Variable capacity turbo and supercharger

Abstract

A variable capacity turbocharger has a variable nozzle unit for adjusting the flow of exhaust gas in an exhaust gas flow path for guiding exhaust gas to a turbine rotor. The variable nozzle unit includes a plurality of nozzle vanes arranged at a spaced interval in the circumferential direction of the turbine rotor on the exhaust gas flow path. When the exhaust gas flow path is divided into a tongue vicinity region located in the vicinity of a tongue of the turbine rotor and a region other than the tongue vicinity region, i.e., a tongue far region, the plurality of nozzle vanes includes at least one tongue vicinity nozzle vane located in the tongue vicinity region and at least one tongue far nozzle vane located in the tongue far region, and at least one of a leading edge end or a trailing edge end of the tongue vicinity nozzle vane has a cutout portion that is larger than a cutout portion of the leading edge end or the trailing edge end of the tongue far nozzle vane.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a variable capacity turbine and a supercharger provided with the variable capacity turbine.

[0002] This application claims priority based on Japanese Patent Application No. 2021-008254 filed on January 21, 2021 in the Japan Patent Office, the contents of which are hereby incorporated by reference. BACKGROUND

[0003] As an exhaust gas turbocharger that supercharges intake air of an internal combustion engine (engine) using energy of exhaust gas of the internal combustion engine, there is known a variable capacity type exhaust gas turbocharger provided with a variable capacity turbine (for example, refer to Patent Literature 1). The variable capacity turbine is provided with a plurality of nozzle vanes arranged side by side in the circumferential direction on an exhaust gas flow path for transporting exhaust gas from a scroll flow path of the turbine to a turbine rotor, and by changing a blade angle of the nozzle vanes from the outside using an actuator, it is possible to adjust a flow path cross-sectional area of the exhaust gas flow path (flow path between adjacent nozzle vanes). The variable capacity turbine changes a flow rate or pressure of exhaust gas guided to the rotor by adjusting the flow path cross-sectional area of the exhaust gas flow path, and improves a supercharging effect.

[0004] In Patent Literature 1, it is disclosed that by using a cutout portion provided at a central portion in the blade height direction of a trailing edge of a nozzle vane, exhaust gas in the vicinity of an intermediate position of the exhaust gas flow path is discharged in advance, and a clearance flow based on a pressure difference is reduced.

[0005] PRIOR ART DOCUMENTS

[0006] PATENT LITERATURE

[0007] Patent Literature 1: Japanese Patent Application Publication No. H11-229815 SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] However, the load applied to the nozzle vane changes with pulsation of the internal combustion engine (engine). Due to the load acting on the nozzle vane, a clearance between a blade shaft fixed to the nozzle vane and other components that support the nozzle vane becomes narrow, and there is a case where the blade shaft and the other components come into contact. In the operation of the variable capacity turbine, if the contact of the blade shaft and the other components occurs frequently, wear can occur on the blade shaft and become a cause of damage.

[0010] In a short period of about one pulsation cycle of the internal combustion engine, the risk of the above-described contact and the occurrence of wear on the vane shaft are high in a case where the direction of action of the load acting on the vane shaft is reversed, and therefore measures need to be taken. In particular, the nozzle vane disposed in the vicinity of the tongue portion of the scroll flow passage is affected by the slope (flow deformation) generated at the tongue portion when exhaust gas flows, and therefore in a short period of about one pulsation cycle of the internal combustion engine, there is a case where the direction of action of the load acting on the vane shaft is reversed. Note that Patent Document 1 does not address the technical problem of suppressing wear of the vane shaft accompanying pulsation of the internal combustion engine (engine).

[0011] In view of the above-described circumstances, an object of at least one embodiment of the present disclosure is to provide a variable capacity turbo that can improve reliability and durability of the variable capacity turbo by suppressing wear of the vane shaft, and a supercharger provided with the variable capacity turbo.

[0012] Technical solution for solving the problem

[0013] One embodiment of the present disclosure provides a variable capacity turbo that includes:

[0014] a turbine rotor;

[0015] a scroll flow passage forming portion that forms a scroll flow passage on an outer peripheral side of the turbine rotor;

[0016] an exhaust gas flow passage forming portion that forms an exhaust gas flow passage for guiding exhaust gas from the scroll flow passage to the turbine rotor;

[0017] a variable nozzle unit that adjusts flow of the exhaust gas in the exhaust gas flow passage,

[0018] the variable nozzle unit includes:

[0019] a plurality of nozzle vanes that are disposed at intervals along a circumferential direction of the turbine rotor on the exhaust gas flow passage;

[0020] a rotation mechanism portion configured to rotate the plurality of nozzle vanes around respective rotation centers,

[0021] when the exhaust gas flow passage is divided into a tongue portion vicinity region located in the vicinity of a tongue portion of the scroll flow passage and a region other than the tongue portion vicinity region, i.e., a tongue portion far region, the plurality of nozzle vanes include at least one tongue portion vicinity nozzle vane located in the tongue portion vicinity region and at least one tongue portion far nozzle vane located in the tongue portion far region,

[0022] the at least one tongue portion vicinity nozzle vane has a cutout portion that is larger than a cutout portion of the leading edge end or the trailing edge end of the tongue portion far nozzle vane, at least one of the leading edge end or the trailing edge end of the tongue portion vicinity nozzle vane.

[0023] One embodiment of the present disclosure provides a supercharger including:

[0024] the variable displacement turbine;

[0025] a centrifugal compressor configured to be driven by the variable displacement turbine.

[0026] Effects of Invention

[0027] According to at least one embodiment of the present disclosure, there is provided a variable displacement turbine capable of improving reliability and durability of the variable displacement turbine by suppressing wear of a blade shaft, and a supercharger including the variable displacement turbine. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a schematic configuration view schematically showing a configuration of an internal combustion engine system including a supercharger of one embodiment of the present disclosure.

[0029] Figure 2 is a schematic cross-sectional view schematically showing a turbine side of a supercharger including a variable displacement turbine of one embodiment of the present disclosure.

[0030] Figure 3 is a view for explaining a variable nozzle unit of one embodiment of the present disclosure.

[0031] Figure 4 is a view for explaining a configuration of a nozzle blade of one embodiment.

[0032] Figure 5 is a view for explaining a CFD analysis condition for simulating pulsation conditions of an internal combustion engine.

[0033] Figure 6 is a view for explaining a load evaluation result of a nozzle blade near a tongue portion of a comparative example.

[0034] Figure 7 is a view for explaining a load evaluation result of a nozzle blade far from a tongue portion of a comparative example.

[0035] Figure 8 is a view showing a negative pressure surface of a nozzle blade far from a tongue portion of one embodiment.

[0036] Figure 9 is a view showing a negative pressure surface of a nozzle blade near a tongue portion of one embodiment.

[0037] Figure 10 is a view showing a negative pressure surface of a nozzle blade near a tongue portion of one embodiment.

[0038] Figure 11 is a view showing a negative pressure surface of a nozzle blade near a tongue portion of one embodiment.

[0039] Figure 12 FIG. 1 is a view showing a negative pressure surface of a tongue portion distal nozzle vane according to an embodiment.

[0040] Figure 13 FIG. 1 is a view showing a negative pressure surface of a tongue portion distal nozzle vane according to an embodiment. Figure 9 FIG. 1 is a view showing a negative pressure surface of a tongue portion distal nozzle vane according to an embodiment.

[0041] Figure 14 FIG. 1 is a view showing a negative pressure surface of a tongue portion distal nozzle vane according to an embodiment.

[0042] Figure 15 FIG. 1 is a view showing a negative pressure surface of a tongue portion distal nozzle vane according to an embodiment.

[0043] Figure 16 FIG. 1 is a view showing a negative pressure surface of a tongue portion distal nozzle vane according to an embodiment.

[0044] Figure 17 FIG. 1 is a view showing a negative pressure surface of a tongue portion distal nozzle vane according to an embodiment.

[0045] Figure 18 FIG. 1 is a view showing a negative pressure surface of a tongue portion distal nozzle vane according to an embodiment.

[0046] Figure 19 FIG. 1 is a view showing a negative pressure surface of a tongue portion distal nozzle vane according to an embodiment.

[0047] Figure 20 FIG. 1 is a view showing a negative pressure surface of a tongue portion distal nozzle vane according to an embodiment. Figure 17 FIG. 1 is a view showing a negative pressure surface of a tongue portion distal nozzle vane according to an embodiment.

[0048] Figure 21 FIG. 1 is a view showing a negative pressure surface of a tongue portion distal nozzle vane according to an embodiment. DETAILED DESCRIPTION

[0049] Hereinafter, some embodiments of the present disclosure will be described with reference to the accompanying drawings. Note that the size, the material, the shape, the relative arrangement, and the like of the constituent parts shown in the drawings that are described as embodiments are not intended to limit the scope of the present disclosure, and are merely illustrative.

[0050] For example, expressions such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric", or "coaxial" that indicate relative or absolute arrangement not only strictly indicate such arrangement, but also indicate a state in which there is a tolerance or a relative displacement of an angle or a distance that achieves the same degree of function.

[0051] For example, expressions such as "same", "equal", and "uniform" indicating a state of equality of things indicate not only a state of strict equality but also a state of difference with a tolerance or a state of obtaining a same degree of function.

[0052] For example, expressions such as "quadrilateral shape" or "cylindrical shape" indicating a shape indicate not only a shape in the strict sense of a quadrilateral shape or a cylindrical shape but also a shape including a concave-convex portion or a chamfered portion or the like within a range of obtaining a same effect.

[0053] On the other hand, expressions such as "provided with", "including", or "having" a component are not exclusive expressions excluding the presence of other components.

[0054] Note that there are cases where the same symbol is assigned to the same structure and the explanation is omitted.

[0055] (Booster)

[0056] Figure 1 is a schematic configuration view schematically indicating a configuration of an internal combustion engine system provided with a booster of an embodiment of the present disclosure. In each of the embodiments below, an exhaust gas turbocharger 1A is exemplified and described, but the present disclosure can be applied to a booster 1 other than the exhaust gas turbocharger 1A.

[0057] As shown in Figure 1 , the booster 1 of some embodiments includes the exhaust gas turbocharger 1A configured to be driven by the energy of exhaust gas discharged from an internal combustion engine 10 (engine) and to compress a fluid (for example, air). As shown in Figure 1 , the booster 1 (exhaust gas turbocharger 1A) is provided with a variable capacity turbine 2 and a centrifugal compressor 3 configured to be driven by the variable capacity turbine 2.

[0058] As shown in Figure 1 , the booster 1 is provided with a rotation shaft 11, a turbine rotor 21 provided on one side (right side in Figure 1 ) of the rotation shaft 11, an impeller 31 provided on the other side (left side in Figure 1 ) of the rotation shaft 11, a bearing 12 configured to support the rotation shaft 11 so as to be rotatable, and a housing 13 configured to house them (the rotation shaft 11, the turbine rotor 21, the impeller 31, and the bearing 12).

[0059] In the illustrated embodiment, the housing 13 includes a turbine housing 22 configured to house the turbine rotor 21, a compressor housing 32 configured to house the impeller 31, and a bearing housing 14 configured to house the bearing 12. The variable capacity turbine 2 is provided with the above-described turbine rotor 21 and the above-described turbine housing 22. The centrifugal compressor 3 is provided with the above-described impeller 31 and the above-described compressor housing 32.

[0060] Hereinafter, a direction in which the axis LA of the rotation shaft 11 extends is set as an axial direction X of the rotation shaft 11, and a direction orthogonal to the axis LA is defined as a radial direction Y. A side of the turbine rotor 21 with respect to the side on which the impeller 31 is located in the axial direction X is set as a turbine side XT, and a side opposite to the turbine side XT, that is, a side of the impeller 31 with respect to the turbine rotor 21 in the axial direction X is defined as a compressor side XC. In addition, there are cases where an outer side in the radial direction Y is simply denoted as an outer peripheral side, and an inner side in the radial direction Y is simply denoted as an inner peripheral side.

[0061] The bearing housing 14 is disposed between the turbine housing 22 and the compressor housing 32 in the axial direction X. The bearing 12 is located between the turbine rotor 21 and the impeller 31 in the axial direction X, and is supported by the bearing housing 14. The bearing housing 14 can also be fastened to the turbine housing 22 and the compressor housing 32, respectively, by fastening members (for example, bolts) that are not shown.

[0062] The compressor housing 32 has a gas introduction port 33 for introducing a gas into an inside thereof, and a gas discharge port 34 for discharging the gas that has passed through the impeller 31 to the outside. The gas introduction port 33 is formed at an end portion of the supercharger 1 in the axial direction X (an end portion of the compressor side XC), and opens toward the compressor side XC.

[0063] A gas introduction passage 35 for guiding the gas introduced from the outside of the compressor housing 32 through the gas introduction port 33 to the impeller 31, and a spiral flow passage 37 for discharging the gas that has passed through the impeller 31 to the outside through the gas discharge port 34 are formed in the inside of the compressor housing 32. The gas introduction passage 35 extends along the axial direction X. The spiral flow passage 37 is formed at the outer peripheral side of the impeller 31.

[0064] The compressor housing 32 has a gas introduction passage forming portion 36 that forms the gas introduction passage 35, and a spiral flow passage forming portion 38 that forms the spiral flow passage 37. The gas introduction port 33 is formed at an upstream end of the gas introduction passage forming portion 36, and the gas discharge port 34 is formed at a downstream end of the spiral flow passage forming portion 38. The impeller 31 is configured to guide the gas introduced from the compressor side XC along the axial direction X to the outer side in the radial direction Y.

[0065] The turbine housing 22 has a exhaust gas introduction port 23 for introducing an exhaust gas into an inside thereof, and an exhaust gas discharge port 24 for discharging the exhaust gas that has passed through the turbine rotor 21 to the outside. The exhaust gas discharge port 24 is formed at the other end portion of the supercharger 1 in the axial direction X (an end portion of the turbine side XT), and opens toward the turbine side XT.

[0066] A scroll flow path 25 for guiding exhaust gas introduced from the outside of the turbine housing 22 through the exhaust gas introduction port 23 toward the turbine rotor 21, and an exhaust gas discharge path 27 for discharging exhaust gas that has passed through the turbine rotor 21 and the exhaust gas discharge port 24 to the outside are formed inside the turbine housing 22. The exhaust gas discharge path 27 extends along the axial direction X. The scroll flow path 25 is formed on the outer peripheral side of the turbine rotor 21.

[0067] The turbine housing 22 has a scroll flow path forming portion 26 that forms the scroll flow path 25, and an exhaust gas discharge path forming portion 28 that forms the exhaust gas discharge path 27. The exhaust gas discharge port 24 is formed at the downstream end of the exhaust gas discharge path forming portion 28. The turbine rotor 21 is configured to guide exhaust gas introduced from the outside in the radial direction Y toward the turbine side XT along the axial direction X.

[0068] The supercharger 1 is provided with a gas pipe 15 for guiding gas from the centrifugal compressor 3 toward the internal combustion engine 10, and an exhaust gas pipe 16 for guiding exhaust gas from the internal combustion engine 10 toward the variable capacity turbine 2. The gas pipe 15 includes a pipe 151, one side of which is connected to the internal combustion engine 10, and the other side of which is connected to the gas discharge port 34 of the centrifugal compressor 3. The exhaust gas pipe 16 includes a pipe 161, one side of which is connected to the internal combustion engine 10, and the other side of which is connected to the exhaust gas introduction port 23 of the variable capacity turbine 2.

[0069] Gas that has passed through the impeller 31 and the scroll flow path 37 of the centrifugal compressor 3 is guided to the internal combustion engine 10 (engine) through the gas pipe 15 for combustion in the internal combustion engine 10. Exhaust gas generated due to combustion in the internal combustion engine 10 is guided to the turbine rotor 21 through the exhaust gas pipe 16 and the scroll flow path 25 of the variable capacity turbine 2.

[0070] The supercharger 1 is configured to rotate the turbine rotor 21 by the energy of exhaust gas discharged from the internal combustion engine 10. The impeller 31 is mechanically linked to the turbine rotor 21 via the rotation shaft 11, and thus rotates in conjunction with the rotation of the turbine rotor 21. The supercharger 1 is configured to compress gas that has passed through the impeller 31 by the rotation of the impeller 31, increase the density of the gas, and deliver the gas to the internal combustion engine 10.

[0071] (VARIABLE CAPACITY TURBINE)

[0072] Figure 2 is a schematic cross-sectional view that schematically shows the turbine side of the supercharger provided with the variable capacity turbine of one embodiment of the present disclosure. In Figure 2 , a cross section of the supercharger 1 along the axis LA of the rotation shaft 11 is schematically shown.

[0073] As shown in Figure 2As shown, the variable capacity turbine 2 includes the aforementioned turbine rotor 21, the aforementioned vortex flow path forming section 26 forming a vortex flow path 25 on the outer periphery of the turbine rotor 21, the aforementioned exhaust flow path forming section 4 forming an exhaust flow path (nozzle flow path) 40 for guiding exhaust gas from the vortex flow path 25 to the turbine rotor 21, and a variable nozzle unit 5 for adjusting the exhaust gas flow in the exhaust flow path 40. The exhaust flow path 40 is formed between the vortex flow path 25 and the turbine rotor 21 in a manner that surrounds the turbine rotor 21 (outer side of radial Y).

[0074] (Exhaust gas flow path formation section)

[0075] like Figure 2 As shown, the exhaust gas flow path forming section 4 includes a nozzle seat 41 fixed to the housing 13 and a nozzle plate 42 disposed on the turbine side XT of the nozzle seat 41 and defining the exhaust gas flow path 40 between the nozzle plate 42 and the nozzle seat 41. Hereinafter, the compressor side XC in the exhaust gas flow path 40 may be referred to as the hub side, and the turbine side XT in the exhaust gas flow path 40 may be referred to as the shield side.

[0076] The nozzle seat 41 includes an annular plate portion 43 extending circumferentially along the outer periphery of the turbine rotor 21. The nozzle seat 41 has a hub-side flow surface 44 formed on the turbine side XT of the annular plate portion 43. In the illustrated embodiment, the nozzle seat 41 is fixed to the housing 13 by being clamped between the turbine housing 22 and the bearing housing 14 by the outer periphery of the annular plate portion 43.

[0077] The nozzle plate 42 includes an annular plate portion 45 extending circumferentially along the outer periphery of the turbine rotor 21 and a protrusion 46 protruding axially from the inner periphery of the annular plate portion 45 toward the turbine side XT. The nozzle plate 42 has a shroud-side flow surface 47 formed on the compressor side XC of the annular plate portion 45 and a shroud surface 48 connected to the shroud-side flow surface 47 and curved into a convex shape. The shroud surface 48 is formed on the inner periphery of the annular plate portion 45 and forms a gap (clearance) between it and the blade tip of the turbine rotor 21.

[0078] The exhaust gas path 40 is defined between the hub side flow path 44 and the shield side flow path 47. The hub side flow path 44 and the shield side flow path 47 extend in a direction that intersects (e.g., orthogonally) the axis LA of the rotation axis 11. The shield side flow path 47 is located on the turbine side XT, opposite to the hub side flow path 44.

[0079] The exhaust gas flow path forming portion 4 can further include at least one nozzle support member 49 that supports the nozzle seat 41 and the nozzle plate 42 in a state of being separated from each other. The at least one nozzle support member 49 is fixed to the annular plate portion 43 of the nozzle seat 41 on one side thereof and is fixed to the annular plate portion 45 of the nozzle plate 42 on the other side thereof. The nozzle plate 42 is supported by the at least one nozzle support member 49 in a state of being separated from the nozzle seat 41 in the axial direction X. In the illustrated embodiment, the at least one nozzle support member 49 includes a plurality of nozzle support members 49 that are arranged at intervals in the circumferential direction of the turbine rotor 21. That is, the exhaust gas flow path forming portion 4 includes the plurality of nozzle support members 49.

[0080] The exhaust gas introduced into the inside of the turbine housing 22 passes through the scroll flow path 25 and then passes through the exhaust gas flow path 40, after which it is guided to the turbine rotor 21 to rotate the turbine rotor 21. The exhaust gas that has passed through the turbine rotor 21 is discharged from the exhaust gas discharge port 24 to the outside of the turbine housing 22 after passing through the exhaust gas discharge path 27.

[0081] (VARIABLE NOZZLE UNIT)

[0082] As Figure 2 illustrated, the variable nozzle unit 5 includes a plurality of nozzle vanes 6 arranged at intervals in the circumferential direction of the turbine rotor 21 in the exhaust gas flow path 40 described above, and a rotation mechanism portion 51 configured to rotate the plurality of nozzle vanes 6 about respective rotation centers RC. The variable nozzle unit 5 changes the blade angle of the plurality of nozzle vanes arranged in the exhaust gas flow path 40 by the rotation mechanism portion 51, whereby it is possible to adjust the flow path cross-sectional area of the exhaust gas flow path 40. The variable displacement turbine 2 increases and decreases the flow path cross-sectional area of the exhaust gas flow path 40 by the variable nozzle unit 5, whereby it is possible to change the flow rate or pressure of the exhaust gas guided to the turbine rotor 21, whereby it is possible to control the boost pressure of the variable displacement turbine 2.

[0083] As Figure 2 illustrated, the rotation mechanism portion 51 includes an annular drive ring 52 provided to be rotatable with respect to the nozzle seat 41 in the circumferential direction of the turbine rotor 21, a plurality of vane shafts 53, a plurality of lever plates 54, an actuator 55 configured to rotate the drive ring 52 about an axis LC thereof, and a controller 57 (control device) configured to control the drive (i.e., the amount of movement in the circumferential direction about the axis LC) of a drive shaft 56 of the actuator 55.

[0084] Figure 3 is a diagram for explaining the variable nozzle unit of one embodiment of the present disclosure. In Figure 3 , the state of the variable nozzle unit 5 as viewed from the compressor side XC in the axial direction X is schematically represented.

[0085] As Figure 3As shown, the rotation mechanism section 51 includes the blade shaft 53 and the lever plate 54 in the same number as the number of the nozzle vanes 6 included in the variable nozzle unit 5. For the blade shaft 53, one side is fixed to the nozzle vane 6, and the other side is mechanically coupled to one side of the lever plate 54. The other side of the lever plate 54 is mechanically coupled to the drive ring 52. The actuator 55 includes an electric motor or a pneumatic cylinder, or the like. The drive shaft 56 of the actuator 55 is mechanically coupled to the drive ring 52.

[0086] The plurality of lever plates 54 each include an engagement portion 541 that is engaged with an engagement portion 521 formed in the drive ring 52. The engagement portion 521 includes a groove portion 522 formed in the outer peripheral portion of the drive ring 52, and the engagement portion 541 is configured to be housed inside the groove portion 522 and loosely engaged with the groove portion 522.

[0087] As shown, Figure 3 The nozzle seat 41 has a plurality of insertion holes 411 formed at separate positions spaced apart from each other in the circumferential direction around the axis LA. The nozzle seat 41 has the same number of insertion holes 411 as the number of the nozzle vanes 6 included in the variable nozzle unit 5. The plurality of blade shafts 53 are each rotatably inserted into one of the plurality of insertion holes 411.

[0088] As shown, Figure 2 As shown, the annular plate portion 43 of the nozzle seat 41 on the side opposite the hub side flow path surface 44 (compressor side XC) and the annular groove portion 141 formed in the turbine side XT of the bearing housing 14 form an annular inner space 17 inside them. The drive ring 52 and the plurality of lever plates 54 are housed in the above-mentioned inner space 17 formed inside the housing 13.

[0089] In the power transmission path from the actuator 55 to the plurality of nozzle vanes 6, the drive shaft 56 and the drive ring 52, the drive ring 52 and the lever plate 54, and the lever plate 54 and the blade shaft 53 are each coupled to each other. If the actuator 55 is driven by the controller 57, the drive ring 52 rotates with the axis LC as the center of rotation in response to the movement of the drive shaft 56 of the actuator 55. If the drive ring 52 rotates, the plurality of nozzle vanes 6 rotate around the respective centers of rotation RC in response to the rotation of the drive ring 52 via the lever plate 54 and the blade shaft 53, and change the vane angle thereof.

[0090] If the drive ring 52 is rotated to one side in the circumferential direction, circumferentially adjacent nozzle vanes 6 are moved in directions away from each other, and the exhaust gas flow path 40 between the nozzle vanes 6, that is, the flow path cross-sectional area of the exhaust gas flow path 40, becomes larger. In addition, if the drive ring 52 is rotated to the other side in the circumferential direction, circumferentially adjacent nozzle vanes 6 are moved in directions toward each other, and the exhaust gas flow path 40 between the nozzle vanes 6, that is, the flow path cross-sectional area of the exhaust gas flow path 40, becomes smaller. The direction of rotation in which the flow path cross-sectional area of the exhaust gas flow path 40 is increased is set as the opening direction, and the direction of rotation in which the flow path cross-sectional area of the exhaust gas flow path 40 is decreased is set as the closing direction.

[0091] Figure 4 is a view for explaining the configuration of the nozzle vane in one embodiment. In Figure 4 , the state of the variable capacity turbine 2 as viewed from the turbine side XT in the axial direction X is schematically shown.

[0092] As shown in Figure 4 , the plurality of nozzle vanes 6 (7, 8) each have a vane surface 60 (70, 80) including one surface, that is, a pressure surface 60A (70A, 80A), extending between a leading edge end 61 (71, 81) and a trailing edge end 62 (72, 82), and another surface, that is, a negative pressure surface 60B (70B, 80B), extending between the leading edge end 61 and the trailing edge end 62. The negative pressure surface 60B is located on the inner side in the radial direction Y compared to the pressure surface 60A. The trailing edge end 62 is located on the downstream side in the flow direction of the exhaust gas compared to the leading edge end 61. Note that the pressure surface 60A and the negative pressure surface 60B of the plurality of nozzle vanes 6 can also have a curved shape.

[0093] As shown in Figure 2 , the plurality of nozzle vanes 6 (7, 8) each have a hub side end 63 (73, 83) in which a gap (clearance) is formed between the hub side flow path surface 44 of the nozzle seat 41, and a shroud side end 64 (74, 84) in which a gap (clearance) is formed between the shroud side flow path surface 47 of the nozzle plate 42.

[0094] The scroll flow path forming portion 26 has a tongue portion 29 that protrudes toward the scroll flow path 25 in a plane as viewed from the side of the axial direction X (turbine side XT) of the rotation shaft 11 as shown in Figure 4 . The tongue portion 29 refers to the connection point of the winding start 261 and the winding end 262 in the scroll flow path forming portion 26.

[0095] As shown in Figure 4The exhaust gas flow path 40 is divided into a tongue vicinity region 40A located near the tongue 29 of the scroll flow path 25 and a tongue far region 40B outside the tongue vicinity region 40A, in a plane shown, visually confirmed from the side of the axial direction X of the rotation shaft 11 (e.g., the turbine side XT). The tongue vicinity region 40A is set as a region in which at least the nozzle vane 6 (7A) closest to the tongue 29 is present, and the tongue far region 40B is set as a region in which at least the nozzle vane 6 (8B) farthest from the tongue 29 is present.

[0096] The plurality of nozzle vanes 6 includes at least one tongue vicinity nozzle vane 7 located in the tongue vicinity region 40A and at least one tongue far nozzle vane 8 located in the tongue far region 40B. The tongue vicinity nozzle vane 7 includes the above-described nozzle vane 7A, and the tongue far nozzle vane 8 includes the above-described nozzle vane 8B.

[0097] (Blade shaft wear)

[0098] Figure 5 is a view for explaining a CFD analysis condition for simulating pulsation conditions of an internal combustion engine. As shown in Figure 5 , to simulate the pulsation conditions of the internal combustion engine 10, CFD analysis is performed under a pressure condition in which the inlet pressure of the variable capacity turbine 2 is increased and decreased between a lower limit value PL and an upper limit value PU in one cycle T1 of the internal combustion engine 10, and the change in load acting on the nozzle vane 6 is investigated.

[0099] Figure 6 is a view for explaining a load evaluation result of a tongue vicinity nozzle vane of a comparative example. Figure 7 is a view for explaining a load evaluation result of a tongue far nozzle vane of a comparative example. Figure 8 is a view showing a negative pressure surface of a tongue far nozzle vane of one embodiment. Figure 6 、 Figure 7 The load evaluation object, i.e., the nozzle vane, in Figure 8 is the same shape as the nozzle vane 6 (tongue far nozzle vane 8) shown in , and when the negative pressure surface 60B (80B) thereof is set to the front view, the leading edge end 61 (81) and the trailing edge end 62 (82) each extend in a straight line from the hub side end 63 (83) to the shroud side end 64 (84) in a direction in which the rotation center RC extends.

[0100] In Figure 6 and Figure 7 , the load VL acting on the nozzle vane is evaluated in a ratio in which the maximum load in a certain direction (positive direction) is set to 100%. In Figure 6In the drawing, VL1 and VL2 indicate a load acting on the nozzle vane 7A closest to the tongue 29 under a pressure condition of the lower limit value PL of the pressure and a load acting on the nozzle vane 7A under a pressure condition of the upper limit value PU of the pressure. The direction of action of the load VL2 and the load VL1 is reversed. In Figure 7 In the drawing, VL3 and VL4 indicate a load acting on the nozzle vane 8B farthest from the tongue 29 under a pressure condition of the lower limit value PL of the pressure and a load acting on the nozzle vane 7A under a pressure condition of the upper limit value PU of the pressure. The load VL4 acts in the same direction as the load VL3, and the direction of action is not reversed. In this way, the nozzle vane 7 (7A) near the tongue differs from the nozzle vane 8 (8B) far from the tongue in that there is a case where the direction of action of the load acting on the nozzle vane 7 near the tongue is reversed due to a pressure variation in the exhaust gas flow path 40 in one pulsation cycle of the internal combustion engine 10. In the short term of one pulsation cycle of the internal combustion engine 10, in the case where the direction of action of the load acting on the nozzle vane 6 is reversed, there is a case where the risk of wear occurring on the vane shaft 53 fixed to the nozzle vane 6 becomes high.

[0101] (notch portion)

[0102] As a result of the intensive study by the present inventors and others, it was found that, due to a pressure variation in the exhaust gas flow path 40 in one pulsation cycle of the internal combustion engine 10, the load acting on the leading edge side or the trailing edge side of the nozzle vane 7 near the tongue greatly varies, and the variation of the load of the leading edge side and the trailing edge side becomes one of the causes of the reversal of the direction of action of the load acting on the nozzle vane 7 near the tongue.

[0103] Figures 9-11 are drawings each showing a negative pressure surface of a nozzle vane near a tongue according to an embodiment.

[0104] As Figure 2 shown, the variable displacement turbine 2 (2A) of some embodiments is provided with the turbine rotor 21 described above, the scroll flow path forming portion 26 forming the scroll flow path 25 described above, the exhaust gas flow path forming portion 4 forming the exhaust gas flow path 40 described above, and the variable nozzle unit 5 including the plurality of nozzle vanes 6 and the rotation mechanism portion 51 described above. As Figure 4 shown, the plurality of nozzle vanes 6 includes at least one nozzle vane 7 located in the vicinity of the tongue and at least one nozzle vane 8 located far from the tongue. As Figures 9-11 shown, at least one nozzle vane 7 near the tongue in the variable displacement turbine 2 (2A) has a notch portion 75 cut larger than a notch portion 85 cut in at least one of a leading edge end 81 or a trailing edge end 82 of a nozzle vane 8 far from the tongue.

[0105] In Figure 9In the illustrated embodiment, all of the tongue-near nozzle vanes 7 located in the tongue-near region 40A have a cutout portion 75, i.e., a leading edge side cutout portion 76, formed at the leading edge end 71 and a cutout portion 75, i.e., a trailing edge side cutout portion 77, formed at the trailing edge end 72.

[0106] In Figure 10 In the illustrated embodiment, all of the tongue-near nozzle vanes 7 located in the tongue-near region 40A have a trailing edge side cutout portion 77, and no cutout portion 75 (leading edge side cutout portion 76) is formed at the leading edge end 71. In the case where the negative pressure surface 70B is made positive as shown in the plan view, the leading edge end 71 extends in a straight line from the hub side end 73 to the shroud side end 74 in the direction along which the rotational center RC extends. Figure 10

[0107] In Figure 11 In the illustrated embodiment, all of the tongue-near nozzle vanes 7 located in the tongue-near region 40A have a leading edge side cutout portion 76, and no cutout portion 75 (trailing edge side cutout portion 77) is formed at the trailing edge end 72. In the case where the negative pressure surface 70B is made positive as shown in the plan view, the trailing edge end 72 extends in a straight line from the hub side end 73 to the shroud side end 74 in the direction along which the rotational center RC extends. Figure 11

[0108] Figure 12 FIG. 6 is a view showing a negative pressure surface of a tongue-far nozzle vane according to an embodiment.

[0109] As shown in FIG. 6, all of the tongue-far nozzle vanes 8 located in the tongue-far region 40B can have no cutout portion 85 formed at both the leading edge end 81 and the trailing edge end 82. Alternatively, at least one of the tongue-far nozzle vanes 8 located in the tongue-far region 40B can have at least one of a cutout portion 85, i.e., a leading edge side cutout portion 86, formed at the leading edge end 81 or a cutout portion 85, i.e., a trailing edge side cutout portion 87, formed at the trailing edge end 82. Figure 8 Figure 12 Figure 12 In the illustrated embodiment, at least one of the tongue-far nozzle vanes 8 has both the leading edge side cutout portion 86 and the trailing edge side cutout portion 87.

[0110] In Figure 12 In the illustrated embodiment, the cutout portion 75 of the tongue-near nozzle vane 7 is larger than the cutout portion 85 of the tongue-far nozzle vane 8. As shown in FIG. 7, the leading edge side cutout portion 76 of the tongue-near nozzle vane 7 is larger than the leading edge side cutout portion 86 of the tongue-far nozzle vane 8. The trailing edge side cutout portion 77 of the tongue-near nozzle vane 7 is larger than the trailing edge side cutout portion 87 of the tongue-far nozzle vane 8. Figure 12

[0111] ​​​​​Note that the size of the trailing edge side cutout portion 77, 87 can also be determined by the following method: in a plan view in which the negative pressure surface 60B is made the front surface as shown in FIG. 8, the area Fl is determined by comparing the sum of the lengths in the blade length direction from a straight line LRl that passes through the trailing edge end 62 of the longest distance from the center of rotation RC and is parallel to the center of rotation RC. Figure 12

[0112] In addition, the size of the leading edge side cutout portion 76, 86 can also be determined by the following method: in a plan view in which the negative pressure surface 60B is made the front surface as shown in FIG. 8, the area F2 is determined by comparing the sum of the lengths in the blade length direction from a straight line LR2 that passes through the leading edge end 61 of the longest distance from the center of rotation RC and is parallel to the center of rotation RC. Note that the size of the leading edge side cutout portion 76, 86 and the trailing edge side cutout portion 77, 87 can also be determined by comparing the area F2 and the area Fl. Figure 12

[0113] Figure 13 is a diagram for explaining the load evaluation results of the nozzle vane in the vicinity of the tongue portion shown in FIG. 7. In Figure 9 , the load VL applied to the nozzle vane is evaluated in a ratio in which the maximum load in a certain direction of action (positive direction) is made 100%. The load VL5 applied to the nozzle vane 7 (7A) in the vicinity of the tongue portion having the cutout portion 75 under the pressure condition of the lower limit value PL of the pressure described above and the load VL6 applied to the nozzle vane 7 (7A) under the pressure condition of the upper limit value PU of the pressure described above are shown. The load VL6 acts in the same direction as the load VL5, and the direction of action is not reversed. By thus providing the cutout portion 75 on the nozzle vane 7 (7A) in the vicinity of the tongue portion, the portion acted on by the fluid force from the exhaust gas flowing in the exhaust gas flow path 40 can be selectively removed. Thus, the reversal of the direction of action of the load applied to the nozzle vane 7 in the vicinity of the tongue portion can be suppressed. Figure 13 According to the above-described structure, by providing the cutout portion 75 in at least one of the leading edge end 71 or the trailing edge end 72 of the nozzle vane 7 in the vicinity of the tongue portion, the portion acted on by the fluid force from the exhaust gas flowing in the exhaust gas flow path 40 can be selectively removed, and the reversal of the direction of action of the load applied to the nozzle vane 7 in the vicinity of the tongue portion can be suppressed. By suppressing the reversal of the direction of action of the load applied to the nozzle vane 7 in the vicinity of the tongue portion, the number of times of collision of the vane shaft 53 fixed to the nozzle vane 7 in the vicinity of the tongue portion with other components (the nozzle seat 41) can be reduced, and thus the wear of the vane shaft 53 described above can be suppressed.

[0114]

[0115] ​​​(rear edge side cutout portion)

[0116] In some embodiments, as shown in Figure 9 , Figure 10 With regard to the above-described rear edge side cutout portion 77, when a blade length position PS of the leading edge end 71 in the blade length direction WS of the nozzle vane 7 near the tongue portion from the leading edge end 71 toward the rear edge end 72 is set to 0% and a blade length position PS of the rear edge end 72 in the blade length direction WS is set to 100%, at least a portion of the rear edge side cutout portion is formed in a region Al in which the blade length position PS is included in a range of 75% or more and 100% or less.

[0117] With regard to the above-described region Al, it is preferable that the blade length position PS be included in a range of 75% or more and 90% or less, and more preferable that the blade length position PS be included in a range of 75% or more and 80% or less. In other words, it is preferable that the rear edge side cutout portion 77 be formed in a range in which the blade length position PS is 90% or less, and more preferable that the rear edge side cutout portion 77 be formed in a range in which the blade length position PS is 80% or less. In the embodiment shown in Figure 9 , Figure 10 In the embodiment shown in

[0118] According to the above-described structure, the load on the rear edge side (a range in which the blade length position is 75% or more and 100% or less) of the nozzle vane 7 near the tongue portion greatly changes due to the pressure variation in the exhaust gas flow path 40 in one pulsation cycle of the internal combustion engine 10, and the change in the load on the above-described rear edge side becomes one of the reasons for the reversal of the acting direction of the load acting on the nozzle vane 7 near the tongue portion. Therefore, by forming at least a portion of the rear edge side cutout portion 77 in the region Al in which the blade length position is included in a range of 75% or more and 100% or less on the rear edge side of the nozzle vane 7 near the tongue portion, the reversal of the acting direction of the load acting on the nozzle vane 7 near the tongue portion can be effectively suppressed.

[0119] In some embodiments, as shown in Figure 9 , Figure 10 With regard to the above-described rear edge side cutout portion 77, when a blade height position PH of the hub side end 73 in the blade height direction WH of the nozzle vane 7 near the tongue portion from the hub side end 73 toward the shroud side end 74 is set to 0% and a blade height position PH of the shroud side end 74 in the blade height direction WH is set to 100%, at least a portion of the rear edge side cutout portion is formed in a region Al in which the blade height position PH is included in a range of 15% or more and 85% or less.

[0120] The above-described region Al is preferably included in a range in which the blade height position PH is from 40% to 60% in the region Al, and more preferably included in a range in which the blade height position PH is from 20% to 80% in the region Al. In the embodiment shown in Figure 9 , Figure 10In the illustrated embodiment, at least a portion of the trailing edge side cutout portion 77 is formed in a region A11 in which the blade length position PS is in the range of 75 to 100% and the blade height position PH is in the range of 15 to 85%.

[0121] According to the above-described structure, the load on the trailing edge side height central portion (region in which the blade height position is in the range of 15% or more to 85% or less) of the tongue portion vicinity nozzle vane 7 varies greatly due to the pressure variation in the exhaust gas flow path 40 during one pulsation cycle of the internal combustion engine 10, and the variation in the load on the trailing edge side height central portion becomes one of the reasons for the reversal of the acting direction of the load acting on the tongue portion vicinity nozzle vane 7. Therefore, by forming at least a portion of the trailing edge side cutout portion 77 in the trailing edge side height central portion of the tongue portion vicinity nozzle vane 7, that is, in the region A11 in which the blade height position is in the range of 15% or more to 85% or less, the reversal of the acting direction of the load acting on the tongue portion vicinity nozzle vane 7 can be effectively suppressed.

[0122] (front edge side cutout portion)

[0123] In some embodiments, as Figure 9 , Figure 11 illustrated, at least a portion of the above-described front edge side cutout portion 76 is formed in a region A2 in which the blade length position PS is in the range of 0% or more to 25% or less.

[0124] In the case of the above-described region A2, it is preferable that the blade length position PS be in the range of 10% or more to 25% or less, and more preferably, the blade length position PS be in the range of 20% or more to 25% or less. In other words, it is preferable that the front edge side cutout portion 76 be formed in a range in which the blade length position PS is 10% or more, and more preferably, in a range in which the blade length position PS is 20% or more. Figure 9 , Figure 11 In the illustrated embodiment, at least a portion of the front edge side cutout portion 76 is formed in a range in which the blade length position PS is 0% to 25%.

[0125] According to the above-described structure, the load on the front edge side (region in which the blade length position is in the range of 0% or more to 25% or less) of the tongue portion vicinity nozzle vane 7 varies greatly due to the pressure variation in the exhaust gas flow path 40 during one pulsation cycle of the internal combustion engine 10, and the variation in the load on the front edge side becomes one of the reasons for the reversal of the acting direction of the load acting on the tongue portion vicinity nozzle vane 7. Therefore, by forming at least a portion of the front edge side cutout portion 76 in the front edge side of the tongue portion vicinity nozzle vane 7, that is, in the region A2 in which the blade length position is in the range of 0% or more to 25% or less, the reversal of the acting direction of the load acting on the tongue portion vicinity nozzle vane 7 can be effectively suppressed.

[0126] In some embodiments, as Figure 9 , Figure 11As shown, at least a portion of the aforementioned leading edge lateral cut 76 is formed in region A21 of region A2, where the leaf height position PH is in the range of 15% to 85%.

[0127] The aforementioned region A21 preferably includes the region A2 where the pH at the upper leaf position ranges from 40% to 60%, and more preferably includes the region A2 where the pH at the upper leaf position ranges from 20% to 80%. Figure 9 , Figure 11 In the embodiment shown, at least a portion of the leading edge lateral cut 76 is formed in the range of 0% to 25% of the leaf length position PS and 15% to 85% of the leaf height position PH.

[0128] According to the above structure, the load on the central portion of the height of the nozzle blade 7 near the leading edge (within the range of 15% to 85% of the blade height) changes significantly due to pressure variations within the exhaust gas path 40 during one pulse cycle of the internal combustion engine 10. This change in load on the central portion of the height of the leading edge is one of the reasons for the reversal of the load direction acting on the nozzle blade 7 near the tongue. Therefore, by forming at least a portion of the leading edge cutout 76 in the central portion of the height of the nozzle blade 7 near the leading edge, i.e., the region A21 containing the blade height within the range of 15% to 85%, the reversal of the load direction acting on the nozzle blade 7 near the tongue can be effectively suppressed.

[0129] (The size relationship between the anterior and posterior lateral incisions)

[0130] In some implementations, such as Figure 9 As shown, at least one nozzle blade 7 near the tongue of the variable capacity turbine 2 (2A) described above is configured such that the leading edge side cutout 76 and the trailing edge side cutout 77 are of the same size. In one embodiment, the area F2 of the leading edge side cutout 76 and the area F1 of the trailing edge side cutout 77 are the same.

[0131] In the illustrated embodiment, the leading edge side cutout 76 and the trailing edge side cutout 77 are configured to... Figure 9 The diagram shows the negative pressure surface 60B as the front view, which is symmetrical with respect to the imaginary line LV that satisfies the condition that the blade length position PS is 50%.

[0132] According to the above-described structure, in the variable displacement turbo 2, the fluid flowing from the upstream side of the nozzle vane 6 into the high-speed flow receives a fluid force from the surrounding fluid. Therefore, in order to maintain the nozzle vane 6 at a prescribed angle, it is desirable to reduce the torque around the rotation center RC that is applied to the nozzle vane 6. By making the size of the leading edge side cutout portion 76 and the trailing edge side cutout portion 77 of the nozzle vane near the tongue portion the same, the fluid force applied to the leading edge side and the trailing edge side of the nozzle vane 7 near the tongue portion can be made equal, and therefore, the torque around the rotation center RC that is applied to the nozzle vane near the tongue portion can be reduced. Note that the rotation center RC can be located on the leading edge side of the imaginary line LV, or on the trailing edge side of the imaginary line LV.

[0133] Figure 14 FIG. 6 is a view showing the negative pressure surface of the nozzle vane near the tongue portion according to an embodiment.

[0134] In some embodiments, as shown in Figure 14 , at least one nozzle vane 7 near the tongue portion of the above-described variable displacement turbo 2 (2A) is configured so that the size of the trailing edge side cutout portion 77 is larger than the size of the leading edge side cutout portion 76. In some embodiments, the area Fl of the trailing edge side cutout portion 77 is larger than the area F2 of the leading edge side cutout portion 76.

[0135] According to the above-described structure, the trailing edge side cutout portion 77 has a greater inhibitory effect than the leading edge side cutout portion 76 on the reversal of the direction of the load acting on the nozzle vane 7 near the tongue portion. Therefore, by making the trailing edge side cutout portion 77 of the nozzle vane 7 near the tongue portion larger than the leading edge side cutout portion 76, the nozzle vane 7 near the tongue portion can effectively inhibit the reversal of the direction of the load acting on the nozzle vane 7 near the tongue portion.

[0136] Figure 15 and Figure 16 are views showing the negative pressure surface of the nozzle vane near the tongue portion according to an embodiment.

[0137] In some embodiments, as shown in Figure 9 , Figure 11 , the above-described leading edge side cutout portion 76 is not formed in a range where the blade height position PH is 0% or more and less than 15% or a range where it is more than 85% and 100% or less. The leading edge end 71 has a hub side edge 711 that extends from the hub side end of the leading edge side cutout portion 76 in a direction opposite the blade height direction WH, and a shroud side edge 712 that extends from the shroud side end of the leading edge side cutout portion 76 in the blade height direction WH, as shown in Figure 9 , Figure 11 . The hub side edge 711 is connected to the hub side end 73, and the shroud side edge 712 is connected to the shroud side end 74.

[0138] In some embodiments, as shown in Figure 9, Figure 10 As shown, the aforementioned trailing edge lateral cut 77 is not formed in the range where the pH at the leaf height is 0% or higher and lower than 15%, or in the range where the pH is higher than 85% and lower than 100%. The trailing edge end 72 has, as shown... Figure 9 , Figure 10 The diagram shows a hub side 721 extending from the hub side end of the trailing edge side cutout 77 in a direction opposite to the blade height direction WH, with the negative pressure surface 60B shown as the front view, and a shroud side 722 extending from the shroud side end of the trailing edge side cutout 77 in the blade height direction WH. The hub side 721 is connected to the hub side end 73, and the shroud side 722 is connected to the shroud side end 74.

[0139] It should be noted that, regarding the anterior edge lateral incision 76 and the posterior edge lateral incision 77, as... Figure 15 , Figure 16 As shown, it can be at least partially formed in the area where the pH at leaf height is above 0% and below 15%, or at least partially formed in the area where the pH at leaf height is above 85% and below 100%. Additionally, as... Figure 16 As shown, it can also be formed at least in the range where the leaf length position PS exceeds 25% and is less than 75%.

[0140] (The size of the nozzle blade height)

[0141] Figures 17-19 These are diagrams showing the negative pressure surface of the nozzle blades near the tongue in one embodiment.

[0142] like Figure 2 As shown, some embodiments of the variable capacity turbine 2 (2B) include the turbine rotor 21 described above, the vortex flow path forming section 26 forming the vortex flow path 25 described above, the exhaust flow path forming section 4 forming the exhaust flow path 40 described above, and the variable nozzle unit 5 including the plurality of nozzle blades 6 and the rotation mechanism section 51 described above. Figures 17-19 As shown, the plurality of nozzle blades 6 include at least one tongue-near nozzle blade 7 located in the tongue-near region 40A and at least one tongue-farward nozzle blade 8 located in the tongue-farward region 40B. For at least one tongue-near nozzle blade 7 in the variable capacity turbine 2 (2B), as Figures 17-19 As shown, the maximum length MH1 of the nozzle blade 7 near the tongue in the blade height direction from the hub side end 73 to the shield side end 74 is shorter than the maximum length MH2 of the nozzle blade 8 far from the tongue in the blade height direction.

[0143] exist Figure 17In each of the drawings, the hub side end 83 of the tongue far nozzle blade 8 is set to 0% in the hub height position PH in the hub height direction WH from the hub side end 83 toward the shroud side end 84, and the shroud side end 84 is set to 100% in the hub height position PH in the hub height direction WH.

[0144] In Figure 18 In the embodiment shown, the tongue near nozzle blade 7 is reduced in blade height on the shroud side relative to the tongue far nozzle blade 8. The tongue near nozzle blade 7 is configured so that the hub height position PH of the shroud side end 74 is 90% or less, and the gap G2 between the shroud side end 74 and the shroud side flow path surface 47 is larger than that of the tongue far nozzle blade 8.

[0145] In Figure 19 In the embodiment shown, the tongue near nozzle blade 7 is reduced in blade height on the hub side relative to the tongue far nozzle blade 8. The tongue near nozzle blade 7 is configured so that the hub height position PH of the hub side end 73 is 10% or more, and the gap Gl between the hub side end 73 and the hub side flow path surface 44 is larger than that of the tongue far nozzle blade 8.

[0146] In Figure 20 In the embodiment shown, the tongue near nozzle blade 7 is reduced in blade height on the hub side and the shroud side relative to the tongue far nozzle blade 8. The tongue near nozzle blade 7 is configured so that the hub height position PH of the shroud side end 74 is 95% or less, and the hub height position PH of the hub side end 73 is 5% or more, and the above-mentioned gaps Gl and G2 are larger than those of the tongue far nozzle blade 8.

[0147] Figure 17 is a diagram for explaining Figure 20 is a diagram for explaining the load evaluation results of the tongue near nozzle blade. In Figures 17-19 In the tongue near nozzle blade 7 (7A) in which the maximum length MH1 is shorter than the maximum length MH2, the load VL7 under the pressure condition of the above-mentioned pressure lower limit value PL and the load VL8 under the pressure condition of the above-mentioned pressure upper limit value PU are shown. In addition, the load VL1 of the tongue near nozzle blade 7 (7A) in which the maximum length MH1 and the maximum length MH2 are the same under the pressure condition of the above-mentioned pressure lower limit value PL and the load VL2 of the nozzle blade 7 (7A) in which the maximum length MH1 and the maximum length MH2 are the same under the pressure condition of the above-mentioned pressure upper limit value PU are shown. The variation ΔVL2 in the load between the load VL7 and the load VL8 is reduced compared to the variation ΔVL1 in the load between the load VL1 and the load VL2.

[0148] According to the above-described structure, the fluid force due to the secondary flow is applied to the shroud side and the hub side of the nozzle vane 6. The fluid force varies with the pressure variation of the variable displacement turbine 2. By making the maximum length MH1 in the blade height direction of the tongue vicinity nozzle vane 7 shorter than the maximum length MH2 in the blade height direction of the tongue distant nozzle vane 8, the area of the shroud side or the hub side of the tongue vicinity nozzle vane 7 (i.e., the gap G1 or G2 described above is increased), and thus, the fluid force due to the secondary flow acting on the tongue vicinity nozzle vane 7 can be reduced. Therefore, by making the maximum length MH1 in the blade height direction of the tongue vicinity nozzle vane 7 shorter than the maximum length MH2 in the blade height direction of the tongue distant nozzle vane 8, the variation amount of the load acting on the tongue vicinity nozzle vane 7 can be reduced in one pulsation cycle of the internal combustion engine 10, compared with the case where the maximum lengths MH1, MH2 in the blade height direction of the tongue vicinity nozzle vane 7 and the tongue distant nozzle vane 8 are the same. By reducing the variation amount of the load acting on the tongue vicinity nozzle vane 7, the wear of the vane shaft 53 fixed to the tongue vicinity nozzle vane 7 can be suppressed, and thus, the reliability and durability of the variable displacement turbine 2 can be improved.

[0149] In some embodiments, as shown in FIG. 7, the at least one tongue vicinity nozzle vane 7 has a maximum length MH1 in the blade height direction WH that is shorter than a maximum length MH2 in the blade height direction WH of the tongue distant nozzle vane 8. Figure 21 As shown in FIG. 7, when the maximum length MH2 in the blade height direction WH of the tongue distant nozzle vane 8 from the hub side end 83 toward the shroud side end 84 is set to 100%, the at least one tongue vicinity nozzle vane 7 described above is configured such that the maximum length MH1 in the blade height direction WH of the tongue vicinity nozzle vane 7 is a length of 90% or less.

[0150] According to the above-described structure, by making the maximum length MH1 in the blade height direction WH of the tongue vicinity nozzle vane 7 a length of 90% or less relative to the maximum length MH2 in the blade height direction WH of the tongue distant nozzle vane 8, the area of the shroud side or the hub side of the tongue vicinity nozzle vane 7 (i.e., the gap G1 or G2 described above is increased), and thus, the fluid force due to the secondary flow acting on the tongue vicinity nozzle vane 7 can be effectively reduced, and the variation amount of the load acting on the tongue vicinity nozzle vane 7 can be effectively reduced in one pulsation cycle of the internal combustion engine 10. As a result, the wear of the vane shaft 53 fixed to the tongue vicinity nozzle vane 7 can be effectively suppressed.

[0151] Figure 21 FIG. 8 is a view showing a negative pressure surface of a tongue vicinity nozzle vane according to an embodiment.

[0152] In some embodiments, as shown in FIG. 7, the at least one tongue vicinity nozzle vane 7 has a maximum length MH1 in the blade height direction WH that is shorter than a maximum length MH2 in the blade height direction WH of the tongue distant nozzle vane 8. Figure 4 As shown in FIG. 7, when the maximum length MH2 in the blade height direction WH of the tongue distant nozzle vane 8 from the hub side end 83 toward the shroud side end 84 is set to 100%, the at least one tongue vicinity nozzle vane 7 described above is configured such that the maximum length MH1 in the blade height direction WH of the tongue vicinity nozzle vane 7 is a length of 90% or less.

[0153] According to the above-described structure, the fluid force due to the secondary flow is applied to the shroud side and the hub side of the nozzle vane 6. The fluid force varies with the pressure variation of the variable capacity turbine 2. By making the maximum length MH1 in the vane height direction of the nozzle vane 7 near the tongue shorter than the nozzle vane 8 far from the tongue, the shroud side or the hub side of the nozzle vane 7 near the tongue can be reduced, and thus, the fluid force due to the secondary flow acting on the nozzle vane 7 near the tongue can be reduced. By reducing the above-described fluid force due to the secondary flow, the variation amount of the load acting on the nozzle vane 7 near the tongue in one pulsation cycle of the internal combustion engine 10 can be reduced. By thus reducing the variation amount of the load acting on the nozzle vane 7 near the tongue, the wear of the vane shaft 53 fixed to the nozzle vane 7 near the tongue having the above-described notch portion 75 can be effectively suppressed.

[0154] In some embodiments, as shown in FIG. 10, the tongue vicinity region 40A satisfies the condition of -90° ≤ α ≤ 90° with respect to the angular position around the scroll center in the scroll flow passage 25. It is preferable that the tongue vicinity region 40A satisfy the condition of -60° ≤ α ≤ 60°. It is more preferable that the condition of -45° ≤ α ≤ 45° be satisfied. Note that whether the nozzle vane 6 is located in the tongue vicinity region 40A can be determined by whether the rotation center RC of the nozzle vane 6 is located in the tongue vicinity region 40A. Figure 2 According to the above-described structure, the tongue vicinity region 40A in which the above-described angular position α satisfies the condition of -90° ≤ α ≤ 90° is likely to have the direction of the load acting on the nozzle vane 6 in the region reversed due to the pressure variation in one pulsation cycle of the internal combustion engine 10, and thus, the wear of the nozzle vane 6 in the region is likely to occur. By providing the above-described notch portion 75 or shortening the maximum length MH1 in the vane height direction WH in the nozzle vane 6 located in the tongue vicinity region 40A satisfying the above-described condition, the wear of the vane shaft 53 fixed to the nozzle vane 7 near the tongue can be effectively suppressed.

[0155] As shown in FIG. 10, some embodiments of the supercharger 1 include the above-described variable capacity turbine 2 (2A, 2B) and the above-described centrifugal compressor 3 configured to be driven by the variable capacity turbine 2 (2A, 2B).

[0156] ​ As shown in FIG. 10, some embodiments of the supercharger 1 include the above-described variable capacity turbine 2 (2A, 2B) and the above-described centrifugal compressor 3 configured to be driven by the variable capacity turbine 2 (2A, 2B).

[0157] ​According to the above-described structure, since the wear of the blade shaft 53 fixed to the nozzle vane 7 in the vicinity of the tongue portion can be suppressed, the reliability and durability of the variable displacement turbo 2 and the supercharger 1 provided with the variable displacement turbo 2 can be improved. Note that, by providing the above-described notch portion 75 on the nozzle vane 7 in the vicinity of the tongue portion or shortening the maximum length MH1 in the vane height direction WH, the effect of the variable displacement turbo 2 is not significantly reduced.

[0158] The present disclosure is not limited to the above-described embodiments, and includes modes in which the above-described embodiments are modified and modes in which these modes are appropriately combined.

[0159] The content described in the above-described embodiments can be grasped, for example, as follows.

[0160] 1) At least one embodiment of the present disclosure relates to a variable displacement turbo (2, 2A) provided with:

[0161] a turbo rotor (21);

[0162] a scroll flow path forming portion (26) that forms a scroll flow path (25) on the outer peripheral side of the above-described turbo rotor (21);

[0163] an exhaust gas flow path forming portion (4) that forms an exhaust gas flow path (40) for guiding exhaust gas from the above-described scroll flow path (25) to the above-described turbo rotor (21);

[0164] a variable nozzle unit (5) for adjusting the flow of the above-described exhaust gas in the above-described exhaust gas flow path (40),

[0165] the above-described variable nozzle unit (5) includes:

[0166] a plurality of nozzle vanes (6) that are arranged at intervals along the circumferential direction of the above-described turbo rotor (21) in the above-described exhaust gas flow path (40);

[0167] a rotation mechanism portion (51) configured to rotate the above-described plurality of nozzle vanes (6) around respective rotation centers (RC),

[0168] when the above-described exhaust gas flow path (40) is divided into a tongue portion vicinity region (40A) located in the vicinity of a tongue portion (29) of the above-described scroll flow path (25) and a region other than the above-described tongue portion vicinity region (40A), that is, a tongue portion far region (40B), the above-described plurality of nozzle vanes (6) include at least one tongue portion vicinity nozzle vane (7) located in the above-described tongue portion vicinity region (40A) and at least one tongue portion far nozzle vane (8) located in the above-described tongue portion far region (40B),

[0169] The at least one tongue vicinity nozzle vane (7) has a cutout portion (75) that is cut larger than a cutout portion (81) of a leading edge end (81) or a trailing edge end (82) of a tongue distant nozzle vane (8) at least one of a leading edge end (71) or a trailing edge end (72) of the tongue vicinity nozzle vane (7).

[0170] The present inventors have found that the load acting on the leading edge side or the trailing edge side of the tongue vicinity nozzle vane (7) due to the pressure variation in the exhaust gas flow path (40) in one pulsation cycle of the internal combustion engine (10) greatly varies, and the variation in the load of the leading edge side or the trailing edge side is one of the causes of the reversal of the acting direction of the load acting on the tongue vicinity nozzle vane (7).

[0171] According to the structure of 1) above, by providing the cutout portion (75) at least one of the leading edge end (71) or the trailing edge end (72) of the tongue vicinity nozzle vane (7), the portion on which the fluid force from the exhaust gas flowing in the exhaust gas flow path (40) acts can be selectively removed, and the reversal of the acting direction of the load acting on the tongue vicinity nozzle vane (7) can be suppressed. By suppressing the reversal of the acting direction of the load acting on the tongue vicinity nozzle vane (7), the number of times of collision of the vane shaft (53) fixed to the tongue vicinity nozzle vane (7) and other components can be reduced, and thus, the wear of the vane shaft (53) can be suppressed.

[0172] 2) In some embodiments, the variable displacement turbo (2, 2A) according to 1) above, wherein,

[0173] The at least one tongue vicinity nozzle vane (7) has a trailing edge side cutout portion (77) that is the cutout portion (75) of the trailing edge end (72) of the tongue vicinity nozzle vane (7),

[0174] The trailing edge side cutout portion (77) is formed at least in a region (A1) in which the blade length position is 75% or more and 100% or less, when the blade length position of the leading edge end (71) of the tongue vicinity nozzle vane (7) from the leading edge end (71) toward the trailing edge end (72) is set to 0%, and the blade length position of the trailing edge end (72) in the blade length direction is set to 100%.

[0175] According to the structure of the above 2), the load of the trailing edge side (range of 75% or more and 100% or less in blade length position) of the tongue vicinity nozzle vane (7) greatly changes due to the pressure variation in the exhaust gas flow path (40) in one pulsation cycle of the internal combustion engine (10), and the change in the load of the trailing edge side becomes one of the reasons for the reversal of the acting direction of the load acting on the tongue vicinity nozzle vane (7). Therefore, by forming at least a part of the trailing edge side cutout portion (77) in the trailing edge side of the tongue vicinity nozzle vane (7), that is, in the region (A1) in which the blade length position is included in the range of 75% or more and 100% or less, the reversal of the acting direction of the load acting on the tongue vicinity nozzle vane (7) can be effectively suppressed.

[0176] 3) In some embodiments, the variable displacement turbo (2, 2A) according to the above 2), wherein

[0177] The trailing edge side cutout portion (77) is formed at least in part in the region (A11) in which the blade height position is included in the range of 15% or more and 85% or less when the blade height position of the hub side end (73) of the tongue vicinity nozzle vane (7) from the hub side end (73) toward the shroud side end (74) is set to 0% and the blade height position of the shroud side end (74) in the blade height direction is set to 100%.

[0178] According to the structure of the above 3), the height central portion (range of 15% or more and 85% or less in blade height position) of the trailing edge side of the tongue vicinity nozzle vane (7) greatly changes in load due to the pressure variation in the exhaust gas flow path (40) in one pulsation cycle of the internal combustion engine (10), and the change in the load of the height central portion of the trailing edge side becomes one of the reasons for the reversal of the acting direction of the load acting on the tongue vicinity nozzle vane (7). Therefore, by forming at least a part of the trailing edge side cutout portion (77) in the height central portion of the trailing edge side of the tongue vicinity nozzle vane (7), that is, in the region (A11) in which the blade height position is included in the range of 15% or more and 85% or less, the reversal of the acting direction of the load acting on the tongue vicinity nozzle vane (7) can be effectively suppressed.

[0179] 4) In some embodiments, the variable displacement turbo (2, 2A) according to the above 2) or 3), wherein

[0180] The above at least one tongue vicinity nozzle vane (7) has the cutout portion (75) formed at the leading edge end (71) of the above tongue vicinity nozzle vane (7), that is, the leading edge side cutout portion (76),

[0181] At least a part of the above leading edge side cutout portion (76) is formed in the region (A2) in which the above blade length position is included in the range of 0% or more and 25% or less.

[0182] According to the structure of the above 4), the load of the leading edge side (range of 0% or more and 25% or less in blade length position) of the tongue vicinity nozzle vane (7) greatly changes due to the pressure variation in the exhaust gas flow path (40) in one pulsation cycle of the internal combustion engine (10), and the change in the load of the above leading edge side becomes one of the reasons for the reversal of the acting direction of the load acting on the tongue vicinity nozzle vane (7). Therefore, by forming at least a part of the leading edge side cutout portion (76) in the leading edge side of the tongue vicinity nozzle vane (7), that is, in the region (A2) in which the blade length position is included in the range of 0% or more and 25% or less, the reversal of the acting direction of the load acting on the tongue vicinity nozzle vane (7) can be effectively suppressed.

[0183] 5) In some embodiments, the variable displacement turbo (2, 2A) according to the above 4), wherein,

[0184] For the above leading edge side cutout portion (76), when the blade height position of the hub side end (73) of the above tongue vicinity nozzle vane (7) in the blade height direction from the hub side end (73) toward the shroud side end (74) is set to 0%, and the blade height position of the above shroud side end (74) in the above blade height direction is set to 100%, at least a part of the leading edge side cutout portion is formed in a region (A21) in which the blade height position is included in the range of 15% or more and 85% or less.

[0185] According to the structure of the above 5), the height central portion (range of 15% or more and 85% or less in blade height position) of the leading edge side of the tongue vicinity nozzle vane (7) greatly changes due to the pressure variation in the exhaust gas flow path (40) in one pulsation cycle of the internal combustion engine (10), and the change in the load of the above height central portion of the leading edge side becomes one of the reasons for the reversal of the acting direction of the load acting on the tongue vicinity nozzle vane (7). Therefore, by forming at least a part of the leading edge side cutout portion (76) in the height central portion of the leading edge side of the tongue vicinity nozzle vane (7), that is, in the region (A21) in which the blade height position is included in the range of 15% or more and 85% or less, the reversal of the acting direction of the load acting on the tongue vicinity nozzle vane (7) can be effectively suppressed.

[0186] 6) In some embodiments, the variable displacement turbo (2, 2A) according to the above 4) or 5), wherein,

[0187] The above at least one tongue vicinity nozzle vane (7) is configured such that the size of the above leading edge side cutout portion (76) and the above trailing edge side cutout portion (77) is the same.

[0188] According to the structure of the above 6), in the variable displacement turbo (2), the fluid of the high speed flow flowing from the upstream side of the nozzle vane (6) receives the fluid force by the surrounding fluid. Therefore, in order to maintain the nozzle vane (6) at a prescribed angle, it is desirable that the torque around the rotation center (RC) applied to the nozzle vane (6) is small. By making the size of the leading edge side cutout portion (76) and the trailing edge side cutout portion (77) of the nozzle vane near the tongue portion the same, the fluid force applied to the leading edge side and the trailing edge side of the nozzle vane (7) near the tongue portion can be made equal, and therefore, the torque around the rotation center (RC) applied to the nozzle vane near the tongue portion can be reduced.

[0189] 7) In some embodiments, the variable displacement turbo (2, 2A) according to any one of the above 4) or 5), wherein,

[0190] The at least one nozzle vane (7) near the tongue portion is configured such that the size of the trailing edge side cutout portion (77) is larger than the size of the leading edge side cutout portion (76).

[0191] According to the structure of the above 7), the trailing edge side cutout portion (77) has a good effect of suppressing the reversal of the direction of the load acting on the nozzle vane (7) near the tongue portion compared to the leading edge side cutout portion (76). Therefore, by making the trailing edge side cutout portion (77) of the nozzle vane (7) near the tongue portion larger than the leading edge side cutout portion (76), the reversal of the direction of the load acting on the nozzle vane (7) near the tongue portion can be effectively suppressed.

[0192] 8) In some embodiments, the variable displacement turbo (2, 2A) according to any one of the above 1) to 7), wherein,

[0193] The at least one nozzle vane (7) near the tongue portion has a maximum length (MH1) in the blade height direction from the hub side end (73) toward the shroud side end (74) that is shorter than the maximum length (MH2) in the blade height direction from the hub side end (73) toward the shroud side end (74) of the nozzle vane (8) far from the tongue portion.

[0194] According to the structure of the above 8), the fluid force due to the secondary flow is applied to the shroud side and the hub side of the nozzle vane (6). The fluid force varies with the pressure variation of the variable displacement turbo (2). By making the maximum length (MH1) in the blade height direction of the nozzle vane (7) near the tongue shorter than that of the nozzle vane (8) far from the tongue, the area of the shroud side or the hub side of the nozzle vane (7) near the tongue can be reduced, and thus the fluid force due to the secondary flow acting on the nozzle vane (7) near the tongue can be reduced. By reducing the above fluid force due to the secondary flow, the variation amount of the load acting on the nozzle vane (7) near the tongue in one pulsation cycle of the internal combustion engine (10) can be reduced. By thus reducing the variation amount of the load acting on the nozzle vane (7) near the tongue, the wear of the vane shaft (53) fixed to the nozzle vane (7) near the tongue having the above cutout portion (75) can be effectively suppressed.

[0195] 9) In some embodiments, the variable displacement turbo (2, 2A) according to the above 8), wherein

[0196] When the maximum length (MH2) in the blade height direction of the nozzle vane (8) far from the tongue from the hub side end (83) toward the shroud side end (84) is set to 100%, the above at least one nozzle vane (7) near the tongue is configured such that the above maximum length (MH1) in the blade height direction of the nozzle vane (7) near the tongue is a length of 90% or less.

[0197] According to the structure of the above 9), by setting the maximum length (MH1) in the blade height direction of the nozzle vane (7) near the tongue to a length of 90% or less with respect to the maximum length (MH2) in the blade height direction of the nozzle vane (8) far from the tongue, the area of the shroud side or the hub side of the nozzle vane (7) near the tongue can be reduced, and thus the fluid force due to the secondary flow acting on the nozzle vane (7) near the tongue can be effectively reduced, and the variation amount of the load acting on the nozzle vane (7) near the tongue in one pulsation cycle of the internal combustion engine (10) can be effectively reduced. Thus, the wear of the vane shaft (53) fixed to the nozzle vane (7) near the tongue can be effectively suppressed.

[0198] 10) In some embodiments, the variable displacement turbo (2) according to any one of the above 1) to the above 9), wherein

[0199] With respect to the angular position around the scroll center in the scroll flow passage (25), in a case where the angular position of the tongue (29) is set to 0°, and the angle is defined in a manner such that the angular position gradually increases from the tongue (29) toward the downstream side of the scroll flow passage (25), the above tongue vicinity region (40A) satisfies the condition of -90° ≤ α ≤ 90°.

[0200] The above tongue vicinity region (40A) satisfies the condition of -90° ≤ α ≤ 90°.

[0201] According to the structure of 10) above, the tongue vicinity region (40A) in which the angle position α satisfies the condition of -90° ≤ α ≤ 90° has a high possibility that the direction of action of the load acting on the nozzle vane (6) in the region due to the pressure variation in one pulsation cycle of the internal combustion engine (10) is reversed, and thus wear is generated on the nozzle vane (6) in the region. By providing the notch portion (75) on the nozzle vane (6) located in the tongue vicinity region (40A) satisfying the condition, wear of the vane shaft (53) fixed to the tongue vicinity nozzle vane (7) can be effectively suppressed.

[0202] 11) At least one embodiment of the present disclosure relates to a variable capacity turbo (2, 2B) including:

[0203] a turbo rotor (21);

[0204] a scroll flow path forming portion (26) that forms a scroll flow path (25) on an outer peripheral side of the turbo rotor (21);

[0205] an exhaust gas flow path forming portion (4) that forms an exhaust gas flow path (40) for guiding exhaust gas from the scroll flow path (25) toward the turbo rotor (21);

[0206] a variable nozzle unit (5) that adjusts a flow of the exhaust gas in the exhaust gas flow path (40),

[0207] the variable nozzle unit (5) includes:

[0208] a plurality of nozzle vanes (6) that are arranged at intervals along a circumferential direction of the turbo rotor (21) on the exhaust gas flow path (40);

[0209] a rotation mechanism portion (51) configured to rotate the plurality of nozzle vanes (6) around respective rotation centers (RC),

[0210] when the exhaust gas flow path (40) is divided into a tongue vicinity region (40A) located in the vicinity of a tongue (29) of the scroll flow path (25) and a tongue distant region (40B) other than the tongue vicinity region (40A), the plurality of nozzle vanes (6) include at least one tongue vicinity nozzle vane (7) located in the tongue vicinity region (40A) and at least one tongue distant nozzle vane (8) located in the tongue distant region (40B),

[0211] The maximum length (MH1) of the tongue-proximal nozzle vane (7) in the blade height direction from the hub side end (73) toward the shroud side end (74) is shorter than that of the tongue-distal nozzle vane (8).

[0212] According to the structure of the above 11), the fluid force due to the secondary flow is applied to the shroud side and hub side regions of the nozzle vane (6). This fluid force varies with the pressure variation of the variable displacement turbo (2). By making the maximum length in the blade height direction of the tongue-proximal nozzle vane (7) shorter than that of the tongue-distal nozzle vane (8), the shroud side and hub side regions of the tongue-proximal nozzle vane (7) can be reduced, and thus the above fluid force due to the secondary flow acting on the tongue-proximal nozzle vane (7) can be reduced. Therefore, by making the maximum length (MH1) in the blade height direction of the tongue-proximal nozzle vane (7) shorter than that of the tongue-distal nozzle vane (8), the variation amount of the load acting on the tongue-proximal nozzle vane (7) can be reduced in one pulsation cycle of the internal combustion engine (10) compared to the case where the maximum lengths (MH1, MH2) in the blade height direction of the tongue-proximal nozzle vane (7) and the tongue-distal nozzle vane (8) are the same. By reducing the variation amount of the load acting on the tongue-proximal nozzle vane (7), the wear of the vane shaft (53) fixed to the tongue-proximal nozzle vane (7) can be suppressed, and thus the reliability and durability of the variable displacement turbo (2) can be improved.

[0213] 12) At least one embodiment of the present disclosure relates to a supercharger (1) including:

[0214] The variable displacement turbo (2A) according to any one of the above 1) to the above 10);

[0215] The centrifugal compressor (3) is configured to be driven by the variable displacement turbo (2A).

[0216] According to the structure of the above 12), by providing the notch portion (75) on the tongue-proximal nozzle vane (7) of the variable displacement turbo (2A), the wear of the vane shaft (53) fixed to the tongue-proximal nozzle vane (7) can be suppressed, and thus the reliability and durability of the variable displacement turbo (2A) and the supercharger (1) including the variable displacement turbo (2A) can be improved.

[0217] 13) At least one embodiment of the present disclosure relates to a supercharger (1) including:

[0218] The variable displacement turbo (2B) according to the above 11);

[0219] The centrifugal compressor (3) is configured to be driven by the variable displacement turbo (2B).

[0220] According to the structure of the above 13), by shortening the maximum length (MH1) in the blade height direction of the nozzle blade (7) near the tongue portion of the variable displacement turbine (2B), wear of the blade shaft (53) fixed to the nozzle blade (7) near the tongue portion can be suppressed, and thus, the reliability and durability of the variable displacement turbine (2B) and the supercharger (1) provided with the variable displacement turbine (2B) can be improved.

[0221] BRIEF DESCRIPTION OF DRAWINGS

[0222] 1 supercharger

[0223] 1A exhaust gas turbocharger

[0224] 2, 2A, 2B variable displacement turbine

[0225] 3 centrifugal compressor

[0226] 4 exhaust gas flow path forming portion

[0227] 5 variable nozzle unit

[0228] 6 nozzle blade

[0229] 7, 7A nozzle blade near the tongue portion

[0230] 8, 8B nozzle blade far from the tongue portion

[0231] 10 internal combustion engine

[0232] 11 rotating shaft

[0233] 12 bearing

[0234] 13 housing

[0235] 14 bearing housing

[0236] 15 gas line

[0237] 16 exhaust gas line

[0238] 17 internal space

[0239] 21 turbine rotor

[0240] 22 turbine housing

[0241] 23 exhaust gas inlet

[0242] 24 exhaust gas outlet

[0243] 25 scroll flow path

[0244] 26 scroll flow path forming portion

[0245] 27 exhaust gas discharge path

[0246] 28 exhaust gas discharge passage forming portion

[0247] 29 tongue portion

[0248] 31 impeller

[0249] 32 compressor housing

[0250] 33 gas introduction port

[0251] 34 gas discharge port

[0252] 35 gas introduction passage

[0253] 36 gas introduction passage forming portion

[0254] 37 scroll flow passage

[0255] 38 scroll flow passage forming portion

[0256] 40 exhaust gas flow passage

[0257] 40A tongue portion vicinity region

[0258] 40B tongue portion distal region

[0259] 41 nozzle seat

[0260] 42 nozzle plate

[0261] 43, 45 annular plate portion

[0262] 44 hub side flow passage surface

[0263] 46 protrusion

[0264] 47 shroud side flow passage surface

[0265] 48 shroud surface

[0266] 49 nozzle support

[0267] 51 rotation mechanism portion

[0268] 52 drive ring

[0269] 53 blade shaft

[0270] 54 lever plate

[0271] 55 actuator

[0272] 56 drive shaft

[0273] 57 controller

[0274] 60, 70, 80 blade surface

[0275] 60A, 70A, 80A pressure surface

[0276] 60B, 70B, 80B negative pressure surface

[0277] 61, 71, 81 leading edge end

[0278] 62, 72, 82 trailing edge end

[0279] 63, 73, 83 hub side end

[0280] 64, 74, 84 shroud side end

[0281] 75, 85 cutout portion

[0282] 76, 86 leading edge side cutout portion

[0283] 77, 87 trailing edge side cutout portion

[0284] A1, A2, A11, A21 area

[0285] F1, F2 area

[0286] G1, G2 gap

[0287] LA, LC axis

[0288] LR1, LR2 straight line

[0289] LV imaginary line

[0290] P1 last edge point

[0291] P2 first edge point

[0292] PH blade height position

[0293] PL lower limit value of pressure

[0294] PS blade length position

[0295] PU upper limit value of pressure

[0296] RC rotation center

[0297] T1 cycle

[0298] VL, VL1 to VL8 load

[0299] WH blade height direction

[0300] WS blade length direction

[0301] X axial direction (of the rotation axis)

[0302] XC compressor side

[0303] XT turbine side

[0304] Y radial direction (of the rotation axis)

Claims

1. A variable capacity turbine, characterized in that, have: Turbine rotor; A vortex flow path forming section forms a vortex flow path on the outer peripheral side of the turbine rotor; An exhaust gas flow path forming section is formed to guide exhaust gas from the vortex flow path to the turbine rotor; A variable nozzle unit is used to adjust the flow of the exhaust gas in the exhaust gas flow path. The variable nozzle unit includes: Multiple nozzle blades are arranged at intervals along the circumference of the turbine rotor in the exhaust gas flow path; The rotating mechanism is configured to cause the plurality of nozzle blades to rotate about their respective rotation centers. When the exhaust gas flow path is divided into a near-tongue region located near the tongue of the vortex flow path and a region outside the near-tongue region, i.e., a distal tongue region, the plurality of nozzle blades include at least one near-tongue nozzle blade located in the near-tongue region and at least one distal tongue nozzle blade located in the distal tongue region. The at least one tongue-near nozzle blade has a larger cut at at least one of its leading or trailing edge ends than the leading or trailing edge ends of the tongue-faring nozzle blade.

2. The variable capacity turbine according to claim 1, wherein, The at least one nozzle blade near the tongue has a cutout portion, i.e., a trailing edge side cutout portion, formed at the trailing edge end of the nozzle blade near the tongue. When the leaf length position of the nozzle blade near the tongue in the direction of leaf length from the leading edge to the trailing edge is set to 0%, and the leaf length position of the trailing edge in the direction of leaf length is set to 100%, at least a portion of the trailing edge cut is formed in a region where the leaf length position is within the range of 75% to 100%.

3. The variable capacity turbine according to claim 2, wherein, When the blade height position of the nozzle blade near the tongue in the direction from the hub side to the shield side is set to 0%, and the blade height position of the shield side in the direction of blade height is set to 100%, at least a portion of the trailing edge side cut is formed in a region where the blade height position is within the range of 15% to 85%.

4. The variable capacity turbine according to claim 2, wherein, The at least one nozzle blade near the tongue has a cut-out portion, i.e., a leading edge side cut-out portion, formed at the leading edge end of the nozzle blade near the tongue. At least a portion of the leading edge lateral cut is formed in the region where the leaf length position is within the range of 0% to 25%.

5. The variable capacity turbine according to claim 4, wherein, When the blade height position of the nozzle blade near the tongue in the direction from the hub side to the shield side is set to 0%, and the blade height position of the shield side in the direction of blade height is set to 100%, at least a portion of the leading edge side cut is formed in a region where the blade height position is within the range of 15% to 85%.

6. The variable capacity turbine according to claim 4, wherein, The nozzle blades near at least one tongue are configured such that the leading edge side cutout and the trailing edge side cutout are of the same size.

7. The variable capacity turbine according to claim 4, wherein, The nozzle blades near at least one tongue are configured such that the size of the trailing edge side cut is larger than the leading edge side cut.

8. The variable capacity turbine according to claim 1, wherein, Compared to the nozzle blades distal to the tongue, the nozzle blades near the tongue have a shorter maximum length in the blade height direction from the hub side to the shield side.

9. The variable capacity turbine according to claim 8, wherein, When the maximum length of the nozzle blade in the height direction from the hub side to the shield side is set to 100%, the at least one nozzle blade near the tongue is configured such that the maximum length of the nozzle blade in the height direction near the tongue is 90% or less.

10. The variable capacity turbine according to any one of claims 1 to 9, wherein, Regarding the angular position around the vortex center in the vortex flow path, if the angular position α is defined as 0° with the tongue angle gradually increasing from the tongue towards the downstream side of the vortex flow path, The region near the tongue satisfies the condition -90°≤α≤90°.

11. A variable capacity turbine, characterized in that, have: Turbine rotor; A vortex flow path forming section forms a vortex flow path on the outer peripheral side of the turbine rotor; An exhaust gas flow path forming section is formed to guide exhaust gas from the vortex flow path to the turbine rotor; A variable nozzle unit is used to adjust the flow of the exhaust gas in the exhaust gas flow path. The variable nozzle unit includes: Multiple nozzle blades are arranged at intervals along the circumference of the turbine rotor in the exhaust gas flow path; The rotating mechanism is configured to cause the plurality of nozzle blades to rotate about their respective rotation centers. When the exhaust gas flow path is divided into a region near the tongue of the vortex flow path and a region outside the tongue, i.e., a region distal to the tongue, the plurality of nozzle blades include at least one nozzle blade near the tongue in the region near the tongue and at least one nozzle blade distal to the tongue in the region distal to the tongue. Compared to the nozzle blades distal to the tongue, the nozzle blades near the tongue have a shorter maximum length in the blade height direction from the hub side to the shield side.

12. A turbocharger comprising: The variable capacity turbine according to any one of claims 1 to 10; A centrifugal compressor configured to be driven by the variable capacity turbine.

13. A booster comprising: The variable capacity turbine as described in claim 11; A centrifugal compressor configured to be driven by the variable capacity turbine.

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