Turbine shell, turbine and turbocharger

Abstract

A turbine housing that accommodates at least a part of a turbine wheel, the turbine housing being provided with: a first scroll flow path for supplying a working gas to the turbine wheel; and a first tongue part formed at the position of the outlet of the first scroll flow path, the first tongue part including an inner edge facing the leading edge of the blade of the turbine wheel across a gap in the radial direction of the turbine wheel in a cross-section along the axial direction of the turbine wheel, the inner edge including at least one inclined part inclined with respect to the axial direction, and the inclined part being formed at the position of the outlet of the first scroll flow path. The inner edge is configured so as to satisfy B > = 0.2 A, where A is the size of the range in which the leading edge is provided in the axial direction, and B is the sum of the sizes of the ranges in which each of the at least one inclined portion is provided in the axial direction.

Description

Technical Field

[0001] The invention relates to a turbine housing, a turbine and a turbocharger. Background Art

[0002] Patent Document 1 discloses a twin-scroll turbocharger in which two scroll flow paths for supplying exhaust gas are formed in a turbine impeller. Patent Document 1 also discloses a turbocharger having three scroll flow paths.

[0003] Previous technical literature

[0004] Patent Literature

[0005] Patent Document 1: U.S. Patent Application Publication No. 2015 / 0345433 Summary of the invention

[0006] Technical issues to be solved by the invention

[0007] Therefore, in the turbine of the turbocharger, noise may be generated due to interference between the vortex generated at the tongue portion formed at the outlet of the vortex flow path and the blades of the turbine impeller. This phenomenon occurs even when there is only one vortex flow path, and especially when there are more than two vortex flow paths, the rotation of the turbine changes due to the different flow efficiencies at the outlets of the vortex flow paths, and the noise tends to increase.

[0008] In view of the above circumstances, an object of at least one embodiment of the present invention is to provide a turbine housing capable of realizing a turbine having excellent quietness, and a turbine and a turbocharger including the same.

[0009] Means for solving technical problems

[0010] In order to achieve the above object, a turbine housing according to at least one embodiment of the present invention is a turbine housing that accommodates at least a portion of a turbine impeller, and includes:

[0011] a first swirl flow path for supplying working gas to the turbine impeller; and

[0012] The first tongue portion is formed at the exit of the first scroll flow path.

[0013] The first tongue portion includes an inner end edge, the inner end edge facing the leading edge of a blade of the turbine impeller with a gap in the radial direction of the turbine impeller interposed therebetween in a cross section along the axial direction of the turbine impeller,

[0014] The inner end edge includes at least one inclined portion inclined relative to the axial direction,

[0015] If the size of the range in the axial direction where the front edge is provided is A, and the total size of the range in the axial direction where the at least one inclined portion is provided is B, the inner edge is configured to satisfy B≥0.2A.

[0016] In order to achieve the above object, a turbine according to at least one embodiment of the present invention includes a turbine impeller and the above-mentioned turbine casing.

[0017] In order to achieve the above-mentioned object, a turbocharger according to at least one embodiment of the present invention includes the above-mentioned turbine.

[0018] Effects of the Invention

[0019] According to at least one embodiment of the present invention, there are provided a turbine housing capable of realizing a turbine having excellent quietness, and a turbine and a turbocharger including the same. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic cross-sectional view schematically showing an example of a cross section perpendicular to the axial direction in the turbine 4 of the turbocharger 2 according to the embodiment.

[0021] Figure 2 Yes means Figure 1 A schematic cross-sectional view showing an example of the HH cross section and an example of the II cross section.

[0022] Figure 3 Yes means Figure 1 A schematic cross-sectional view showing another example of the HH cross section and another example of the II cross section.

[0023] Figure 4 Yes means Figure 1 A schematic cross-sectional view of another example of the HH cross section and another example of the II cross section.

[0024] Figure 5 Yes means Figure 1 A schematic cross-sectional view of another example of the HH cross section and another example of the II cross section.

[0025] Figure 6 Yes means Figure 1 A schematic cross-sectional view of another example of the HH cross section and another example of the II cross section.

[0026] Figure 7 Yes means through Figure 1 The illustrated schematic cross-sectional view is an example of a cross section of the tongue portion 20A, the rotation axis O, and the tongue portion 20B in the turbine 4 along the axial direction.

[0027] Figure 8 Yes means through Figure 1The illustrated schematic cross-sectional view is an example of a cross section of the tongue portion 20A, the rotation axis O, and the tongue portion 20B in the turbine 4 along the axial direction.

[0028] Fig. 9 Yes means Figure 1 A schematic cross-sectional view of another example of the HH cross section and another example of the II cross section. DETAILED DESCRIPTION

[0029] Hereinafter, several embodiments of the present invention will be described with reference to the accompanying drawings.

[0030] The dimensions, materials, shapes, relative arrangements, and the like of the components described or illustrated in the embodiments are not intended to limit the scope of the invention but are merely illustrative examples.

[0031] For example, expressions such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric" or "coaxial" that indicate relative or absolute configuration not only indicate such configuration in a strict sense, but also indicate a state of relative displacement with a tolerance or an angle or distance that can achieve the same degree of functionality.

[0032] For example, expressions such as “same”, “equal” and “homogeneous” that indicate that things are in the same state not only indicate the same state in a strict sense, but also indicate a state in which there is a tolerance or a difference in the degree to which the same function can be obtained.

[0033] For example, expressions indicating shapes such as a quadrilateral or a cylinder not only indicate shapes such as a quadrilateral or a cylinder in a strict geometric sense, but also indicate shapes including concave-convex portions or chamfered portions as long as the same effect can be obtained.

[0034] On the other hand, the expression “having”, “set”, “equipped with”, “including” or “having” a constituent element is not an exclusive expression that excludes the existence of other constituent elements.

[0035] Figure 1 It is a schematic cross-sectional view schematically showing an example of a cross section perpendicular to the axial direction in the turbine 4 of the turbocharger 2 according to the embodiment. Figure 2 Yes means Figure 1 Schematic cross-sectional views of an example of the HH section and an example of the II section. In addition, the HH section is a section along the axial direction of the turbine 4 (the meridian plane of the turbine 4), more specifically, a section including the rotation axis O of the turbine impeller 6 and passing through the tongue portion 20A described later. And the II section is a section along the axial direction of the turbine 4 (the meridian plane of the turbine 4), more specifically, a section including the rotation axis O of the turbine impeller 6 and passing through the tongue portion 20B described later.

[0036] In addition, in this specification, unless otherwise specified, "axial" means the axial direction of the turbocharger 2, that is, the axial direction of the turbine impeller 6 of the turbine 4, "radial" means the radial direction of the turbocharger 2, that is, the radial direction of the turbine impeller 6 of the turbine 4, and "circumferential" means the circumferential direction of the turbocharger 2, that is, the circumferential direction of the turbine impeller 6 of the turbine 4.

[0037] Figure 1 and Figure 2 The turbocharger 2 shown may be, for example, a turbocharger for an automobile, and includes a turbine 4 and a compressor (not shown). The turbine 4 is a radial turbine including a turbine impeller 6 and a turbine housing 8 that accommodates the turbine impeller 6. The turbine impeller 6 is connected to an impeller of the compressor (not shown) via a rotating shaft (not shown), and is configured so that the turbine impeller 6 and the impeller rotate integrally.

[0038] The turbine housing 8 includes a shroud 14 (see Figure 2 )、Scroll flow path 16A (reference Figure 1 ) and vortex flow path 16B (reference Figure 1 ).

[0039] For example, Figure 2 As shown, the turbine impeller 6 includes a hub 10 and a plurality of blades 12 arranged at intervals along the circumferential direction on the outer peripheral surface of the hub 10. A shroud 14 is arranged opposite to the front ends 12t of the plurality of blades 12 with a gap therebetween, and an exhaust gas passage 15 (not shown) for the exhaust gas of the engine to pass through is formed between the shroud 14 and the hub 10. The exhaust gas of the engine acts as a working gas for rotating the turbine impeller 6.

[0040] For example, Figure 1 As shown, the vortex flow path 16A and the vortex flow path 16B are respectively configured to guide the exhaust gas of the engine to the turbine impeller 6. The vortex flow path 16A and the vortex flow path 16B are different from each other in the circumferential direction on the outer peripheral side of the turbine impeller 6 ( Figure 1 In the example shown, the exhaust gas impellers 12 are connected to the exhaust gas passage 15 within a range (180 degrees apart from each other in the circumferential direction) and are formed in a spiral shape around the rotation axis O of the turbine wheel 6.

[0041] For example, Figure 1As shown, the turbine housing 8 includes a tongue-shaped (protruding) tongue portion 20A, which is formed by a portion where a radially inner flow path wall 16A1 in the vortex flow path 16A and a radially outer flow path wall 16B2 in the vortex flow path 16B are connected at the position of the outlet E1 of the vortex flow path 16A. In addition, the turbine housing 8 includes a tongue-shaped (protruding) tongue portion 20B, which is formed by a portion where a radially inner flow path wall 16B1 in the vortex flow path 16B and a radially outer flow path wall 16A2 in the vortex flow path 16A are connected at the position of the outlet E2 of the vortex flow path 16B.

[0042] Below, use Figure 2 to Figure 6 , examples of the shapes of the tongue portion 20A and the tongue portion 20B are described. Figure 2 to Figure 6 Several embodiments described herein may be applicable to Figure 1 Any of the structures of the HH cross section and the II cross section shown can also be applied to Figure 1 The structure of the HH cross section and the structure of the II cross section shown in FIG. Figure 2 to Figure 6 In the case where the description of the several embodiments shown is interpreted as the description of the HH cross section, the "vortex flow path 16" in the following description means the "vortex flow path 16A", and the "tongue portion 20" means the "tongue portion 20A". Figure 2 to Figure 6 When the description of the several embodiments shown is interpreted as the description of the II section, the "vortex flow path 16" in the following description means the "vortex flow path 16B", and the "tongue portion 20" means the "tongue portion 20B".

[0043] exist Figure 2 In the cross section shown, the tongue portion 20 is formed from the wall surface 21h on the hub 10 side (compressor side) in the vortex flow path 16 to the wall surface 21s on the blade cover 14 side in the vortex flow path 16, including the radially outer end edge of the tongue portion 20, i.e., the outer end edge 22, and the radially inner end edge of the tongue portion 20, i.e., the inner end edge 24. In the example shown in the figure, the outer end edge 22 is formed parallel to the axial direction. Furthermore, the inner end edge 24 and the leading edge 12LE of the blade 12 of the turbine impeller 6 are opposite to each other with a radial gap d therebetween. Figure 2 In the cross-sectional view shown, the leading edge 12LE of the blade 12 of the turbine impeller 6 extends in parallel with the axial direction along the axial direction.

[0044] exist Figure 2 In the cross section shown, the inner end edge 24 includes at least one inclined portion 26 inclined relative to the axial direction. Figure 2In the exemplary embodiment shown, the inner edge 24 is formed by only one inclined portion 26 inclined relative to the axial direction in the cross section along the axial direction, and the inclined portion 26 extends linearly toward the outer side in the radial direction as it moves from the hub 10 side in the axial direction toward the shroud 14 side. Figure 2 In the illustrated cross section, the inclined portion 26 is formed over the entire inner edge 24 from a wall surface 21 h of the scroll flow path 16 on the hub 10 side to a wall surface 21 s of the scroll flow path 16 on the shroud 14 side.

[0045] exist Figure 2 In the cross section shown, if the size of the range in which the leading edge 12LE is provided in the axial direction is A and the size of the range in which the inclined portion 26 is provided in the axial direction is B, the inner edge 24 is formed to satisfy B≥0.2A. In the example shown in the figure, the inner edge 24 is formed to satisfy B≥0.5 and B≥0.8.

[0046] And, in Figure 2 In the cross section shown, if the minimum value of the gap d between the inner end edge 24 and the leading edge 12LE is set to dmin, the maximum value of the gap d between the inner end edge 24 and the leading edge 12LE is set to dmax, and the diameter of the turbine impeller 6 is set to D, the inner end edge 24 is formed to satisfy dmin / D≥0.02 and dmax / D≤0.09.

[0047] according to Figure 2 In the structure shown, since the inner edge 24 of the tongue portion 20 includes the inclined portion 26 inclined with respect to the axial direction, the gap d between the inner edge 24 of the tongue portion 20 and the leading edge 12LE of the blade 12 of the turbine impeller 6 changes according to the axial position within the range where the inclined portion 26 in the axial direction is formed. Therefore, the intensity of the vortex generated by the tongue portion 20 can be weakened, and the generation of noise caused by the interference between the vortex generated by the tongue portion 20 and the leading edge 12LE of the blade 12 can be suppressed.

[0048] Furthermore, by satisfying B ≥ 0.2A, in more than half of the range A where the leading edge 12LE of the blade 12 is provided in the axial direction, the gap d between the inner edge 24 of the tongue portion 20 and the leading edge 12LE of the blade 12 changes according to the axial position. Therefore, the intensity of the vortex generated by the tongue portion 20 can be effectively weakened, and the generation of noise caused by the interference between the vortex generated by the tongue portion 20 and the leading edge 12LE of the blade 12 can be effectively suppressed. Thus, a turbine housing 8 capable of realizing a turbine 4 with excellent quietness can be provided. Furthermore, since the inclined portion 26 is formed on the entire inner edge 24, the complication of the shape of the tongue portion 20 can be suppressed, and the generation of noise caused by the interference between the vortex generated from the tongue portion 20 and the leading edge 12LE of the blade 12 can be suppressed.

[0049] Furthermore, as the gap between the inner end edge 24 of the tongue portion 20 and the leading edge 12LE of the blade 12 becomes smaller, the performance of the turbine 4 improves, but the noise tends to increase. However, as described above, by satisfying dmin / D≥0.02 and dmax / D≤0.09, good performance of the turbine 4 can be achieved, and the increase in noise caused by the interference between the vortex generated by the tongue portion 20 and the leading edge 12LE of the blade 12 can be suppressed.

[0050] Figure 3 Yes means Figure 1 A schematic cross-sectional view showing another example of the HH cross section and another example of the II cross section.

[0051] exist Figure 3 In the exemplary embodiment shown, the inclined portion 26 of the inner edge 24 of the tongue portion 20 is inclined relative to the axial direction, and extends linearly in a manner directed radially inward from the hub 10 side in the axial direction toward the shroud 14 side in a cross section along the axial direction. Figure 3 In the cross section shown, the inclined portion 26 is formed over the entire inner edge 24 from the wall surface 21h of the scroll flow path 16 on the hub 10 side to the wall surface 21s of the scroll flow path 16 on the shroud 14 side. Figure 3 In the cross section shown, the leading edge 12LE of the blade 12 of the turbine wheel 6 extends in parallel with the axial direction.

[0052] exist Figure 3 In the cross section shown, if the size of the range in which the leading edge 12LE is provided in the axial direction is set as A, and the size of the range in which the inclined portion 26 is provided in the axial direction is set as B, the inner edge 24 is formed to satisfy B≥0.2A. In the example shown in the figure, the inner edge 24 is formed to satisfy B≥0.5 and B≥0.8. Figure 3 In the cross section shown, although not shown in the figure, if the minimum value of the gap between the inner end edge 24 and the leading edge 12LE is set to dmin, the maximum value of the gap between the inner end edge 24 and the leading edge 12LE is set to dmax, and the diameter of the turbine impeller 6 is set to D, the inner end edge 24 is formed to satisfy dmin / D≥0.02 and dmax / D≤0.09.

[0053] exist Figure 3In the structure shown, within the range where the inclined portion 26 in the axial direction is formed, the gap d between the inner edge 24 of the tongue portion 20 and the leading edge 12LE of the blade 12 of the turbine impeller 6 changes according to the axial position. Therefore, the intensity of the vortex generated by the tongue portion 20 can be weakened, and the generation of noise caused by the interference between the vortex generated by the tongue portion 20 and the leading edge 12LE of the blade 12 can be suppressed. In addition, by satisfying B≥0.2A, the intensity of the vortex generated by the tongue portion 20 can be effectively weakened, and the generation of noise caused by the interference between the vortex generated by the tongue portion 20 and the leading edge 12LE of the blade 12 can be effectively suppressed. Thus, a turbine housing capable of realizing a turbine with excellent quietness can be provided. In addition, by satisfying dmin / D≥0.02 and dmax / D≤0.09, good performance of the turbine 4 can be achieved, and the increase of noise caused by the interference between the vortex generated by the tongue portion 20 and the leading edge 12LE of the blade 12 can be suppressed. Furthermore, since the inclined portion 26 is formed on the entire inner end edge 24 , the shape of the tongue portion 20 can be prevented from being complicated, and the generation of noise caused by the interference between the vortex generated from the tongue portion 20 and the leading edge 12LE of the blade 12 can be prevented.

[0054] Figure 4 Yes means Figure 1 A schematic cross-sectional view of another example of the HH cross section and another example of the II cross section.

[0055] exist Figure 4 In the exemplary embodiment shown, the inner edge 24 of the tongue portion 20 includes a parallel portion 25 parallel to the axial direction and an inclined portion 26 inclined relative to the axial direction in a cross section along the axial direction. Figure 4 In the cross section shown, one end of the parallel portion 25 is connected to the wall surface 21h on the hub 10 side of the vortex flow path 16, and the other end of the parallel portion 25 is connected to one end of the inclined portion 26. The other end of the inclined portion 26 is connected to the wall surface 21s on the shroud 14 side of the vortex flow path 16. Figure 4 In the cross section shown, the inclined portion 26 extends linearly toward the outer side in the radial direction as it moves from the hub 10 side in the axial direction toward the shroud 14 side. Figure 4 In the cross section shown, the leading edge 12LE of the blade 12 of the turbine wheel 6 extends in parallel with the axial direction.

[0056] exist Figure 4 In the cross section shown, if the size of the range in which the leading edge 12LE is provided in the axial direction is defined as A, and the size of the range in which the inclined portion 26 is provided in the axial direction is defined as B, the inner edge 24 is formed to satisfy B ≥ 0.2A. Figure 4In the cross section shown, although not shown in the figure, if the minimum value of the gap between the inner end edge 24 and the leading edge 12LE is set to dmin, the maximum value of the gap between the inner end edge 24 and the leading edge 12LE is set to dmax, and the diameter of the turbine impeller 6 is set to D, the inner end edge 24 is formed to satisfy dmin / D≥0.02 and dmax / D≤0.09.

[0057] according to Figure 4 In the structure shown, within the range where the axially inclined portion 26 is formed, the gap d between the inner edge 24 of the tongue portion 20 and the leading edge 12LE of the blade 12 of the turbine impeller 6 changes according to the axial position. Therefore, the intensity of the vortex generated by the tongue portion 20 can be weakened, and the generation of noise caused by the interference between the vortex generated by the tongue portion 20 and the leading edge 12LE of the blade 12 can be suppressed. In addition, by satisfying B≥0.2A, the intensity of the vortex generated by the tongue portion 20 can be effectively weakened, and the generation of noise caused by the interference between the vortex generated by the tongue portion 20 and the leading edge 12LE of the blade 12 can be effectively suppressed. Thus, a turbine housing capable of realizing a turbine with excellent quietness can be provided. In addition, by satisfying dmin / D≥0.02 and dmax / D≤0.09, good performance of the turbine 4 can be achieved, and the increase of noise caused by the interference between the vortex generated by the tongue portion 20 and the leading edge 12LE of the blade 12 can be suppressed.

[0058] Figure 5 Yes means Figure 1 A schematic cross-sectional view of another example of the HH cross section and another example of the II cross section.

[0059] exist Figure 5 In the exemplary embodiment shown, the inner edge 24 of the tongue portion 20 has a convex shape 28 that protrudes radially inward in a cross section along the axial direction. Figure 5 In the cross section shown, the inner edge 24 of the tongue portion 20 includes a parallel portion 25 parallel to the axial direction, an inclined portion 26a inclined relative to the axial direction, and an inclined portion 26b inclined relative to the axial direction. Figure 5 In the cross section shown, one end of the inclined portion 26a is connected to the wall surface 21h on the hub 10 side of the vortex flow path 16, and the other end of the inclined portion 26a is connected to one end of the parallel portion 25. In addition, the other end of the parallel portion 25 is connected to one end of the inclined portion 26b, and the other end of the inclined portion 26b is connected to the wall surface 21s on the shroud 14 side of the vortex flow path 16. Figure 5 In the cross section shown, the inclined portion 26a extends linearly in a manner that moves radially inward from the hub 10 side in the axial direction toward the shroud 14 side, and the inclined portion 26b extends linearly in a manner that moves radially outward from the hub 10 side in the axial direction toward the shroud 14 side. Figure 5In the cross section shown, the leading edge 12LE of the blade 12 of the turbine wheel 6 extends in parallel with the axial direction.

[0060] exist Figure 5 In the cross section shown, if the size of the range in which the leading edge 12LE is provided in the axial direction is set as A, the size of the range in which the inclined portion 26a is provided in the axial direction is set as b1, the size of the range in which the inclined portion 26b is provided in the axial direction is set as b2, and the sum of the size b1 of the range in which the inclined portion 26a is provided in the axial direction and the size b2 of the range in which the inclined portion 26b is provided in the axial direction is set as B (= b1 + b2), the inner edge 24 is formed to satisfy B ≥ 0.2A. And, in Figure 5 In the cross section shown, although not shown in the figure, if the minimum value of the gap between the inner end edge 24 and the leading edge 12LE is set to dmin, the maximum value of the gap between the inner end edge 24 and the leading edge 12LE is set to dmax, and the diameter of the turbine impeller 6 is set to D, the inner end edge 24 is formed to satisfy dmin / D≥0.02 and dmax / D≤0.09.

[0061] exist Figure 5 In the structure shown, within the range where the inclined portion 26a is formed in the axial direction, the gap d between the inner edge 24 of the tongue portion 20 and the leading edge 12LE of the blade 12 can be made smaller as it moves from the hub 10 side to the shroud 14 side in the axial direction. Furthermore, within the range where the inclined portion 26b is formed in the axial direction, the gap d between the inner edge 24 of the tongue portion 20 and the leading edge 12LE of the blade 12 can be made larger as it moves from the hub 10 side to the shroud 14 side in the axial direction. In this way, by narrowing or widening the gap d between the inner edge 24 of the tongue portion 20 and the leading edge 12LE of the blade 12 from the hub 10 side to the shroud 14 side in the axial direction, the strength of the vortex generated by the tongue portion 20 can be effectively weakened, and the generation of noise caused by the interference between the vortex generated by the tongue portion 20 and the leading edge 12LE of the blade 12 can be effectively suppressed. Furthermore, by satisfying B≥0.2A, the intensity of the vortex generated by the tongue portion 20 can be effectively weakened, and the generation of noise caused by the interference between the vortex generated by the tongue portion 20 and the leading edge 12LE of the blade 12 can be effectively suppressed. Furthermore, by satisfying dmin / D≥0.02 and dmax / D≤0.09, good performance of the turbine 4 can be achieved, and the increase of noise caused by the interference between the vortex generated by the tongue portion 20 and the leading edge 12LE of the blade 12 can be suppressed.

[0062] Figure 6 Yes means Figure 1 A schematic cross-sectional view of another example of the HH cross section and another example of the II cross section.

[0063] exist Figure 6In the illustrated exemplary embodiment, the inner edge 24 of the tongue portion 20 includes two convex shapes 28 protruding radially inward in a cross section along the axial direction. The two convex shapes 28 are formed side by side along the axial direction, and a concave shape 29 is formed between the two convex shapes 28 in the axial direction.

[0064] exist Figure 6 In the exemplary embodiment shown, the inner edge 24 of the tongue portion 20 includes parallel portions 25a, 25b, 25c parallel to the axial direction and inclined portions 26a, 26b, 26c, 26d inclined relative to the axial direction in a cross section along the axial direction. Figure 6 In the cross section shown, one end of the inclined portion 26a is connected to the wall surface 21h on the hub 10 side in the vortex flow path 16, and the other end of the inclined portion 26a is connected to one end of the parallel portion 25a. In addition, the other end of the parallel portion 25a is connected to one end of the inclined portion 26b, and the other end of the inclined portion 26b is connected to one end of the parallel portion 25b. The other end of the parallel portion 25b is connected to one end of the inclined portion 26c, and the other end of the inclined portion 26c is connected to one end of the parallel portion 25c. The other end of the parallel portion 25c is connected to one end of the inclined portion 26d, and the other end of the inclined portion 26d is connected to the wall surface 21s on the shroud 14 side in the vortex flow path 16.

[0065] exist Figure 6 In the cross section shown, the inclined portion 26a extends linearly in a manner that goes from the hub 10 side in the axial direction toward the shroud 14 side and toward the radial inner side, and the inclined portion 26b extends linearly in a manner that goes from the hub 10 side in the axial direction toward the shroud 14 side and toward the radial outer side. Furthermore, the inclined portion 26c extends linearly in a manner that goes from the hub 10 side in the axial direction toward the radial inner side toward the shroud 14 side, and the inclined portion 26d extends linearly in a manner that goes from the hub 10 side in the axial direction toward the radial outer side toward the shroud 14 side. Figure 6 In the cross section shown, the leading edge 12LE of the blade 12 of the turbine wheel 6 extends in parallel with the axial direction.

[0066] exist Figure 6In the cross section shown, if the size of the range in which the leading edge 12LE is provided in the axial direction is set as A, the size of the range in which the inclined portion 26a is provided in the axial direction is set as b1, the size of the range in which the inclined portion 26b is provided in the axial direction is set as b2, the size of the range in which the inclined portion 26c is provided in the axial direction is set as b3, the size of the range in which the inclined portion 26d is provided in the axial direction is set as b4, and the sum of the size b1 of the range in which the inclined portion 26a is provided in the axial direction, the size b2 of the range in which the inclined portion 26b is provided in the axial direction, the size b3 of the range in which the inclined portion 26c is provided in the axial direction, and the size b4 of the range in which the inclined portion 26d is provided in the axial direction is set as B (= b1 + b2 + b3 + b4), then the inner edge 24 is formed to satisfy B ≥ 0.2A. And, in Figure 6 In the cross section shown, if the minimum value of the gap between the inner end edge 24 and the leading edge 12LE is set to dmin, the maximum value of the gap between the inner end edge 24 and the leading edge 12LE is set to dmax, and the diameter of the turbine impeller 6 is set to D, the inner end edge 24 is formed to satisfy dmin / D≥0.02 and dmax / D≤0.09.

[0067] exist Figure 6 In the structure shown, it is possible to Figure 5 The structure shown further enhances the effect of expanding or reducing the gap d between the inner edge 24 of the tongue portion 20 and the leading edge 12LE of the blade 12 as it moves from the hub 10 side toward the shroud 14 side in the axial direction (the effect of reducing the strength of the vortex generated from the tongue portion 20), and can effectively suppress the generation of noise caused by the interference between the vortex generated by the tongue portion 20 and the leading edge 12LE of the blade 12. Furthermore, by satisfying B≥0.2A, the strength of the vortex generated by the tongue portion 20 can be effectively reduced, and the generation of noise caused by the interference between the vortex generated by the tongue portion 20 and the leading edge 12LE of the blade 12 can be effectively suppressed. Furthermore, by satisfying dmin / D≥0.02 and dmax / D≤0.09, good performance of the turbine 4 can be achieved, and the increase in noise caused by the interference between the vortex generated by the tongue portion 20 and the leading edge 12LE of the blade 12 can be suppressed.

[0068] Figure 7 Yes means through Figure 1 The illustrated schematic cross-sectional view is an example of a cross section of the tongue portion 20A, the rotation axis O, and the tongue portion 20B in the turbine 4 along the axial direction.

[0069] exist Figure 7 In the exemplary embodiment shown, the tongue portion 20A has Figure 2 The tongue portion 20B has the same structure as shown in FIG. Figure 3 The same structure as shown in Figure 7In the turbine 4 shown, in the cross section along the axial direction, the inner edge 24 of the tongue portion 20A includes an inclined portion 26d extending radially outward from the hub 10 side in the axial direction toward the shroud 14 side, and the inner edge 24 of the tongue portion 20B includes an inclined portion 26e extending radially inward from the hub 10 side in the axial direction toward the shroud 14 side. Figure 7 In the cross section shown, the leading edge 12LE of the blade 12 of the turbine impeller 6 extends in parallel with the axial direction along the axial direction. Furthermore, the range where the inclined portion 26e is provided in the axial direction overlaps with at least a part of the range where the inclined portion 26d is provided in the axial direction (in the example shown in the figure, the entire range where the inclined portion 26e is provided in the axial direction).

[0070] exist Figure 7 In the turbine 4 shown, by setting the inclination direction of the inclined portion 26d and the inclination direction of the inclined portion 26e in opposite directions, the strength or direction of the eddy current generated by the tongue portion 20A and the strength or direction of the eddy current generated by the tongue portion 20B can be made uneven at the same position in the axial direction, and the noise caused by the eddy current generated by the tongue portion 20A and the noise caused by the eddy current generated by the tongue portion 20B can be suppressed from mutually reinforcing. Thus, a turbine housing 8 capable of realizing a turbine 4 with excellent quietness can be provided.

[0071] Figure 8 Yes means through Figure 1 The illustrated schematic cross-sectional view is an example of a cross section of the tongue portion 20A, the rotation axis O, and the tongue portion 20B in the turbine 4 along the axial direction.

[0072] exist Figure 8 In the exemplary embodiment shown, the tongue portion 20A and the tongue portion 20B have Figure 4 The tongue portion 20 shown has the same structure. Figure 8 In the turbine 4 shown, in a cross section along the axial direction, if a gap d between the inner end edge 24 of the tongue portion 20A and the leading edge 12LE of the blade 12 and a gap d between the inner end edge 24 of the tongue portion 20B and the leading edge 12LE of the blade 12 are compared at the same position in the axial direction, the gap d between the inner end edge 24 of the tongue portion 20A and the leading edge 12LE of the blade 12 and the gap d between the inner end edge 24 of the tongue portion 20B and the leading edge 12LE of the blade 12 are different in at least a part of the range in the axial direction (in the example shown in the figure, the entire range in the axial direction where the inner end edge 24 of the tongue portion 20A is formed).

[0073] exist Figure 8In the cross section shown, the inner edge 24 of the tongue portion 20A and the inner edge 24 of the tongue portion 20B each include a parallel portion 25 parallel to the axial direction and an inclined portion 26 inclined relative to the axial direction. Figure 8 In the cross section shown, the leading edge 12LE of the blade 12 of the turbine impeller 6 extends in parallel with the axial direction along the axial direction. Here, the gap d between the parallel portion 25 of the tongue portion 20A and the leading edge 12LE of the blade 12 is larger than the gap d between the parallel portion 25 of the tongue portion 20B and the leading edge 12LE of the blade 12. Furthermore, if the gap d between the inclined portion 26 of the tongue portion 20A and the leading edge 12LE of the blade 12 is compared with the gap d between the inclined portion 26 of the tongue portion 20B and the leading edge 12LE of the blade 12 at the same position in the axial direction, the gap d between the inclined portion 26 of the tongue portion 20A and the leading edge 12LE of the blade 12 is larger than the gap d between the inclined portion 26 of the tongue portion 20B and the leading edge 12LE of the blade 12 in the entire range where the inclined portion 26 of the tongue portion 20A is formed in the axial direction.

[0074] exist Figure 8 In the turbine 4 shown, by making the gap d between the inner edge 24 of the tongue portion 20A and the leading edge 12LE of the blade 12 and the gap d between the inner edge 24 of the tongue portion 20B and the leading edge 12LE of the blade 12 different in at least a part of the axial direction, the strength or direction of the eddy current generated by the tongue portion 20A and the strength or direction of the eddy current generated by the tongue portion 20B can be made uneven at the same position in the axial direction, and the noise caused by the eddy current generated by the tongue portion 20A and the noise caused by the eddy current generated by the tongue portion 20B can be suppressed from mutually reinforcing. Thus, a turbine housing 8 capable of realizing a turbine 4 with excellent quietness can be provided.

[0075] Fig. 9 Yes means Figure 1 A schematic cross-sectional view of another example of the HH cross section and another example of the II cross section.

[0076] exist Fig. 9 In the exemplary embodiment shown, the inner edge 24 of the tongue portion 20 has a concave shape 29 that is recessed toward the outside in the radial direction in a cross section along the axial direction. Fig. 9 In the cross section shown, the inner edge 24 of the tongue portion 20 includes a parallel portion 25 parallel to the axial direction, an inclined portion 26f inclined relative to the axial direction, and an inclined portion 26g inclined relative to the axial direction. Fig. 9 In the cross section shown, one end of the inclined portion 26f is connected to the wall surface 21h on the hub 10 side of the vortex flow path 16, and the other end of the inclined portion 26f is connected to one end of the parallel portion 25. In addition, the other end of the parallel portion 25 is connected to one end of the inclined portion 26g, and the other end of the inclined portion 26g is connected to the wall surface 21s on the shroud 14 side of the vortex flow path 16. Fig. 9 In the cross section shown, the inclined portion 26f extends linearly in a manner that is directed radially outward from the hub 10 side in the axial direction toward the shroud 14 side, and the inclined portion 26g extends linearly in a manner that is directed radially inward from the hub 10 side in the axial direction toward the shroud 14 side. Fig. 9 In the cross section shown, the leading edge 12LE of the blade 12 of the turbine wheel 6 extends in parallel with the axial direction.

[0077] exist Fig. 9 In the cross section shown, if the size of the range in which the leading edge 12LE is provided in the axial direction is set as A, the size of the range in which the inclined portion 26f is provided in the axial direction is set as b1, the size of the range in which the inclined portion 26g is provided in the axial direction is set as b2, and the sum of the size b1 of the range in which the inclined portion 26f is provided in the axial direction and the size b2 of the range in which the inclined portion 26g is provided in the axial direction is set as B (= b1 + b2), the inner edge 24 is formed to satisfy B ≥ 0.2A. And, in Fig. 9 In the cross section shown, although not shown in the figure, if the minimum value of the gap between the inner end edge 24 and the leading edge 12LE is set to dmin, the maximum value of the gap between the inner end edge 24 and the leading edge 12LE is set to dmax, and the diameter of the turbine impeller 6 is set to D, the inner end edge 24 is formed to satisfy dmin / D≥0.02 and dmax / D≤0.09.

[0078] exist Fig. 9 In the structure shown, within the range where the inclined portion 26f is formed in the axial direction, the gap d between the inner edge 24 of the tongue portion 20 and the leading edge 12LE of the blade 12 can be made larger as it moves from the hub 10 side in the axial direction toward the shroud 14 side. Also, within the range where the inclined portion 26g is formed in the axial direction, the gap d between the inner edge 24 of the tongue portion 20 and the leading edge 12LE of the blade 12 can be made smaller as it moves from the hub 10 side in the axial direction toward the shroud 14 side. In this way, by increasing or decreasing the gap d between the inner edge 24 of the tongue portion 20 and the leading edge 12LE of the blade 12 as it moves from the hub 10 side in the axial direction toward the shroud 14 side, the strength of the eddy current generated by the tongue portion 20 can be effectively weakened, and the generation of noise caused by the interference between the eddy current generated by the tongue portion 20 and the leading edge 12LE of the blade 12 can be effectively suppressed. Furthermore, by satisfying B≥0.2A, the intensity of the vortex generated by the tongue portion 20 can be effectively weakened, and the generation of noise caused by the interference between the vortex generated by the tongue portion 20 and the leading edge 12LE of the blade 12 can be effectively suppressed. Furthermore, by satisfying dmin / D≥0.02 and dmax / D≤0.09, good performance of the turbine 4 can be achieved, and the increase of noise caused by the interference between the vortex generated by the tongue portion 20 and the leading edge 12LE of the blade 12 can be suppressed.

[0079] The present invention is not limited to the above-described embodiments, and includes modified embodiments of the above-described embodiments or embodiments in which these embodiments are appropriately combined.

[0080] For example, in the above-described embodiments, the turbine 4 is illustrated as having two scroll flow passages 16A and 16B, but the number of scroll flow passages 16 provided in the turbine 4 may be one or three or more.

[0081] The contents described in the above-mentioned embodiments can be understood, for example, as follows.

[0082] (1) A turbine housing (for example, the turbine housing 8 ) according to at least one embodiment of the present invention is a turbine housing that accommodates at least a portion of a turbine impeller (for example, the turbine impeller 6 ), and includes:

[0083] a first scroll flow path (for example, the scroll flow path 16 ( 16A or 16B)) for supplying working gas to the turbine impeller; and

[0084] The first tongue portion (for example, the tongue portion 20 (20A or 20B)) is formed at the position of the outlet (for example, the outlet E1 or E2) of the first scroll flow path.

[0085] The first tongue portion includes an inner end edge (e.g., the inner end edge 24) which, in a cross section along the axial direction of the turbine impeller, faces a leading edge (e.g., the leading edge 12LE) of a blade (e.g., the blade 12) of the turbine impeller with a gap (e.g., the gap d) in the radial direction of the turbine impeller interposed therebetween.

[0086] The inner end edge includes at least one inclined portion (for example, the inclined portions 26, 26a, 26b, 26c, 26d, 26e) inclined relative to the axial direction.

[0087] If the size of the range in the axial direction where the front edge is provided is A, and the total size of the range in the axial direction where the at least one inclined portion is provided is B, the inner edge is configured to satisfy B≥0.2A.

[0088] According to the turbine housing described in (1), since the inner edge of the first tongue portion includes at least one inclined portion inclined relative to the axial direction, the gap between the inner edge of the first tongue portion and the leading edge of the blade of the turbine impeller changes according to the axial position within the range where the at least one inclined portion is formed. Therefore, the intensity of the vortex generated by the first tongue portion can be weakened, and the generation of noise caused by the interference between the vortex generated by the first tongue portion and the leading edge of the blade of the turbine impeller can be suppressed.

[0089] Furthermore, by satisfying B ≥ 0.2A, in more than half of the range where the leading edge of the blade of the turbine impeller is provided in the axial direction, the gap between the inner edge of the first tongue portion and the leading edge of the blade of the turbine impeller changes according to the axial position. Therefore, the intensity of the vortex generated by the first tongue portion can be effectively weakened, and the generation of noise caused by the interference between the vortex generated by the tongue portion and the leading edge of the blade of the turbine impeller can be effectively suppressed. Thus, a turbine housing capable of realizing a turbine with excellent quietness can be provided.

[0090] (2) In some embodiments, in the turbine housing described in (1) above,

[0091] The inner edge includes a first inclined portion (eg, Figure 2 and Figure 4 The inclined portion 26 shown, Figure 5 The inclined portion 26b shown, Figure 6 The inclined portions 26b, 26d, Figure 7 The inclined portion 26d and Figure 8 The first inclined portion is inclined toward the outer side in the radial direction as it moves from the hub side of the turbine impeller toward the shroud side in the axial direction.

[0092] According to the turbine housing described in (2) above, within the range in which the first inclined portion is formed in the axial direction, the gap between the inner edge of the first tongue portion and the leading edge of the blade of the turbine impeller can be made larger as it moves from the hub side in the axial direction toward the shroud side. Therefore, the intensity of the vortex generated by the first tongue portion can be weakened, and the generation of noise caused by the interference between the vortex generated by the first tongue portion and the leading edge of the blade of the turbine impeller can be suppressed. Therefore, it is possible to provide a turbine housing capable of realizing a turbine with excellent quietness.

[0093] (3) In some embodiments, in the turbine housing described in (1) above,

[0094] The inner edge includes a first inclined portion (eg, Figure 3 The inclined portion 26 shown, Figure 5 The inclined portion 26a shown, Figure 6 The inclined portions 26a, 26c and Figure 7 As shown in the inclined portion 26e, the first inclined portion is inclined toward the inner side in the radial direction as it moves from the hub side of the turbine impeller in the axial direction toward the shroud side.

[0095] According to the turbine housing described in (3) above, within the range in which the first inclined portion is formed in the axial direction, the gap between the inner edge of the first tongue portion and the leading edge of the blade of the turbine impeller can be made smaller as it moves from the hub side in the axial direction toward the shroud side. Therefore, the intensity of the vortex generated by the first tongue portion can be weakened, and the generation of noise caused by the interference between the vortex generated by the first tongue portion and the leading edge of the blade of the turbine impeller can be suppressed. Therefore, a turbine housing capable of realizing a turbine with excellent quietness can be provided.

[0096] (4) In some embodiments, in the turbine housing described in (2) or (3) above, the first inclined portion is formed over the entire inner end edge.

[0097] According to the turbine housing described in (4) above, the shape of the first tongue portion is prevented from becoming complicated, and the generation of noise due to interference between the vortex generated by the first tongue portion and the leading edge of the blade of the turbine impeller can be prevented.

[0098] (5) In some embodiments, in the turbine housing described in (2) or (3) above,

[0099] The inner end edge includes a parallel portion parallel to the axial direction (for example, the parallel portions 25 , 25 a , 25 b , 25 c ).

[0100] According to the turbine housing described in (5) above, it is possible to suppress the complexity of the shape of the first tongue portion and suppress the generation of noise caused by interference between the vortex generated by the first tongue portion and the leading edge of the blade of the turbine impeller.

[0101] (6) In some embodiments, in the turbine housing described in (1) above,

[0102] The inner edge includes: a first inclined portion (for example, Figure 5 The inclined portion 26b shown, Figure 6 The inclined portions 26b, 26d shown in the figure are inclined toward the outer side in the radial direction as they move from the hub side of the turbine impeller in the axial direction toward the shroud side; and a second inclined portion (for example, Figure 5 The inclined portion 26a shown, Figure 6 The inclined portions 26a, 26c shown in the figure are inclined in the axial direction so as to be directed inward in the radial direction as they move from the hub side of the turbine impeller toward the shroud side.

[0103] According to the turbine housing described in (6) above, within the range where the first inclined portion is formed in the axial direction, the gap between the inner edge of the first tongue portion and the leading edge of the blade of the turbine impeller can be made larger as it moves from the hub side in the axial direction toward the shroud side. Furthermore, within the range where the second inclined portion is formed in the axial direction, the gap between the inner edge of the first tongue portion and the leading edge of the blade of the turbine impeller can be made smaller as it moves from the hub side in the axial direction toward the shroud side. In this way, by expanding or reducing the gap between the inner edge of the first tongue portion and the leading edge of the blade of the turbine impeller as it moves from the hub side in the axial direction toward the shroud side, the intensity of the vortex generated by the first tongue portion can be effectively weakened, and the generation of noise caused by the interference between the vortex generated by the first tongue portion and the leading edge of the blade of the turbine impeller can be effectively suppressed.

[0104] (7) In some embodiments, in the turbine casing described in any one of (1) to (6) above, if the minimum value of the gap between the inner end edge and the leading edge is set to dmin, the maximum value of the gap between the inner end edge and the leading edge is set to dmax, and the diameter of the turbine impeller is set to D, then dmin / D≥0.02 and dmax / D≤0.09 are satisfied.

[0105] As the gap between the inner edge of the first tongue portion and the leading edge of the blade of the turbine impeller decreases, the performance of the turbine improves, but the noise increases. In this regard, according to the turbine housing described in (7), by satisfying dmin / D ≥ 0.02 and dmax / D ≤ 0.09, it is possible to achieve good turbine performance and suppress the increase in noise caused by the interference between the vortex generated by the first tongue portion and the leading edge of the blade of the turbine impeller.

[0106] (8) In some embodiments, the turbine housing according to any one of (1) to (7) above further includes:

[0107] a second scroll flow path (for example, the scroll flow path 16 ( 16A or 16B) described above) for supplying the working gas to the turbine impeller; and

[0108] The second tongue portion (for example, the tongue portion 20 ( 20A or 20B) described above) is formed at the position of the outlet (for example, the outlet E1 or E2 described above) of the second scroll flow path.

[0109] According to the turbine housing described in (8) above, by providing at least one inclined portion at the inner end edge of the first tongue portion, noise that tends to occur in a turbine including two or more scroll flow paths can be effectively suppressed.

[0110] (9) In some embodiments, in the turbine housing described in (8) above,

[0111] The second tongue portion includes an inner edge (for example, the inner edge 24 described above), the inner edge facing the leading edge of the blade of the turbine impeller with the radial gap therebetween in a cross section along the axial direction,

[0112] The inner end edge of the second tongue portion includes at least one inclined portion inclined with respect to the axial direction.

[0113] According to the turbine housing described in (9), since the inner edge of the second tongue portion includes at least one inclined portion inclined relative to the axial direction, the gap between the inner edge of the second tongue portion and the leading edge of the blade of the turbine impeller changes according to the axial position within the range where the at least one inclined portion is formed. Therefore, the intensity of the vortex generated by the second tongue portion can be weakened, and the generation of noise caused by the interference between the vortex generated by the second tongue portion and the leading edge of the blade of the turbine impeller can be suppressed. Therefore, the noise of the vortex flow path that is prone to become a problem in a turbine including more than two roots can be effectively suppressed.

[0114] (10) In some embodiments, in the turbine housing described in (9) above,

[0115] The inner end edge of the first tongue portion includes a first inclined portion, the first inclined portion extending in a radially outer direction from the hub side in the axial direction toward the shroud side, the inner end edge of the second tongue portion includes a second inclined portion (for example, the inclined portions 26, 26a, 26b, 26c, 26d, 26e described above), the second inclined portion extending in a radially inner direction from the hub side in the axial direction toward the shroud side,

[0116] The range in the axial direction where the first inclined portion is provided at least partially overlaps with the range in the axial direction where the second inclined portion is provided.

[0117] According to the turbine housing described in (10), by setting the inclination direction of the first inclined portion and the inclination direction of the second inclined portion in opposite directions in at least a part of the axial direction, the strength or direction of the eddy current generated by the first tongue portion and the strength or direction of the eddy current generated by the second tongue portion can be dispersed at the same position in the axial direction, and the noise caused by the eddy current generated by the first tongue portion and the noise caused by the eddy current generated by the second tongue portion can be suppressed from mutually reinforcing. Thus, a turbine housing capable of realizing a turbine with excellent quietness can be provided.

[0118] (11) In some embodiments, in the turbine housing described in (9) or (10) above, when a gap between the inner edge of the first tongue portion and the leading edge of a blade of the turbine impeller and a gap between the inner edge of the second tongue portion and the leading edge of a blade of the turbine impeller are compared at the same position in the axial direction, the gap between the inner edge of the first tongue portion and the leading edge of the blade of the turbine impeller (for example, Figure 8 The gap d between the inner edge 24 of the tongue portion 20A shown and the leading edge 12LE of the blade 12 and the gap between the inner edge of the second tongue portion and the leading edge of the blade of the turbine impeller (for example, Figure 8 The gap d) between the inner end edge 24 of the tongue portion 20B and the leading edge 12LE of the blade 12 shown is different over at least a part of the range in the axial direction.

[0119] According to the turbine housing described in (11), by making the gap between the inner edge of the first tongue portion and the leading edge of the blade of the turbine impeller and the gap between the inner edge of the second tongue portion and the leading edge of the blade of the turbine impeller different in at least a part of the axial direction, the strength or direction of the vortex generated in the first tongue portion and the strength or direction of the vortex generated in the second tongue portion can be dispersed at the same position in the axial direction, and the noise caused by the vortex generated in the first tongue portion and the noise caused by the vortex generated in the second tongue portion can be suppressed from mutually reinforcing. Thus, a turbine housing capable of realizing a turbine with excellent quietness can be provided.

[0120] (12) A turbine according to at least one embodiment of the present invention includes a turbine impeller (for example, the turbine impeller 6 ) and the turbine casing described in (1) above.

[0121] According to the turbine described in (12), the turbine housing described in (1) can effectively suppress the generation of noise caused by the interference between the vortex generated by the tongue portion and the leading edge of the blade of the turbine impeller. Thus, a turbine housing capable of realizing a turbine with excellent quietness can be provided.

[0122] (13) A turbocharger according to at least one embodiment of the present invention includes the turbine described in (12) above.

[0123] According to the turbocharger described in (13), the turbine described in (12) can effectively suppress the generation of noise caused by the interference between the vortex generated by the tongue portion and the leading edge of the blade of the turbine impeller. Therefore, a turbocharger capable of realizing a turbine with excellent quietness can be provided.

[0124] Explanation of symbols

[0125] 2-turbocharger, 4-turbine, 6-turbine impeller, 8-turbine housing, 10-hub, 12-blades, 12LE-leading edge, 12t-front end, 14-shroud, 15-exhaust channel, 16, 16A, 16B-vortex flow path, 16A1, 16A2, 16B1, 16B2-flow path wall, 20, 20A, 20B-tongue, 21h, 21s-wall surface, 22-outer end edge, 24-inner end edge, 25, 25a, 25b, 25c-parallel portion, 26, 26a, 26b, 26c, 26d, 26e-inclined portion, 28-convex shape, 29-concave shape.

Claims

1. A turbine housing, which accommodates at least a portion of a turbine impeller, the turbine housing comprising: a first swirl flow path for supplying working gas to the turbine impeller; and The first tongue portion is formed at the exit of the first scroll flow path. The first tongue portion includes an inner end edge, the inner end edge facing the leading edge of a blade of the turbine impeller with a gap in the radial direction of the turbine impeller interposed therebetween in a cross section along the axial direction of the turbine impeller, The inner end edge includes at least one inclined portion inclined relative to the axial direction, If the size of the range in the axial direction where the front edge is provided is A, and the total size of the range in the axial direction where the at least one inclined portion is provided is B, the inner edge is configured to satisfy B≥0.2A.

2. The turbine housing according to claim 1, wherein: The inner end edge includes a first inclined portion that is inclined toward an outer side in the radial direction as it moves from a hub side toward a shroud side of the turbine impeller in the axial direction.

3. The turbine housing according to claim 1, wherein: The inner end edge includes a first inclined portion that is inclined toward the inner side in the radial direction as it moves from the hub side of the turbine impeller toward the shroud side in the axial direction.

4. The turbine housing according to claim 2 or 3, wherein: The first inclined portion is formed over the entire inner edge.

5. The turbine housing according to claim 2 or 3, wherein: The inner end edge includes a parallel portion parallel to the axial direction.

6. The turbine housing according to claim 1, wherein: The inner end edge includes: a first inclined portion, which is inclined toward the outer side in the radial direction as it moves from the hub side of the turbine impeller in the axial direction toward the shroud side; and a second inclined portion, which is inclined toward the inner side in the radial direction as it moves from the hub side of the turbine impeller in the axial direction toward the shroud side.

7. The turbine housing according to claim 1, wherein: If the minimum value of the gap between the inner edge and the leading edge is dmin, the maximum value of the gap between the inner edge and the leading edge is dmax, and the diameter of the turbine impeller is D, Then dmin / D≥0.02 and dmax / D≤0.09 are satisfied.

8. The turbine housing according to claim 1, further comprising: a second scroll flow path for supplying working gas to the turbine impeller; and The second tongue portion is formed at a position of an outlet of the second scroll flow path.

9. The turbine housing according to claim 8, wherein: The second tongue portion includes an inner end edge, and the inner end edge is opposed to a leading edge of a blade of the turbine impeller with the radial gap therebetween in a cross section along the axial direction. In a cross section along the axial direction, the inner end edge of the second tongue portion includes at least one inclined portion inclined with respect to the axial direction.

10. The turbine housing according to claim 9, wherein: The inner end edge of the first tongue portion includes a first inclined portion, the first inclined portion extending in a radially outer direction from the hub side in the axial direction toward the shroud side, and the inner end edge of the second tongue portion includes a second inclined portion extending in a radially inner direction from the hub side in the axial direction toward the shroud side. The range in the axial direction where the first inclined portion is provided at least partially overlaps with the range in the axial direction where the second inclined portion is provided.

11. The turbine housing according to claim 9 or 10, wherein: If the gap between the inner end edge of the first tongue portion and the leading edge of the blade of the turbine impeller and the gap between the inner end edge of the second tongue portion and the leading edge of the blade of the turbine impeller are compared at the same position in the axial direction, the gap between the inner end edge of the first tongue portion and the leading edge of the blade of the turbine impeller and the gap between the inner end edge of the second tongue portion and the leading edge of the blade of the turbine impeller are different in at least a part of the range in the axial direction. 12 . A turbine comprising a turbine impeller and the turbine casing according to claim 1 .

13. A turbocharger comprising the turbine according to claim 12.

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