Manufacturing intermediates for turbomachines

Abstract

A manufacturing intermediate for a turbine housing is provided. The manufacturing intermediate is configured for engagement with an abutment portion of the holding device during machining. The manufacturing intermediate includes a connection portion that includes a connection surface that defines a first radius from a central axis. The manufacturing intermediate includes an inlet portion defining a turbine inlet having two inlet volutes axially separated by a partition wall, the partition wall including an end edge defining a second radius from the central axis. The second radius is less than the first radius such that the partition wall defines an alignment surface configured to abut the abutment portion to align the partition wall with the abutment portion.

Description

Technical Field

[0001] This invention relates to manufacturing intermediates for turbine housings, particularly to manufacturing intermediates for turbine housings having two inlet volutes axially separated by partition walls. Manufacturing intermediates including alignment surfaces configured to engage with the abutment portion of a retaining device allow for improved alignment between the partition walls of the turbine housing and the partition walls of the nozzle ring, thereby improving tolerances, reducing assembly time, and improving turbine efficiency. The invention also relates to a method of engaging the manufacturing intermediate of the turbine housing with the abutment portion of the retaining device, a turbine housing, a nozzle ring, and a turbine. Background Technology

[0002] A turbocharger is a well-known device used to supply air to the intake of an internal combustion engine at a pressure higher than atmospheric pressure (boost pressure). A conventional turbocharger includes an exhaust-driven turbine impeller mounted on a rotatable shaft within a turbine housing. The rotation of the turbine impeller causes a compressor impeller mounted on the other end of the shaft within a compressor housing. The compressor impeller delivers compressed air to the engine's intake manifold, thereby increasing engine power. The turbocharger shaft is conventionally supported by journal bearings and thrust bearings, which include a suitable lubrication system, located within a central bearing housing connecting the turbine impeller housing and the compressor impeller housing.

[0003] In known turbochargers, a turbine stage includes: a turbine chamber in which a turbine impeller is mounted; a circumferentially extending inlet passage defined between opposing walls arranged around the turbine chamber; an inlet volute arranged around the inlet passage; and an outlet passage extending from the turbine chamber. The passage communicates with the chamber, allowing pressurized exhaust gas permitted to enter the inlet volute to flow through the turbine and through the inlet passage to the outlet passage, thereby rotating the turbine impeller. It is also known to improve turbine performance by incorporating blades (referred to as nozzle blades) in the inlet passage to deflect the gas flowing through the inlet passage in the direction of rotation of the turbine impeller.

[0004] Turbines can be single-inlet or multi-inlet types. A single-inlet turbine includes a single inlet volute, which typically receives all exhaust gas from an internal combustion engine. A multi-inlet turbine includes more than one volute, which typically receives separate exhaust gas flows from different cylinder banks of an internal combustion engine. One form of multi-inlet turbine is a "two-inlet" turbine, in which two volutes are angled together and extend circumferentially around the turbine axis. In this "two-inlet" turbine, partition walls are used to separate the volutes from each other.

[0005] In multi-inlet turbines, the exhaust flow in different inlet casings will exhibit instantaneous pressure pulses caused by individual cylinder banks. This typically means that when the first casing experiences high pressure, the adjacent second casing experiences low pressure. If the pressure difference between the two casings is high enough, this will cause exhaust gas from the first (higher pressure) casing to overflow the partition wall and enter the second (lower pressure) casing. The presence of high-pressure gas in the second casing can create fluid blockage, which may impede exhaust flow through the second casing during the next exhaust cycle, thereby increasing the pumping work required by the engine and causing engine energy loss. During the next exhaust cycle, high-pressure gas in the second casing can overflow the partition wall into the first casing, creating fluid blockage in the first casing. This fluid interaction between different casings is called "crosstalk."

[0006] It is advantageous to keep the inlet flow streams separated from each other until they are as close as possible to the turbine impeller. By keeping the two flows separated until just before the turbine impeller, this increases the relative pressure difference between the two volutes required for crosstalk to occur. However, this requires the partition walls to be sized such that they extend as close as possible to the turbine impeller in the radial direction. As a result, the partition walls in a dual-inlet turbine casing are typically very long in the radial direction and very narrow in the axial direction. Due to this non-uniform geometry, it is difficult to achieve good alignment between the turbine casing partition walls and the nozzle ring partition walls when assembling the turbomachinery. During operation, maintaining alignment between the nozzle ring partition walls and the turbine casing partition walls becomes even more difficult due to the movement (including rotation) of the nozzle ring. Summary of the Invention

[0007] The object of this invention is to improve machining accuracy in order to provide improved alignment between the nozzle ring partition wall and the turbine housing partition wall. Another object of this invention is to mitigate one or more disadvantages of the prior art, whether described herein or elsewhere, and / or to provide an alternative turbine housing.

[0008] According to a first aspect of the invention, a manufacturing intermediate for a turbine housing is provided, the manufacturing intermediate being configured to engage with an abutment portion of a holding device during machining, the manufacturing intermediate comprising:

[0009] The connecting portion includes a connecting surface that defines a first radius from the central axis;

[0010] The inlet portion defines a turbine inlet having two inlet volutes, the two inlet volutes being axially separated by a partition wall, the partition wall including an end edge defining a second radius from the central axis;

[0011] Wherein, the second radius is smaller than the first radius, such that the partition wall defines an alignment surface, the alignment surface being configured to abut against the abutment portion to align the partition wall with the abutment portion.

[0012] The term "manufacturing intermediate for turbine housing" covers unfinished turbine housings that are further manufactured or machined to produce complete turbine housings. In other words, a manufacturing intermediate is a component used in the manufacture of a turbine housing, and specifically, a component that undergoes subsequent machining to achieve its finished geometry. Such a manufacturing intermediate can also be referred to as a "blank".

[0013] The term "holding device" can cover any suitable means for holding a turbine housing, particularly for holding a turbine housing during machining and / or manufacturing processes. The holding device can be a clamp, and the clamp may include an abutment portion. The holding device can include a chuck, which may have one or more jaws. The jaws of the chuck may define the abutment portion.

[0014] The term "connecting portion" encompasses a part of a manufacturing intermediate configured to connect with another component of the turbine, such as, for example, a heat shield. The connecting surface can rotate about a central axis. Specifically, the central axis can be the central axis of the manufacturing intermediate. In other words, the central axis can be the central axis of the manufactured turbine housing.

[0015] "First radius" refers to the innermost radius of the connecting surface relative to the central axis. "Second radius" refers to the innermost radius of the end edge of the partition wall relative to the central axis.

[0016] The "alignment surface" can be the surface of the partition wall facing the connecting part. That is, the alignment surface can be approached or touched from the connecting part side of the intermediate body.

[0017] In turbines comprising two inlet volutes separated by a partition wall, achieving good alignment between the partition wall of the turbine housing and the corresponding partition wall of the nozzle ring is often difficult. This is because the machining process typically obtains its reference from a radially extending surface of the intermediate body, which defines the axial end of the nozzle passage furthest from the connection portion (e.g., see...). Figure 4Surface 214 in the nozzle channel). Therefore, the width of the nozzle channel has a tolerance relative to the axial side of one of the nozzle channels (defined by dimensions, each with its own tolerance). However, because the precise shape and position of the reference surface itself will vary according to casting tolerances, this results in an impact effect on the machining dimensions based on the tolerance of this reference surface. In particular, this can cause the partition wall of the housing to become misaligned with the partition wall of the nozzle ring. However, by providing a manufacturing intermediate including a partition wall having an alignment surface configured to abut against the abutting portion, a machining reference can be obtained from the alignment surface of the partition wall. Accordingly, the width of the nozzle channel has a tolerance relative to the partition wall, thus providing improved alignment between the partition wall of the housing and the partition wall of the nozzle ring.

[0018] The improved machining accuracy enhances the alignment between the turbine casing partition wall and the nozzle ring partition wall, which in turn improves the flow into the turbine impeller during operation. If misalignment exists between the turbine casing partition wall and the nozzle ring partition wall, a "step" may be present in the inlet flow path from the inlet volute to the turbine impeller, reducing turbine efficiency. Furthermore, the improved machining mitigates the crosstalk caused by the increased clearance path around the periphery of the partitions on the turbine casing partition wall (which also improves efficiency).

[0019] The end edge of the partition wall may include an inwardly extending protrusion that defines the alignment surface, and wherein the protrusion may define the second radius.

[0020] In other words, the end edge may not have a constant radius from the central axis, but can vary according to its orientation angle relative to a specific reference point (such as, for example, the tongue of the inlet portion). Specifically, the end edge may include one or more protrusions. The term "protrusion" encompasses any suitable geometric extension formed in the partition wall and extending toward the central axis. The remainder of the partition wall, excluding protrusions, may have a constant radius.

[0021] Using a protrusion to provide an alignment surface is advantageous, at least because such an alignment surface can be easily positioned from the connecting portion side of the manufacturing intermediate so as to engage with the abutting portion of the retaining device. Therefore, the abutting portion of the retaining device can be easily positioned directly onto the alignment surface.

[0022] Another advantage is that the inwardly extending protrusion can form an anti-rotation feature. Specifically, the inwardly extending protrusion can be received in a corresponding recess in the nozzle ring to prevent the nozzle ring from rotating about its central axis. This protrusion can be configured in any suitable shape to form the anti-rotation feature. The anti-rotation feature improves efficiency by reducing leakage associated with seal ring wear and also by promoting proper alignment of the nozzle ring blades with the housing tongue (partition wall).

[0023] The end edge of the partition wall may define a circumferentially extending base portion with a constant radius from the central axis, wherein the protrusion may extend radially inward from the base portion.

[0024] In other words, the base portion of the partition wall is the part of the partition wall from which the protrusion extends.

[0025] The end edge of the partition wall may include at least three protrusions spaced apart around the central axis.

[0026] Providing at least three protrusions is advantageous because it facilitates the ease of positioning one or more abutting portions of the retaining device against the alignment surface. The end edge of the partition wall may define exactly three protrusions.

[0027] The at least three protrusions may be distributed unevenly around the central axis.

[0028] In other words, the circumferential distance between the centroids of adjacent protrusions is not equal. Or, to put it another way, the angle between the centroid of each protrusion and the central axis may not be equal. Because at least three protrusions are unevenly distributed, proper orientation is required for manufacturing the intermediate body and / or the retaining device to align the abutting portions with the surfaces. This is advantageous because it facilitates proper orientation of the intermediate body during machining.

[0029] Furthermore, in some embodiments, the distance between the central axis and the innermost radial edge of each protrusion can be different. That is, the radial distance between the innermost radial edge of the first protrusion and the central axis is different from the radial distance between the innermost radial edge of the second protrusion and the central axis. Similarly, a third protrusion may be present, having a radial distance from its innermost radial edge to the central axis that is different from that of the first and second protrusions, or this distance may be the same as that of either the first or second protrusion. It is advantageous when the distances from the innermost radial edge of the protrusion to the central axis differ, as this facilitates proper orientation of the manufacturing intermediate during machining.

[0030] It should be understood that in some embodiments, the circumferential distance between the centroids of adjacent protrusions may not be equal, and the distance between the central axis and the innermost radial edge of each protrusion may be different.

[0031] The base portion of the partition wall may define a third radius from the central axis, the third radius being greater than the second radius.

[0032] This ensures that the base portion is wider than the connecting portion. Therefore, the nozzle ring can be accommodated within the space defined by the edge of the partition wall.

[0033] The ratio of the second radius to the first radius is in the range of approximately 0.75 to approximately 0.95.

[0034] The alignment surface is a substantially flat surface located in a plane substantially perpendicular to the central axis.

[0035] It is advantageous for the alignment surface to be located in a plane substantially perpendicular to the central axis because the surface area that the abutting portion of the holding device can abut is increased compared to, for example, if the alignment surface were located in a plane not substantially perpendicular to the central axis. Therefore, the ability of the holding device to hold the manufacturing intermediate during the machining process is improved. However, in alternative embodiments, the alignment surface may be angled or inclined relative to the central axis. For example, if the manufacturing intermediate is part of a mixed-flow turbine in which the nozzle passages extend radially and axially, the alignment surface may be inclined relative to the central axis to the same degree as the nozzle passages.

[0036] The end edge of the partition wall may include a sealing structure.

[0037] The term "sealing structure" encompasses virtually any suitable sealing arrangement, including, for example, mechanical seals and / or fluid seals. For instance, a fluid sealing structure may include a labyrinth seal. In other embodiments, it may include a circumferentially extending groove or recess that receives a sealing member (e.g., an O-ring, etc.). The sealing structure mitigates the travel of fluid exhaust between the two inlet volutes at the interface between the partition wall of the intermediate body and the partition wall of the nozzle ring. Reducing leakage between the two volutes mitigates the decrease in turbine efficiency during operation.

[0038] The fluid seal structure may extend around the entire periphery of the end edge of the partition wall, or it may extend only around a portion of the end edge of the partition wall.

[0039] The end edge of the partition wall may include an inwardly extending protrusion defining an alignment surface, and the protrusion may define a second radius. The end edge of the partition wall may also include a sealing structure extending along at least a portion of the protrusion. Additionally, the sealing structure may extend around the entire periphery of the end edge of the partition wall.

[0040] According to a second aspect of the present invention, a method for manufacturing a turbine housing is provided, the method comprising:

[0041] Obtain the manufacturing intermediate according to any one of the preceding claims;

[0042] Insert the abutting portion of the retaining device into the connecting portion;

[0043] The first surface of the abutting portion abuts against the alignment surface; and

[0044] The second surface of the abutting portion abuts against the connecting surface.

[0045] Because the second radius is smaller than the first radius, the alignment surface protrudes radially inward from the connecting surface. Therefore, the holding device can be easily and readily inserted so that the alignment surface of the manufacturing intermediate engages with the first surface of the abutting portion of the holding device, and the connecting surface of the connecting portion engages with the second surface of the abutting portion of the holding device. A suitable holding device capable of achieving the above can be, for example, a set of radially extendable chuck jaws.

[0046] The method may include machining the manufacturing intermediate.

[0047] Machining the manufacturing intermediate may include performing at least one turning operation and / or at least one milling operation.

[0048] The manufacturing intermediate may include an outlet portion defining a turbine outlet, and the step of machining the manufacturing intermediate may include:

[0049] A turning operation is performed to remove material from the end face of the turbine outlet portion until a predetermined axial distance is achieved between the end face of the outlet portion and the first surface of the abutment portion.

[0050] The predetermined axial distance between the end face of the outlet portion and the first surface of the abutment portion can be referred to as the set dimension.

[0051] The holding device may include a chuck.

[0052] A chuck may include one or more jaws defining an abutment portion. The end surface of each jaw may define a first surface of the abutment portion. The side surface of each jaw may define a second surface of the abutment portion.

[0053] The method may further include:

[0054] Disconnect the holding device from the manufacturing intermediate;

[0055] The end face of the outlet portion engages with the retaining device; and

[0056] The manufacturing intermediates are machined.

[0057] Manufacturing an intermediate may include a turbine impeller chamber portion that defines a turbine impeller chamber. The method may further include performing a turning operation to machine the turbine impeller chamber portion into a predetermined geometry.

[0058] In this context, "predetermined geometry" includes virtually any geometric shape feature that can be produced by machining, including, for example, dimensions, shape, tolerances, surface finish (i.e., surface roughness), etc.

[0059] The manufacturing intermediate may include a bearing housing connection portion configured to be attached to a bearing housing. The method may further include performing a turning operation to machine the bearing housing connection portion to a predetermined geometry.

[0060] The inlet portion may include an annular inlet surface. The method may further include performing a milling operation to machine the annular inlet surface to a predetermined geometry.

[0061] The method may further include performing a milling operation to machine the connecting surfaces to a predetermined geometry.

[0062] The method may further include performing a milling operation to machine one or more fastening holes into the manufacturing intermediate. The fastening holes may be threaded holes.

[0063] The end edge of the partition wall may include an inwardly extending protrusion that defines the alignment surface, and wherein the protrusion may define the second radius; and

[0064] The method may further include performing machining operations to remove material from the partition wall to reduce the size of the protrusion.

[0065] The method may also include performing machining operations to remove material from the partition wall in order to completely remove the alignment surface.

[0066] According to a third aspect of the invention, a turbine housing for a turbocharger is provided, the turbine housing defining:

[0067] The connecting portion includes a connecting surface that defines a first radius from the central axis;

[0068] The inlet portion defines a turbine inlet having two inlet volutes, the two inlet volutes being axially separated by a partition wall, the partition wall including an end edge defining an inwardly extending protrusion;

[0069] Wherein, the protrusion is defined by a second radius smaller than the first radius; and

[0070] The protrusion is configured to be received by a slot of a corresponding shape of the nozzle ring.

[0071] This allows the protrusion to be used as an anti-rotation feature to prevent the nozzle ring from rotating.

[0072] The end edge of the partition wall can define multiple protrusions.

[0073] In particular, the end edge of the partition wall may define at least three protrusions.

[0074] The plurality of protrusions may be distributed unevenly around the central axis.

[0075] If the turbine housing includes unevenly distributed protrusions that can be received in corresponding slots of the nozzle ring, then the corresponding slots of the nozzle ring will also be unevenly distributed around the central axis. This is advantageous because it ensures that the nozzle ring is positioned in the correct orientation within the turbine housing.

[0076] The base portion of the partition wall may define a third radius from the central axis, which may be greater than the second radius.

[0077] The end edge of the partition wall may include a sealing structure.

[0078] The sealing structure can extend around the entire periphery of the end edge of the partition wall.

[0079] According to a fourth aspect of the invention, a nozzle ring for a turbine in a turbocharger is provided, the nozzle ring comprising:

[0080] An annular nozzle ring partition wall surrounding the central axis; and

[0081] Multiple blades extending from the nozzle ring partition wall; and

[0082] The nozzle ring partition wall includes an inwardly recessed slot for receiving a protrusion of the turbine partition wall, the slot being positioned such that the entire slot is angled between two adjacent blades.

[0083] Nozzle rings are positioned within a turbocharger to accelerate and guide flow (particularly exhaust flow) to the turbine impeller at a desired angle. In operation, the nozzle ring partition walls are concentric and axially aligned with the partition walls of the turbine housing, allowing exhaust flow from the turbine's first and second volutes to be guided by multiple blades of the nozzle ring.

[0084] The term "recessed slot" includes any suitable slot or recess such that the end edge of the nozzle ring (i.e., the outer periphery of the nozzle ring) does not have a constant radius measured from the central axis of the nozzle ring. In other words, the radius from the central axis of the nozzle ring to the outer surface of the nozzle ring with the recessed slot is smaller than the radius of the location without the recessed slot.

[0085] It is advantageous for the recessed slot to be configured to receive the protrusion from the turbine because, when the protrusion is received in the recessed slot, the rotation of the nozzle ring about its central axis is constrained, thus preventing any significant rotation of the nozzle ring about the central axis. Preventing nozzle ring rotation is desirable because it leads to turbocharger efficiency losses. During turbine operation, exhaust gas from the internal combustion engine, passing through the inlet volute and proceeding in parallel to the nozzle ring, applies a pressure load to the blades of the nozzle ring. This aerodynamic pressure load on the blades can cause the nozzle ring to move relative to the central axis. This movement of the nozzle ring is undesirable because it leads to increased wear on sealing elements, such as sealing rings and O-rings that at least partially seal the nozzle ring relative to the bearing housing. Wear on these sealing elements can reduce turbine efficiency and performance because increased leakage paths may exist, and this wear can ultimately lead to turbine failure.

[0086] In addition to providing alignment surfaces during turbine manufacturing and assembly, protrusions can also provide anti-rotation features when used in conjunction with recessed slots. The recessed slots in the nozzle ring can have a shape complementary to the protrusions, such that the protrusions are received within the recessed slots. When the protrusions are received in their corresponding recessed slots, they prevent the nozzle ring from rotating about its central axis. Therefore, the protrusions can function as anti-rotation features, preventing rotation of the nozzle ring and consequently reducing wear on the sealing element caused by nozzle ring rotation.

[0087] The term "slot is positioned such that the entire slot is angularly positioned between two adjacent blades" covers situations where the slot does not completely overlap with multiple blades, or does not completely overlap with the extensions of multiple blades.

[0088] The nozzle ring partition wall may include multiple inwardly recessed slots.

[0089] The nozzle ring partition wall may include three inwardly recessed slots. The nozzle ring partition wall may have at least three inwardly recessed slots. The number of slots provided on the nozzle ring may be equal to or greater than the number of protrusions provided on the turbine partition wall.

[0090] Each of the plurality of inwardly recessed slots can be positioned such that the entirety of each slot is angularly positioned between two adjacent blades.

[0091] The plurality of slots may be distributed unevenly around the central axis.

[0092] According to a fifth aspect of the present invention, a turbine for a turbocharger is provided, the turbine comprising:

[0093] Turbine housing according to a third aspect of the invention; and

[0094] According to a fourth aspect of the invention, the nozzle ring wherein the protrusion of the turbine partition wall is received in a slot in the nozzle ring partition wall.

[0095] When the protrusion is received in the slot of the nozzle ring, it constrains the rotation of the nozzle ring about the central axis, thereby preventing any substantial rotation of the nozzle ring about the central axis. Preventing nozzle ring rotation is desirable because it leads to efficiency losses in the turbocharger.

[0096] The protrusion and the slot of the nozzle ring can be complementary in shape. Protrusions and slots with complementary shapes help to further constrain the rotation of the nozzle ring about the central axis. Attached Figure Description

[0097] The following detailed description of one or more exemplary embodiments of the invention is provided with reference to the accompanying drawings, in which:

[0098] Figure 1 This is a schematic cross-sectional view of a known turbocharger;

[0099] Figure 2 This is an end view of a manufacturing intermediate of a turbine housing according to an embodiment of the present invention;

[0100] Figure 3 yes Figure 2 A cross-sectional perspective end view of the opposite end of the manufacturing intermediate shown;

[0101] Figure 4 yes Figure 2 and Figure 3 A cross-sectional perspective side view of the manufacturing intermediate shown;

[0102] Figure 5 yes Figures 2 to 4A cross-sectional perspective side view of a portion of a manufacturing intermediate, wherein a portion of the holding device is positioned within the manufacturing intermediate;

[0103] Figure 6 It is a cross-sectional side view of a manufacturing intermediate having a holding device;

[0104] Figure 7 A front view of a nozzle ring according to an embodiment of the present invention is shown;

[0105] Figure 8 A cross-sectional perspective view of a portion of a nozzle ring positioned within a turbine housing formed from a manufacturing intermediate, according to an embodiment of the invention, is shown; and

[0106] Figure 9 A cross-sectional perspective view of a portion of another embodiment of a nozzle ring positioned within a turbine housing formed from a manufacturing intermediate, according to an embodiment of the invention, is shown. Detailed Implementation

[0107] Figure 1 A schematic cross-section through a known turbocharger is shown. The turbocharger includes a turbine 1 coupled to a compressor 2 via a central bearing housing 3. The turbine 1 includes a turbine impeller 4 for rotation within a turbine housing 5. Similarly, the compressor 2 includes a centrifugal type compressor impeller 6 that can rotate within a compressor housing 7. The compressor housing 7 defines a compressor chamber in which the compressor impeller 6 can rotate. The turbine impeller 4 and the compressor impeller 6 are mounted at opposite ends of a common turbocharger shaft 8 extending through the central bearing housing 3.

[0108] The turbine housing 5 has two inlet volutes 9 positioned annularly around the turbine impeller 4, and an axial exhaust outlet 10. The inlet volutes 9 are configured to receive exhaust from separate cylinder banks of the internal combustion engine. The compressor housing 7 has an axial intake passage (compressor inlet) 11 and an outlet volute 12 arranged annularly around the compressor chamber. The outlet volute 12 is in airflow communication with the compressor outlet 13, which forwards compressed air to the internal combustion engine (not shown).

[0109] Bearing housing 3 defines a bearing chamber through which the turbocharger shaft 8 passes. The shaft 8 is rotatably supported by a bearing assembly comprising two journal bearings 14 and 15 housed facing the turbine end and compressor end of the bearing housing 3, respectively. Oil is supplied to the bearing assembly from the internal combustion engine's oil system via oil inlet 18 and to the bearings 14 and 15 via oil passage 19. The oil supplied to the bearings 14 and 15 can be used to lubricate the bearings and remove heat from them.

[0110] In operation, the turbine impeller 4 rotates about axis 25 as exhaust gas travels from exhaust inlet 9 to exhaust outlet 10. Exhaust gas is supplied from the engine's exhaust manifold (also known as the outlet manifold) to exhaust inlet 9. The turbine impeller 4 then rotates the compressor impeller 6, which thereby draws in intake air through compressor inlet 11 and delivers pressurized air to the engine's inlet manifold via volute 12 and then via outlet 13.

[0111] The compressor chamber is defined between the cover portion 17 of the compressor housing 7 and the hub portion 20 of the bearing housing 3. Figure 1 The compressor housing 7 shown can be formed as a one-piece (i.e., integral) unit including the shroud portion 17, but in alternative embodiments, the compressor housing 7 may include multiple components. The shroud portion 17 has an inwardly facing shroud surface 21 that is circularly symmetrical about the axis of rotation 25.

[0112] Figures 2 to 4 A manufacturing intermediate 105 for a turbine housing is shown. The manufacturing intermediate 105 is used to manufacture the turbine housing and, in particular, is a part that undergoes subsequent machining to achieve its finished geometry. Typically, the manufacturing intermediate 105 is formed by casting, and therefore the precise geometry of the manufacturing intermediate 105 will vary between individual castings, even when using a consistent mold geometry. Therefore, the manufacturing intermediate 105 must undergo one or more machining operations to change its geometry to the desired size and shape.

[0113] refer to Figure 2 , Figure 3 and Figure 4 The intermediate 105 includes an inlet portion 107. The inlet portion 107 includes two inlet volutes 109 (which can...) Figure 4 (Best viewed in the middle). Specifically, the manufacturing intermediate 105 includes a first inlet volute 109a and a second inlet volute 109b terminating at the first nozzle passage 110a and the second nozzle passage 110b, respectively. The first inlet volute 109a and the second inlet volute 109b receive exhaust gas from separate cylinder banks of an internal combustion engine (not shown). The manufacturing intermediate 105 also includes a partition wall 201 that separates the exhaust gas flowing through the first inlet volute 109a from the exhaust gas flowing through the second inlet volute 109b. The partition wall 201 extends generally radially relative to the central axis 203 of the turbine housing 105, such that the first inlet volute 109a and the second inlet volute 109b are positioned axially adjacent to each other. Thus, the manufacturing intermediate 105 can be used to manufacture (and / or can be considered to define) an axially separated double-volute turbine housing. The partition wall 201 is integrally formed with the first inlet volute 109a and the second inlet volute 109b.

[0114] Manufacturing intermediate 105 defines a turbine impeller chamber 111 and a turbine outlet 113, the turbine impeller chamber 111 being configured to include a turbine impeller (not shown), and the turbine outlet 113 being used to receive exhaust gas that has traveled through the turbine impeller.

[0115] The manufacturing intermediate 105 also includes a connecting portion 205 configured to connect with another component of the turbine (e.g., a bearing housing and / or a heat shield). The connecting portion 205 also includes a connecting surface 207. The connecting surface 207 rotates about a central axis 203 and defines a first radius R1 relative to the central axis 203. The first radius R1 is measured as the innermost radius of the connecting surface 207 relative to the central axis 203.

[0116] Returning to partition wall 201, partition wall 201 also includes three inwardly extending protrusions 211. That is, the protrusions 211 extend from partition wall 201 in a direction toward the central axis 203. In particular, the protrusions 211 extend from the base portion 212 of partition wall 201. The base portion 212 defines a constant radius from the central axis 203 and defines the portion of partition wall 201 from which the protrusions 211 extend.

[0117] The inwardly extending protrusion 211 may also be referred to as a positioning pad. The protrusion 211 is integrally formed with the partition wall 201. In other embodiments, the manufacturing intermediate 105 may include fewer than three protrusions (e.g., one or two protrusions), or the manufacturing intermediate 105 may include more than three protrusions (e.g., four, five, or six protrusions).

[0118] The partition wall 201 defines an end edge 209 that extends radially inward along its innermost extent. The end edge 209 is the inner edge of the partition wall 201 relative to the central axis 203 and extends along both the base portion 212 and the protrusions 211. The end edge 209 defines a second radius R2 from the central axis 203. The second radius R2 encompasses the innermost radius of the end edge 209 of the partition wall 201 relative to the central axis 203. Therefore, the second radius R2 is defined at the apex of one or more protrusions 211. Because the partition wall 201 includes inwardly extending protrusions 211, the end edge 209 of the partition wall 201 does not have a constant radius. Therefore, in Figures 2 to 4 In the embodiment shown, the innermost radius of the partition wall 201 is located on the edge of the protrusion 211 closest to the central axis 203.

[0119] The second radius R2 is smaller than the first radius R1. In other words, the distance between the innermost radius of the central axis 203 and the partition wall 201 is smaller than the distance between the central axis 203 and the connecting surface 207.

[0120] The base portion 212 defines a third radius R3 at a distance from the central axis 203. In the illustrated embodiment, the third radius R3 is greater than the second radius R2.

[0121] In other embodiments, the partition wall 201 may not include the inwardly extending protrusion 211 (i.e., the protrusion 211 may not exist), but the second radius R2 may be smaller than the first radius R1 of the connecting surface 207. In embodiments that do not include the protrusion 211, the base portion 212 may define the second radius R2 such that the second radius R2 and the third radius R3 are equal.

[0122] The partition wall 201 also includes an alignment surface 213. The alignment surface 213 is a face or at least a portion of the face of the partition wall 201. Specifically, in Figures 2 to 4 In the illustrated embodiment, the alignment surface 213 is the face of the inwardly extending protrusion 211. The alignment surface 213 is a substantially flat surface located in a plane substantially perpendicular to the central axis 203. In other embodiments, i.e., in embodiments where the partition wall 201 does not include the inwardly extending protrusion 211, the alignment surface 213 may simply be the face of the partition wall 201.

[0123] The alignment surface 213 faces the connecting portion 205. The alignment surface 213 is configured to abut against the retaining device. Figures 2 to 4 The abutment portion (not shown in the image) will be discussed below regarding... Figure 5 To explain in more detail: Because the second radius R2 is smaller than the first radius R1, the alignment surface 213 can be abutted by the retaining device inserted into the manufacturing intermediate 105 at least when the retaining device is inserted via the connecting portion 205. If the second radius R2 is not smaller than the first radius R1, the retaining device will not be able to abut the alignment surface 213. Preferably, the second radius R2 should be about 5% to 20% smaller than the first radius R1 so that the alignment surface 213 can protrude deeply enough to abut the retaining device.

[0124] In some embodiments, the connecting surface 207 defining the first radius R1 may not be concentric with the end edge 209 defining the second radius R2 and / or the base portion 212 defining the third radius R3. Where the first radius R1, the second radius R2, and the third radius R3 cannot be measured from a single concentric point, it should be understood that the surface defining the second radius R2 should be radially inward relative to the central axis 203 of the first radius R1, such that the alignment surface 213 can abut against the retaining device.

[0125] By abutting the retaining device against the alignment surface 213, the alignment surface 213 can be used as a reference point for subsequent machining operations. Therefore, the axial widths of the nozzle channels 110a, 110b relative to the central axis 203 and the axial width 204 of the nozzle partition wall 201, which is centrally positioned between the nozzle channels 110a, 110b, can have tolerances relative to the partition wall 201. This avoids compound tolerance errors caused by so-called tolerance “stacks” from another point of reference in the manufacturing intermediate 105. For example, in prior art methods, the retaining device typically abuts against the side 214 of the second nozzle channel 110b, and then the side 214 is used as a reference point. However, the side 214 of the second nozzle channel 110b can vary from one casting to another, and therefore any subsequent machining operation on the partition wall 201 based on a specific spacing from the side 214 will inherently include geometric variations caused by the casting quality of the side 214, on top of any standard tolerance variations in the machining process based on dimensions determined from the reference. In particular, this can lead to misalignment between the partition wall 201 and the partition wall of the corresponding nozzle ring. In this invention, because the alignment surface 213 is positioned at the center of the nozzle passage and because the alignment surface 213 is used as a reference, this reduces the number of compound tolerance variations defining the nozzle passage and helps improve the alignment between the partition wall 201 and the partition walls of any nozzle rings assembled with the manufacturing intermediate 105. This, in turn, reduces the so-called “crosstalk” occurring between the inlet volutes 109a, 109b (i.e., it provides increased pulse separation into the turbine impeller) and thus reduces the loss of turbine stage efficiency.

[0126] The protrusions 211 are spaced at equal angles around the central axis 203. In other embodiments, the protrusions 211 may be spaced at unequal angles (i.e., the protrusions 211 may be spaced at uneven angles). Unevenly spaced protrusions 211 are advantageous because they ensure the correct orientation of manufacturing intermediates and other tools (e.g., holding devices) during manufacturing and assembly processes. By way of example, this is because when the protrusions are unevenly spaced, if the manufacturing intermediates and / or holding devices are in a particular orientation, the holding device may only be able to abut against the alignment surface 213 (i.e., it may not be able to abut against all orientations).

[0127] Attached to the inwardly extending protrusion 211, the partition wall 201 also includes an extended tongue 215 (see Figure 3 The tongue 215 is configured to be received in a corresponding slot in the nozzle ring. Because the tongue 215 is received in the slot of the nozzle ring, rotation of the nozzle ring about the central axis 203 is prevented. The extended tongue 215 is an optional feature; in other embodiments, the tongue 215 may not be present.

[0128] Figure 5 A cross-sectional perspective side view of a portion of manufacturing intermediate 105 is shown. A portion of holding device 217 is received in manufacturing intermediate 105, and the holding device 217 is arranged to hold manufacturing intermediate 105 in a fixed position. It is necessary to hold manufacturing intermediate 105 in a fixed position in order to perform further manufacturing and / or assembly processes.

[0129] The retaining device 217 defines a plurality of jaw-shaped abutment portions 223 arranged in the chuck. Specifically, the abutment portions 223 include a three-jaw chuck, but in Figure 5 Only the first claw 219 and the second claw 221 are visible. The first claw 219 includes a first surface 250 defining the distal end of the claw and a second surface 225 defining the axially extending outer side of the claw 219. The abutment portion 223 is inserted into the connecting portion 205 of the manufacturing intermediate 105 such that the first surface 250 abuts against the alignment surface 213 of the partition wall 201. The corresponding first surfaces of the remaining claws in the abutment portion 223 contact the alignment surfaces 213 of the remaining protrusions 211. The surface area of ​​the first surface 250 is larger than the surface area of ​​the alignment surface 213, thereby allowing the first surface 250 of the abutment portion 223 to be easily and quickly positioned onto the alignment surface 213.

[0130] As described above, the holding device 217 in this embodiment is a three-jaw chuck. Therefore, the manufacturing intermediate 105 includes three protrusions 211. In other embodiments, where the number of inwardly extending protrusions 211 may be different from three, the number of jaws in the chuck may be equal to the number of inwardly extending protrusions 211. However, even when there are more than three protrusions 211, the chuck may still include only three jaws, which are then capable of abutting at least three of the protrusions 211, which can be advantageous for easily positioning the abutting portion 223 against the alignment surface 213.

[0131] Based on the relative positions of the inwardly extending protrusion 211 and the extended tongue feature 215, the shape of at least one of the claws 219, 221 can be specifically configured such that the abutting portion 223 of the retaining device 217 can engage around the extended tongue feature 215 while still maintaining good contact with the abutting alignment surface 213. Although in Figure 5 A three-jaw chuck is shown, but it should be understood that any suitable holding device that can abut against the alignment surface 213 and hold the manufacturing intermediate / turbine housing during machining and / or manufacturing processes can be used.

[0132] Once the first surface 250 of the claw 219 engages with the alignment surface 213, the holding device 217 is adjusted so that the second surface 225 of the claw 219 abuts against the connecting surface 207 of the connecting portion 205. The corresponding second surfaces of the remaining claws defining the abutment portion 223 also contact the connecting surface 207. The claws 219, 221 of the abutment portion 223 apply an outward radial force to the connecting surface 207, thereby firmly holding the manufacturing intermediate 105 in place.

[0133] refer to Figure 6 The intermediate manufacturing body 105 can be further machined to form a turbine housing for use in a turbocharger. As described above, the intermediate manufacturing body 105 is initially held in place by the holding device 217. Thereafter, the turbine outlet 113 is machined to define the turbine outlet connection portion 227. Specifically, the turbine outlet connection portion 227 is machined such that it has an end face 252 that has a predetermined distance X from the first surface 250 of the abutment portion 223 of the holding device 217. The distance X may be referred to as the so-called “set dimension”. The turbine outlet connection portion 227 can be machined using one or more turning operations to remove unwanted material from the intermediate manufacturing body 105. The one or more turning operations may be so-called “roughing” turning operations or so-called “smoothing” turning operations that provide a specific surface finish / roughness to the turbine outlet 113. One or more machining operations may also include performing machining operations on the turbine outlet 113 using a cutting tool to machine the thickness of the turbine outlet wall 229 to a predetermined thickness. The machining of the turbine outlet wall 229 may also be a “roughing” turning operation or a “smoothing” turning operation. Although the described machining operation is a turning operation, other machining operations, such as milling, may also be used.

[0134] After machining the turbine outlet connection portion 227 and / or the turbine outlet wall 229, a depth micrometer 231 is used to measure the distance from the outlet surface 233 of the turbine outlet connection portion 227 to the first surface 250 of the abutment portion 223 of the retaining device 217. This distance is measured to the first surface 250 of the abutment portion 223 because there is no direct entry line to the surface of the protrusion 211 opposite to the alignment surface 213, since the protrusion 211 has a radius larger than the radius of the turbine outlet passage 113, as measured from the central axis 203 (e.g., in...). Figure 4 (The best one to see).

[0135] Further machining operations can be performed until the predetermined distance X between the exit surface 233 and the abutment portion 223 is achieved.

[0136] Once the predetermined dimensions are achieved, the features of turbine outlet 113 (i.e., the features axially downstream of the turbine impeller during use) can be machined. These further machining steps can be performed using a computer numerical control (CNC) program to produce the features of turbine outlet 113.

[0137] When using the inwardly extending protrusion 211 to provide the set size, the position of the partition wall 211 relative to the turbine outlet connection portion 233 is known.

[0138] The retaining device 217 can then be removed from the connecting portion 205. The retaining device 217 can then be inserted into the manufacturing intermediate 105 via the turbine outlet 113 end. Claws 219, 221 (and an invisible third claw) are positioned against the inner wall 235 of the turbine outlet 113, thus securing the manufacturing intermediate 105 in a fixed position relative to the retaining device 217. Alternatively, this can be achieved using different retaining devices (e.g., including different chuck arrangements) particularly suited for reception within the turbine outlet 113. Further machining operations can then be performed on the turbine impeller chamber 111, the connecting portion 205, and the partition wall 201 to machine these features into the desired final geometry. Because the set dimension X between the alignment surface 213 and the end face 252 of the outlet 113 has already been machined into the manufacturing intermediate 105, further machining operations can obtain their reference from the end face 252 when the retaining device is positioned in the turbine outlet 113. Therefore, tolerances for further machining operations can be controlled based on the relationship between end face 252 and alignment surface 213, which, as described above, is centrally positioned for the nozzle channel. This facilitates accurate alignment with the nozzle ring when it is provided.

[0139] In some embodiments, one of the final machining operations may be machining away the inwardly extending protrusion 211. If the inwardly extending protrusion is machined away, the partition wall 201 will have a constant radius, which is the distance between the central axis 203 and the base portion 212 of the partition wall 201. Alternatively, the protrusion 211 may remain as an anti-rotation feature integrally formed part of the partition wall. The protrusion 211 may be further machined to form a specific shape.

[0140] Figure 7 A front view of the nozzle ring 301 is shown. (As will be...) Figure 8More clearly, the nozzle ring 301 is a nozzle ring for a twin-casing turbine. The nozzle ring 301 includes a nozzle ring partition wall 303, from which a plurality of first blades 305 extend a first face 307. The nozzle ring partition wall 303 is an annular wall surrounding a central axis 203. The nozzle ring partition wall 303 also includes a second face 309 opposite to the first face 307 (in... Figure 7 (Not visible in the middle). The second multiple blades 311 (in Figure 7 (Not visible in the middle) Extends from the second surface 309 in a direction substantially opposite to that of the first plurality of blades 305. The first plurality of blades 305 and the second plurality of blades 311 are configured to guide the flow (especially the exhaust flow) to a desired angle for the turbine impeller during use.

[0141] In use, and as in Figure 8 As can be better seen in the image, the nozzle ring partition wall 303 is concentric and axially aligned with the partition wall 201 of the turbine housing formed by the manufacturing intermediate 105. In use, the exhaust flow from the first and second volutes of the turbine can be guided toward the turbine impeller (not shown) by the plurality of blades 305, 311 of the nozzle ring 301.

[0142] The nozzle ring partition wall 303 includes three inwardly recessed slots 313, such that the end edge 315 of the nozzle ring partition wall 303 (i.e., the outer periphery of the nozzle ring) has a variable radius when measured from the central axis 203.

[0143] Three inwardly recessed slots 313 are configured to receive three inwardly extending protrusions 211 derived from the finished turbine casing of the manufacturing intermediate 105. The inwardly recessed slots 313 are positioned such that the entire slot is angled between two adjacent blades 307. This prevents interference between the slots 313 and the blades 307. In particular, this avoids the need to form part of the blade geometry on the protrusions 211.

[0144] Go to Figure 8The diagram shows a nozzle ring 301 in use, which is received within a turbine housing formed by a manufacturing intermediate 105. A nozzle ring partition wall 303 is axially aligned and concentric with a turbine partition wall 201. An inwardly recessed slot 313 is positioned to receive a corresponding inwardly extending protrusion 211 of the turbine partition wall 201. The inwardly recessed slot 313 has a shape complementary to the protrusion 211. Because the protrusion 211 is received in the slot 313, rotation of the nozzle ring 301 about the central axis 203 is constrained. Constraining the rotation of the nozzle ring 301 mitigates efficiency losses during turbine operation. During turbine operation, exhaust gas from the internal combustion engine, passing through the inlet volute and into the nozzle ring 301, applies a pressure load to the blades 305 of the nozzle ring 301. This aerodynamic pressure load on the blades 305 can cause the nozzle ring 301 to move relative to the central axis 201. Movement of the nozzle ring 301 is undesirable because it leads to increased wear on the sealing element, such as a sealing ring (not shown in this embodiment) that at least partially seals the nozzle ring 301 relative to the bearing housing. Wear on the sealing element can reduce turbine efficiency and performance because there may be increased leakage paths, and this wear may eventually lead to turbine failure.

[0145] In addition to providing an alignment surface during turbine manufacturing and assembly, the protrusion 211 also provides an anti-rotation feature when used in conjunction with the slot 313 in the nozzle ring 301. The slot 313 in the nozzle ring has a shape complementary to that of the protrusion 211, such that the protrusion 211 is received within the slot 211. When the protrusions 211 are received in the corresponding slot 313, they prevent the nozzle ring 301 from rotating about the central axis 203. Therefore, the protrusion 211 acts as an anti-rotation feature, thereby preventing rotation of the nozzle ring 301 and consequently reducing wear on the sealing element caused by rotation of the nozzle ring 301.

[0146] In an alternative embodiment, the nozzle ring 301 may include any number of inwardly recessed slots 313 configured to receive corresponding protrusions 211 of the partition wall 201. However, the number of recessed slots 313 will generally be equal to the number of protrusions 211, otherwise too many recessed slots may result in undesirable exhaust flow between the volutes.

[0147] It should be understood that in the turbine housing formed by the manufacturing intermediate 105, where the inwardly extending protrusion 211 is removed by machining as part of the manufacturing process, the nozzle ring used in the turbine will not include the inwardly extending recess 313, because these recesses would cause the exhaust flow to pass between the two turbine housing volutes, which is undesirable.

[0148] Although in the illustrated embodiment the partition wall 201 and nozzle ring partition wall 303 of the intermediate body 105 extend generally radially relative to the central axis 203, it should be understood that in alternative embodiments, the partition wall 201 and nozzle ring partition wall 303 may extend at a non-radial angle relative to the central axis 203, for example as part of a mixed-flow turbine.

[0149] refer to Figure 9 The end edge 209 of the partition wall 201 of the intermediate body 105 includes a sealing structure 254. The sealing structure 254 is a recessed groove configured to define a fluid seal structure of the type disclosed in the applicant's international patent application WO2020 / 169986. Specifically, the recessed groove is configured to generate turbulence in any exhaust gas traveling through the interface 256 between the outer edge of the nozzle ring partition wall 307 and the end edge 209 of the partition wall 201, thereby mitigating so-called "crosstalk" between the inlet volutes 109a, 109b. Suitable alternative fluid seal arrangements include, for example, labyrinth seals.

[0150] Although the sealing structure 254 described above is a fluid sealing structure, it should be understood that in alternative embodiments, the sealing structure 254 may include any suitable sealing arrangement. In particular, the sealing structure 254 may include a mechanically blocking seal, such as, for example, an O-ring.

Claims

1. A manufacturing intermediate for a turbine housing, the manufacturing intermediate being configured to engage with an abutment portion of a retaining device during machining, the manufacturing intermediate comprising: The connecting portion includes a connecting surface that defines a first radius from the central axis; The inlet portion defines a turbine inlet having two inlet volutes, the two inlet volutes being axially separated by a partition wall, the partition wall including an end edge defining a second radius from the central axis; Wherein the second radius is smaller than the first radius, such that the partition wall defines an alignment surface, the alignment surface being configured to abut against the abutment portion to align the partition wall with the abutment portion.

2. The manufacturing intermediate of claim 1, wherein the end edge of the partition wall includes an inwardly extending protrusion that defines the alignment surface, and wherein the protrusion defines the second radius.

3. The manufacturing intermediate of claim 2, wherein the end edge of the partition wall defines a circumferentially extending base portion having a constant radius from the central axis, and wherein the protrusion extends radially inward from the base portion.

4. The manufacturing intermediate according to claim 2 or claim 3, wherein the end edge of the partition wall includes at least three protrusions spaced apart around the central axis.

5. The manufacturing intermediate according to claim 4, wherein the at least three protrusions are unevenly distributed around the central axis.

6. The manufacturing intermediate according to any one of claims 3 to 5, wherein the base portion of the partition wall defines a third radius from the central axis, the third radius being greater than the second radius.

7. The manufacturing intermediate according to any one of the preceding claims, wherein the ratio of the second radius to the first radius is in the range of about 0.75 to about 0.

95.

8. A manufacturing intermediate according to any of the preceding claims, wherein the alignment surface is a substantially flat surface located in a plane substantially perpendicular to the central axis.

9. The manufacturing intermediate according to any one of the preceding claims, wherein the end edge of the partition wall includes a sealing structure.

10. A method for manufacturing a turbine housing, the method comprising: Obtain the manufacturing intermediate according to any one of the preceding claims; Insert the abutting portion of the retaining device into the connecting portion; The first surface of the abutting portion abuts against the alignment surface; and The second surface of the abutting portion abuts against the connecting surface.

11. The method of claim 10, wherein the method comprises: The manufacturing intermediates are machined.

12. The method according to any one of claims 11, wherein, The machining of the manufacturing intermediates includes: Perform at least one turning operation and / or at least one milling operation.

13. The method of claim 11 or claim 12, wherein the manufacturing intermediate includes an outlet portion defining a turbine outlet, and wherein the step of machining the manufacturing intermediate includes: A turning operation is performed to remove material from the end face of the turbine outlet portion until a predetermined axial distance is achieved between the end face of the outlet portion and the first surface of the abutment portion.

14. The method according to any one of claims 10 to 13, wherein the holding device comprises a chuck.

15. The method according to any one of claims 10 to 14, wherein the method further comprises: Disconnect the holding device from the manufacturing intermediate; The end face of the outlet portion is engaged with the retaining device; as well as The manufacturing intermediates are machined.

16. The method of any one of claims 10 to 15, wherein the end edge of the partition wall includes an inwardly extending protrusion defining the alignment surface, and wherein the protrusion defines the second radius; and The method further includes: Machining operations are performed to remove material from the partition wall to reduce the size of the protrusion.

17. The method according to any one of claims 10 to 16, wherein the method further comprises: Perform machining operations to remove material from the partition wall in order to completely remove the alignment surface.

18. A turbine housing for a turbocharger, the turbine housing defining: The connecting portion includes a connecting surface that defines a first radius from the central axis; The inlet portion defines a turbine inlet having two inlet volutes, the two inlet volutes being axially separated by a partition wall, the partition wall including an end edge defining an inwardly extending protrusion; The protrusion is defined by a second radius smaller than the first radius; and The protrusion is configured to be received by a slot of a corresponding shape of the nozzle ring.

19. The turbine housing of claim 18, wherein the end edge of the partition wall defines a plurality of protrusions.

20. The turbine housing of claim 19, wherein the plurality of protrusions are unevenly distributed around the central axis.

21. The turbine housing according to any one of claims 18 to 20, wherein the end edge of the partition wall includes a sealing structure.

22. The turbine housing of claim 21, wherein the sealing structure extends around the entire periphery of the end edge of the partition wall.

23. A nozzle ring for a turbine in a turbocharger, the nozzle ring comprising: An annular nozzle ring partition wall surrounding the central axis; and Multiple blades extending from the nozzle ring partition wall; and The nozzle ring partition wall includes an inwardly recessed slot for receiving a protrusion of the turbine partition wall, the slot being positioned such that the entire slot is angled between two adjacent blades.

24. The nozzle ring of claim 23, wherein the nozzle ring partition wall comprises a plurality of inwardly recessed slots.

25. The nozzle ring of claim 24, wherein each of the plurality of inwardly recessed slots is positioned such that the entirety of each slot is angularly positioned between two adjacent blades.

26. The nozzle ring of claim 24 or claim 25, wherein the plurality of slots are unevenly distributed around the central axis.

27. A turbine for a turbocharger, the turbine comprising: Turbine housing according to any one of claims 18 to 22; and According to any one of claims 23 to 26, the nozzle ring wherein the protrusion of the turbine partition wall is received in the slot of the nozzle ring partition wall.

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