiving a distal end portion of a corresponding second blade.

4. The method of claim 1, wherein step (c) comprises manufacturing the nozzle ring by an injection molding process. The method of claim 4 , wherein the injection molding process comprises a metal injection molding (MIM) process.

6. The method of claim 1 , wherein the first side wall and the first blade ring are each configured to define a plurality of circumferentially spaced pin receiving portions, the pin receiving portions of the first side wall being aligned with the pin receiving portions of the first blade ring, and wherein step (d) comprises press-fitting pins into the pin receiving portions of the first blade ring and into the pin receiving portions of the first side wall.

7. The method of claim 1 , wherein the second side wall and the second blade ring are each configured to define a plurality of circumferentially spaced pin receiving portions, the pin receiving portions of the second side wall being aligned with the pin receiving portions of the second blade ring, and wherein step (d) comprises press-fitting pins into the pin receiving portions of the second blade ring and into the pin receiving portions of the second side wall.

8. The method of claim 1, wherein the first blade ring is configured to include a plurality of circumferentially spaced pins protruding from the distal end surface of the first blade ring, and the first side wall is configured to include a plurality of circumferentially spaced pin receiving portions, and wherein step (d) includes inserting the pins of the first blade ring into the pin receiving portions of the first side wall and securing the pins therein.

9. The method of claim 8, wherein the step of securing the pin in the pin receiving portion comprises riveting the pin.

10. The method of claim 1, wherein the second blade ring is configured to include a plurality of circumferentially spaced pins protruding from the distal end surface of the second blade ring, and the second side wall is configured to include a plurality of circumferentially spaced pin receiving portions, and wherein step (d) includes inserting the pins of the second blade ring into the pin receiving portions of the second side wall and securing the pins therein.

11. The method of claim 10, wherein the step of securing the pin in the pin receiving portion comprises riveting the pin.

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