TURBINE HOUSING, TURBINE AND TURBOCHARGER

Abstract

A turbine housing accommodates at least a portion of a turbine wheel, the turbine housing comprising a first screw flow path for supplying a working gas to the turbine wheel and a first tongue section formed at a position of an outlet of the first screw flow path, wherein in a cross-section along an axial direction of the turbine wheel the first tongue section includes an inner end edge facing a leading edge of a blade of the turbine wheel, wherein a clearance is inserted in a radial direction of the turbine wheel between the inner end edge and the leading edge, the inner end edge includes at least one inclined section inclined with respect to the axial direction, and in a case where a size of a region in which the leading edge is provided in the axial direction is designated as A and a sum of sizes of a region,in which each of which at least one inclined section in the axial direction is designated as B, the inner end edge is configured such that it satisfies B ≥ 0.2A.

Description

Technical area

[0001] The present disclosure relates to a turbine housing, a turbine and a turbocharger. State of the art

[0002] PTL 1 discloses a twin-scroll turbocharger in which two scroll flow paths are formed that supply exhaust gas to a turbine wheel. Furthermore, PTL 1 discloses a turbocharger including three scroll flow paths. Citation listPatent literature

[0003] [PTL 1] US Patent Application Publication No. 2015-0345433 Summary of the inventionTechnical problem

[0004] However, in a turbocharger turbine, a vortex generated at a position of a tongue portion formed at a position of an outlet of the scroll flow path may interfere with the blades of the turbine wheel, generating noise. This phenomenon occurs even when the number of scroll flow paths is one, but especially when the number of scroll flow paths is two or more, the rotation of the turbine fluctuates due to a difference in flow efficiency at the outlet of each scroll flow path, and noise is likely to increase.

[0005] In view of the above circumstances, an object of at least one embodiment of the present disclosure is to provide a turbine housing capable of realizing a turbine with excellent quietness, and a turbine and a turbocharger including the turbine housing. Solution to the problem

[0006] To achieve the above object, a turbine housing according to at least one embodiment of the present disclosure is a turbine housing that houses at least a portion of a turbine wheel, the turbine housing comprising: a first screw flow path for supplying a working gas to the turbine wheel; and a first tongue portion formed at a position of an outlet of the first screw flow path, wherein, in a cross section along an axial direction of the turbine wheel, the first tongue portion includes an inner end edge facing a leading edge of a blade of the turbine wheel, wherein a clearance is inserted in a radial direction of the turbine wheel between the inner end edge and the leading edge, the inner end edge includes at least one inclined portion inclined with respect to the axial direction, and in a case where a size of an area where the leading edge is provided in the axial direction is denoted as A and a sum of sizes of an area where each of the at least one inclined portion is provided in the axial direction is denoted as B, the inner end edge is configured to satisfy B ≥ 0.2A.

[0007] To achieve the above object, a turbine according to at least one embodiment of the present disclosure includes a turbine wheel; and the turbine housing described above.

[0008] To achieve the above object, a turbocharger according to at least one embodiment of the present disclosure includes the turbine described above. Advantageous Effects of the Invention

[0009] According to at least one embodiment of the present disclosure, a turbine housing capable of realizing a turbine with excellent quietness, and a turbine and a turbocharger including the turbine housing are provided. Brief description of the drawings Fig. 1 is a schematic cross-sectional view schematically illustrating an example of a cross section perpendicular to an axial direction of a turbine 4 of a turbocharger 2 according to an embodiment. Fig. 2 is a schematic sectional view showing an example of a HH cross section and an example of a II cross section of Fig. 1 represents. Fig. 3 is a schematic sectional view showing another example of the HH cross section and another example of the II cross section of Fig. 1 represents. Fig. 4 is a schematic sectional view showing yet another example of the HH cross section and yet another example of the II cross section of Fig. 1 represents. Fig. 5 is a schematic sectional view showing yet another example of the HH cross section and yet another example of the II cross section of Fig. 1 represents. Fig. 6 is a schematic sectional view showing yet another example of the HH cross section and yet another example of the II cross section of Fig. 1 represents. Fig. Fig. 7 is a schematic sectional view showing an example of a cross section along the axial direction defined by each of a tongue portion 20A, a rotation axis line O and a tongue portion 20B in the embodiment shown in Fig. 1, represents the turbine 4 shown. Fig. Fig. 8 is a schematic sectional view showing an example of a cross section along the axial direction defined by each of a tongue portion 20A, a rotation axis line O and a tongue portion 20B in the embodiment shown in Fig. 1, represents the turbine 4 shown. Fig. 9 is a schematic sectional view showing yet another example of the HH cross section and yet another example of the II cross section of Fig. 1. Description of embodiments

[0010] Some embodiments of the present disclosure will be described below with reference to the accompanying drawings. Dimensions, materials, shapes, relative arrangements, and the like of components described as embodiments or illustrated in the drawings are not intended to limit the scope of the invention, but are merely illustrative examples.

[0011] For example, expressions representing relative or absolute arrangements, such as "in a certain direction", "along a certain direction", "parallel", "perpendicular", "center", "concentric", or "coaxial", not only strictly represent the arrangements, but also a state in which the arrangements are relatively shifted with a tolerance or by an angle or distance, as long as the same function can be obtained.

[0012] For example, expressions that represent things being in a same state, such as "identical," "equal," and "homogeneous," represent not only strictly a same state, but also a state in which a difference exists with a tolerance or to such an extent that the same function can be obtained.

[0013] For example, expressions representing shapes such as a quadrangular shape and a cylindrical shape represent not only shapes such as a quadrangular shape and a cylindrical shape in a geometrically strict sense, but also shapes including an uneven portion or a chamfer portion within a range where the same effect can be obtained.

[0014] Furthermore, expressions such as “provided with,” “equipped with,” “containing,” or “having” a component are not exclusionary expressions that exclude the presence of other components.

[0015] Fig. 1 is a schematic cross-sectional view schematically illustrating an example of a cross section perpendicular to an axial direction of a turbine 4 of a turbocharger 2 according to an embodiment. Fig. 2 is a schematic sectional view showing an example of a HH cross section and an example of a II cross section of Fig. 1. Note that the HH cross section described above is a cross section (meridian plane of the turbine 4) along the axial direction at the turbine 4, and further specifically, it is a cross section passing through a tongue portion 20A, which will be described below, including a rotational axis line O of a turbine wheel 6. Moreover, the II cross section described above is a cross section (meridian plane of the turbine 4) along the axial direction at the turbine 4, and further specifically, it is a cross section passing through a tongue portion 20B, which will be described below, including the rotational axis line O of the turbine wheel 6.

[0016] It should be noted that in the present description, unless otherwise specified, the "axial direction" means the axial direction of the turbocharger 2, that is, the axial direction of the turbine wheel 6 of the turbine 4, the "radial direction" means the radial direction of the turbocharger 2, that is, the radial direction of the turbine wheel 6 of the turbine 4, and the "circumferential direction" means the circumferential direction of the turbocharger 2, that is, the circumferential direction of the turbine wheel 6 of the turbine 4.

[0017] The Fig. 1 and Fig. The turbocharger 2 shown in Figure 2 may be, for example, a turbocharger for an automobile and includes the turbine 4 and a compressor (not shown). The turbine 4 is a radial turbine including the turbine wheel 6 and a turbine housing 8 that houses the turbine wheel 6. The turbine wheel 6 is connected to an impeller of a compressor (not shown) via a rotating shaft (not shown) and is configured to rotate integrally with the turbine wheel 6 and the impeller.

[0018] The turbine housing 8 contains a casing 14 (see Fig. 2), a screw flow path 16A (see Fig. 1) and a screw flow path 16B (see Fig. 1).

[0019] As in Fig. For example, as shown in Figure 2, the turbine wheel 6 includes a hub 10 and a plurality of blades 12 provided on an outer peripheral surface of the hub 10 at intervals in the circumferential direction. The shroud 14 is arranged to face leading edges 12t of the plurality of blades 12 via a clearance and, with respect to the hub 10, forms an exhaust passage 15 through which exhaust gas from an engine (not shown) passes. The exhaust gas from the engine functions as a working gas for rotating the turbine wheel 6.

[0020] For example, as in Fig. 1, the scroll flow path 16A and the scroll flow path 16B are each configured to guide the exhaust gas of the engine to the turbine wheel 6. The scroll flow path 16A and the scroll flow path 16B are connected to the exhaust passage 15 at different regions in the circumferential direction on an outer peripheral side of the turbine wheel 6 (in the case of Fig. 1 shown example areas which are shifted from each other by 180 degrees in the circumferential direction) and are formed around the rotation axis line O of the turbine wheel 6 in a vortex shape.

[0021] For example, as in Fig. 1, the turbine housing 8 has the tongue portion 20A having a tongue shape (projection shape) formed by a portion in which a flow path wall 16A1 on an inner side in the radial direction in the scroll flow path 16A and a flow path wall 16B2 on an outer side in the radial direction in the scroll flow path 16B are connected to each other, at a position of an outlet E1 of the scroll flow path 16A. Furthermore, the turbine housing 8 includes the tongue portion 20B having a tongue shape (projection shape) formed by a portion in which a flow path wall 16B1 on the inner side in the radial direction in the scroll flow path 16B and a flow path wall 16A2 on the outer side in the radial direction in the scroll flow path 16A are connected to each other, at a position of an outlet E2 of the scroll flow path 16B.

[0022] Hereinafter, examples of shapes of the tongue portion 20A and the tongue portion 20B will be described with reference to Fig. 2 to 6. Some using Fig. The embodiments described in Figures 2 to 6 can be applied to the configuration of the HH cross-section and the configuration of the II cross-section described in Fig. 1 are applied or can be applied to both configurations. In a case where the description of some in Fig. 2 to 6 is interpreted as the description of the HH cross section, in the following description, the "screw flow path 16" means the "screw flow path 16A", and the "tongue portion 20" in the following description means the "tongue portion 20A". In a case where the description of some in Fig. 2 to 6 is interpreted as the description of the II cross section, in the following description, the "screw flow path 16" means the "screw flow path 16B", and the "tongue portion 20" in the following description means the "tongue portion 20B".

[0023] In the Fig. 2, the tongue portion 20 is formed from a wall surface 21h on the side of the hub 10 (compressor side) in the scroll flow path 16 to a wall surface 21s on the side of the shroud 14 in the scroll flow path 16 and includes an outer end edge 22, which is an edge of the tongue portion 20 on the outside in the radial direction, and an inner end edge 24, which is an edge of the tongue portion 20 on the inside in the radial direction. In the illustrated example, the outer end edge 22 is formed to be parallel to the axial direction. Moreover, the inner end edge 24 faces a leading edge 12LE of the blade 12 of the turbine wheel 6, with a clearance d in the radial direction interposed therebetween. In the cross-section shown in Fig. 2, the leading edge 12LE of the blade 12 of the turbine wheel 6 extends parallel to the axial direction along the axial direction.

[0024] In the Fig. 2, the inner end edge 24 includes at least one inclined portion 26 which is inclined with respect to the axial direction. Fig. 2, the inner end edge 24 is formed only by an inclined portion 26 which is inclined in a cross section along the axial direction with respect to the axial direction, and the inclined portion 26 extends linearly from the side of hub 10 to the side of shell 14 in the axial direction to the outside in the radial direction. In the embodiment shown in Fig. 2, the inclined portion 26 is formed over the entire inner end edge 24 from the wall surface 21h on the side of hub 10 in the screw flow path 16 to the wall surface 21s on the side of shroud 14 in the screw flow path 16.

[0025] In the Fig. 2, in a case where a size of an area where the leading edge 12LE is provided in the axial direction is denoted as A and a size of an area where the inclined portion 26 is provided in the axial direction is denoted as B, the inner end edge 24 is formed to satisfy B ≥ 0.2A. Moreover, in the illustrated example, the inner end edge 24 is formed to satisfy B ≥ 0.5 and B ≥ 0.8.

[0026] In addition, the Fig. 2, in a case where a minimum value of the clearance d between the inner end edge 24 and the leading edge 12LE is denoted as dmin, a maximum value of the clearance d between the inner end edge 24 and the leading edge 12LE is denoted as dmax, and a diameter of the turbine wheel 6 is denoted as D, the inner end edge 24 is formed to satisfy dmin / D ≥ 0.02 and dmax / D ≤ 0.09.

[0027] With the Fig. 2, since the inner end edge 24 of the tongue portion 20 includes the inclined portion 26 inclined with respect to the axial direction, the clearance d between the inner end edge 24 of the tongue portion 20 and the leading edge 12LE of the blade 12 of the turbine wheel 6 in a region where the inclined portion 26 is formed in the axial direction is changed in accordance with the position in the axial direction. Therefore, it is possible to reduce the strength of the vortex generated by the tongue portion 20 and to suppress the generation of noise caused by interference between the vortex generated by the tongue portion 20 and the leading edge 12LE of the blade 12.

[0028] Furthermore, by satisfying B ≥ 0.2A in one half or more of a region A where the leading edge 12LE of the blade 12 is provided in the axial direction, the clearance d between the inner end edge 24 of the tongue portion 20 and the leading edge 12LE of the blade 12 is changed in accordance with the position in the axial direction. Therefore, it is possible to effectively reduce the strength of the vortex generated by the tongue portion 20, and it is possible to effectively suppress the generation of noise caused by interference between the vortex generated by the tongue portion 20 and the leading edge 12LE of the blade 12. Accordingly, it is possible to provide the turbine housing 8 capable of realizing the turbine 4 with excellent quietness.Moreover, since the inclined portion 26 is formed over the entire inner end edge 24, it is possible to suppress the generation of noise caused by interference between the vortex generated by the tongue portion 20 and the leading edge 12LE of the blade 12 while suppressing the complexity of the shape of the tongue portion 20.

[0029] Furthermore, as the clearance 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 tends to improve, but the noise tends to increase. However, as described above, by satisfying dmin / D ≥ 0.02 and dmax / D ≤ 0.09, it is possible to suppress an increase in noise caused by interference between the vortex generated by the tongue portion 20 and the leading edge 12LE of the blade 12 while achieving good performance of the turbine 4.

[0030] Fig. 3 is a schematic sectional view showing another example of the HH cross section and another example of the II cross section of Fig. 1 represents.

[0031] At the Fig. 3, in the cross section along the axial direction, the inclined portion 26 of the inner end edge 24 of the tongue portion 20 is inclined with respect to the axial direction and extends linearly from the side of the hub 10 to the side of the casing 14 in the axial direction to the inside in the radial direction. In the Fig. 3, the inclined portion 26 is formed over the entire inner end edge 24 from the wall surface 21h on the side of the hub 10 at the screw flow path 16 to the wall surface 21s on the side of the casing 14 at the screw flow path 16. Also in the cross section shown in Fig. 3, the leading edge 12LE of the blade 12 of the turbine wheel 6 extends parallel to the axial direction along the axial direction.

[0032] In the Fig. 3, in a case where a size of an area in which the leading edge 12LE is provided in the axial direction is designated as A and a size of an area in which the inclined portion 26 is provided in the axial direction is designated as B, the inner end edge 24 is formed to satisfy B ≥ 0.2A. Moreover, in the illustrated example, the inner end edge 24 is formed to satisfy B ≥ 0.5 and B ≥ 0.8. Moreover, also in the example shown in Fig. 3, although not shown, in a case where a minimum value of the clearance between the inner end edge 24 and the leading edge 12LE is denoted as dmin, a maximum value of the clearance between the inner end edge 24 and the leading edge 12LE is denoted as dmax, and a diameter of the turbine wheel 6 is denoted as D, the inner end edge 24 is formed to satisfy dmin / D ≥ 0.02 and dmax / D ≤ 0.09.

[0033] Also in the Fig. 3, in a region where the inclined portion 26 is formed in the axial direction, the clearance d between the inner end edge 24 of the tongue portion 20 and the leading edge 12LE of the blade 12 of the turbine wheel 6 is changed in accordance with the position in the axial direction. Therefore, it is possible to reduce the intensity of the vortex generated by the tongue portion 20 and suppress the generation of noise caused by interference between the vortex generated by the tongue portion 20 and the leading edge 12LE of the blade 12. Moreover, by satisfying B≥0.2A, it is possible to effectively reduce the intensity of the vortex generated by the tongue portion 20 and effectively suppress the generation of noise caused by interference between the vortex generated by the tongue portion 20 and the leading edge 12LE of the blade 12.Accordingly, it is possible to provide the turbine casing capable of realizing the turbine with excellent quietness. Furthermore, by satisfying dmin / D ≥ 0.02 and dmax / D ≤ 0.09, it is possible to suppress an increase in noise caused by interference between the vortex generated by the tongue portion 20 and the leading edge 12LE of the blade 12 while achieving good performance of the turbine 4. Furthermore, since the inclined portion 26 is formed over the entire inner end edge 24, it is possible to suppress the generation of noise caused by interference between the vortex generated by the tongue portion 20 and the leading edge 12LE of the blade 12 while suppressing the complexity of the shape of the tongue portion 20.

[0034] Fig. 4 is a schematic sectional view showing yet another example of the HH cross section and yet another example of the II cross section of Fig. 1 represents.

[0035] At the Fig. 4, the inner end edge 24 of the tongue portion 20 includes, in the cross section along the axial direction, a parallel portion 25 parallel to the axial direction and the inclined portion 26 inclined with respect to the axial direction. In the embodiment shown in Fig. 4, one end of the parallel section 25 is connected to the wall surface 21h on the side of the hub 10 in the screw flow path 16, and the other end of the parallel section 25 is connected to one end of the inclined section 26. The other end of the inclined section 26 is connected to the wall surface 21s on the side of the casing 14 in the screw flow path 16. In the cross section shown in Fig. 4, the inclined portion 26 extends linearly from the side of hub 10 to the side of casing 14 in the axial direction to the outside in the radial direction. Also in the cross-section shown in Fig. 4, the leading edge 12LE of the blade 12 of the turbine wheel 6 extends parallel to the axial direction along the axial direction.

[0036] In the Fig. 4, in a case where a size of an area in which the leading edge 12LE is provided in the axial direction is designated as A and a size of an area in which the inclined portion 26 is provided in the axial direction is designated as B, the inner end edge 24 is formed to satisfy B ≥ 0.2A. In addition, also in the cross section shown in Fig. 4, although not shown, in a case where a minimum value of the clearance between the inner end edge 24 and the leading edge 12LE is denoted as dmin, a maximum value of the clearance between the inner end edge 24 and the leading edge 12LE is denoted as dmax, and a diameter of the turbine wheel 6 is denoted as D, the inner end edge 24 is formed to satisfy dmin / D ≥ 0.02 and dmax / D ≤ 0.09.

[0037] With the Fig. 4, in a region where the inclined portion 26 is formed in the axial direction, the clearance d between the inner end edge 24 of the tongue portion 20 and the leading edge 12LE of the blade 12 of the turbine wheel 6 is changed in accordance with the position in the axial direction. Therefore, it is possible to reduce the intensity of the vortex generated by the tongue portion 20 and to suppress the generation of noise caused by interference between the vortex generated by the tongue portion 20 and the leading edge 12LE of the blade 12. Moreover, by satisfying B≥0.2A, it is possible to effectively reduce the intensity of the vortex generated by the tongue portion 20 and to effectively suppress the generation of noise caused by interference between the vortex generated by the tongue portion 20 and the leading edge 12LE of the blade 12.Accordingly, it is possible to provide a turbine casing capable of realizing the turbine with excellent quietness. Furthermore, by satisfying dmin / D ≥ 0.02 and dmax / D ≤ 0.09, it is possible to suppress an increase in noise caused by interference between the vortex generated by the tongue portion 20 and the leading edge 12LE of the blade 12, while achieving good performance of the turbine 4.

[0038] Fig. 5 is a schematic sectional view showing yet another example of the HH cross section and yet another example of the II cross section of Fig. 1 represents.

[0039] At the Fig. 5, the inner end edge 24 of the tongue portion 20 has, in the cross-section along the axial direction, a convex shape 28 that projects inward in the radial direction. In the embodiment shown in Fig. 5, the inner end edge 24 of the tongue portion 20 includes the parallel portion 25 parallel to the axial direction, an inclined portion 26 inclined with respect to the axial direction, and an inclined portion 26b inclined with respect to the axial direction. In the cross section shown in Fig. 5, one end of the inclined portion 26a is connected to the wall surface 21h on the hub 10 side of the screw flow path 16, and the other end of the inclined portion 26a is connected to one end of the parallel portion 25. Furthermore, 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 shell 14 side of the screw flow path 16. In the cross section shown in Fig. 5, the inclined portion 26a extends linearly from the side of hub 10 to the side of casing 14 in the axial direction toward the inside in the radial direction, and the inclined portion 26b extends linearly from the side of hub 10 to the side of casing 14 in the axial direction toward the outside in the radial direction. Also in the cross-section shown in Fig. 5, the leading edge 12LE of the blade 12 of the turbine wheel 6 extends parallel to the axial direction along the axial direction.

[0040] In the Fig. 5, in a case where a size of an area where the leading edge 12LE is provided in the axial direction is denoted as A, a size of an area where the inclined portion 26a is provided in the axial direction is denoted as b1, a size of an area where the inclined portion 26b is provided in the axial direction is denoted as b2, and a sum of the size b1 of the area where the inclined portion 26a is provided in the axial direction and the size b2 of the area where the inclined portion 26b is provided in the axial direction is denoted as B (= b1 + b2), the inner end edge 24 is formed to satisfy B ≥ 0.2A. Moreover, also in the cross section shown in Fig. 5, although not shown, in a case where a minimum value of the clearance between the inner end edge 24 and the leading edge 12LE is denoted as dmin, a maximum value of the clearance between the inner end edge 24 and the leading edge 12LE is denoted as dmax, and a diameter of the turbine wheel 6 is denoted as D, the inner end edge 24 is formed to satisfy dmin / D ≥ 0.02 and dmax / D ≤ 0.09.

[0041] At the Fig. 5, in the region where the inclined portion 26a is formed in the axial direction, the clearance d between the inner end edge 24 of the tongue portion 20 and the leading edge 12LE of the blade 12 can be reduced from the hub 10 side to the shroud 14 side in the axial direction. Moreover, in the region where the inclined portion 26b is formed in the axial direction, the clearance d between the inner end edge 24 of the tongue portion 20 and the leading edge 12LE of the blade 12 can be increased from the hub 10 side to the shroud 14 side in the axial direction.In this way, by narrowing or widening the clearance d between the inner end 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, it is possible to effectively reduce the intensity of the vortex generated by the tongue portion 20, and it is possible to effectively suppress the generation of noise caused by interference between the vortex generated by the tongue portion 20 and the leading edge 12LE of the blade 12. Moreover, by satisfying B≥0.2A, it is possible to effectively reduce the intensity of the vortex generated by the tongue portion 20, and it is possible to effectively suppress the generation of noise caused by interference between the vortex generated by the tongue portion 20 and the leading edge 12LE of the blade 12.Furthermore, by satisfying dmin / D ≥ 0.02 and dmax / D ≤ 0.09, it is possible to suppress an increase in noise caused by interference between the vortex generated by the tongue portion 20 and the leading edge 12LE of the blade 12 while achieving good performance of the turbine 4.

[0042] Fig. 6 is a schematic sectional view showing yet another example of the HH cross section and yet another example of the II cross section of Fig. 1 represents.

[0043] At the Fig. 6, in the cross section along the axial direction, the inner end edge 24 of the tongue portion 20 includes two convex shapes 28 protruding inward in the radial direction, the two convex shapes 28 are formed to be aligned with each other in the axial direction, and a concave shape 29 is formed between the two convex shapes 28 in the axial direction.

[0044] At the Fig. 6, the inner end edge 24 of the tongue portion 20 includes, in the cross section along the axial direction, parallel portions 25a, 25b, and 25c that are parallel to the axial direction, and inclined portions 26a, 26b, 26c, and 26d that are inclined with respect to the axial direction. In the embodiment shown in Fig. 6, one end of the inclined portion 26a is connected to the wall surface 21h on the hub 10 side of the scroll flow path 16, and the other end of the inclined portion 26a is connected to one end of the parallel portion 25a. Furthermore, 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. Furthermore, 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 side of shell 14 in the screw flow path 16.

[0045] In the Fig. 6, the inclined portion 26a extends linearly from the hub 10 side to the shell 14 side in the axial direction toward the inner side in the radial direction, and the inclined portion 26b extends linearly from the hub 10 side to the shell 14 side in the axial direction toward the outer side in the radial direction. Furthermore, the inclined portion 26c extends linearly from the hub 10 side to the shell 14 side in the axial direction toward the inner side in the radial direction, and the inclined portion 26d extends linearly from the hub 10 side to the shell 14 side in the axial direction toward the outer side in the radial direction. Also in the cross section shown in Fig. 6, the leading edge 12LE of the blade 12 of the turbine wheel 6 extends parallel to the axial direction along the axial direction.

[0046] In the Fig. 6 is a cross-sectional view in a case where a size of an area where the leading edge 12LE is provided in the axial direction is denoted as A, a size of an area where the inclined portion 26a is provided in the axial direction is denoted as b1, a size of an area where the inclined portion 26b is provided in the axial direction is denoted as b2, a size of an area where the inclined portion 26c is provided in the axial direction is denoted as b3, a size of an area where the inclined portion 26d is provided in the axial direction is denoted as b4, and a sum of the size b1 of the area where the inclined portion 26a is provided in the axial direction, the size b2 of the area where the inclined portion 26b is provided in the axial direction, the size b3 of the area where the inclined portion 26c is provided in the axial direction, and the size b4 of the area,in which the inclined portion 26d is provided in the axial direction is denoted as B (= b1 + b2 + b3 + b4), the inner end edge 24 is formed to satisfy B ≥ 0.2A. In addition, also in the embodiment shown in , Fig. 6, in a case where a minimum value of the clearance between the inner end edge 24 and the leading edge 12LE is denoted as dmin, a maximum value of the clearance between the inner end edge 24 and the leading edge 12LE is denoted as dmax, and a diameter of the turbine wheel 6 is denoted as D, the inner end edge 24 is formed to satisfy dmin / D ≥ 0.02 and dmax / D ≤ 0.09.

[0047] At the Fig. 6, the effect obtained by widening or narrowing the clearance d between the inner end edge 24 of the tongue portion 20 and the leading edge 12LE of the blade 12 from the side of hub 10 to the side of shroud 14 in the axial direction (the effect of reducing the strength of the vortex generated by the tongue portion 20) can be increased compared to the configuration shown in Fig. 5, it is possible to further enhance the strength of the vortex generated by the tongue portion 20 and the leading edge 12LE of the blade 12, and it is possible to effectively suppress the generation of noise caused by interference between the vortex generated by the tongue portion 20 and the leading edge 12LE of the blade 12. Moreover, by satisfying B≥0.2A, it is possible to effectively reduce the strength of the vortex generated by the tongue portion 20, and it is possible to effectively suppress the generation of noise caused by interference between the vortex generated by the tongue portion 20 and the leading edge 12LE of the blade 12. Moreover, by satisfying dmin / D≥0.02 and dmax / D≤0.09, it is possible to suppress an increase in noise caused by interference between the vortex generated by the tongue portion 20 and the leading edge 12LE of the blade 12, while achieving good performance of the turbine 4.

[0048] Fig. Fig. 7 is a schematic sectional view showing an example of a cross section along the axial direction defined by each of a tongue portion 20A, a rotation axis line O and a tongue portion 20B in the embodiment shown in Fig. 1, represents the turbine 4 shown.

[0049] At the Fig. In the exemplary embodiment shown in Figure 7, the tongue portion 20A has the same configuration as that shown in Fig. 2, and the tongue portion 20B has the same configuration as that shown in Fig. 3 shown configuration. In the Fig. 7, in the cross section along the axial direction, the inner end edge 24 of the tongue portion 20A includes the inclined portion 26d extending from the side of the hub 10 to the side of the shroud 14 in the axial direction toward the outside in the radial direction, and the inner end edge 24 of the tongue portion 20B includes an inclined portion 26e extending from the side of the hub 10 to the side of the shroud 14 in the axial direction toward the inside in the radial direction. Also in the Fig. In the cross section shown in Figure 7, the leading edge 12LE of the blade 12 of the turbine wheel 6 extends parallel to the axial direction along the axial direction. Furthermore, a region where the inclined portion 26d is provided in the axial direction overlaps with at least a part of a region where the inclined portion 26e is provided in the axial direction (in the illustrated example, the entire region where the inclined portion 26e is provided in the axial direction).

[0050] At the Fig. In the turbine 4 shown in Fig. 7, by setting the inclination direction of the inclined portion 26d and the inclination direction of the inclined portion 26e to be opposite to each other, the strength, direction, and the like of the vortex generated in the tongue portion 20A and the strength, direction, and the like of the vortex generated in the tongue portion 20B can be made uneven at the same position in the axial direction, and it is possible to suppress the amplification of the noise caused by the vortex generated in the tongue portion 20A and the noise caused by the vortex generated in the tongue portion 20B. Accordingly, it is possible to provide the turbine housing 8 capable of realizing the turbine 4 with excellent quietness.

[0051] Fig. Fig. 8 is a schematic sectional view showing an example of a cross section along the axial direction defined by each of a tongue portion 20A, a rotation axis line O and a tongue portion 20B in the embodiment shown in Fig. 1, represents the turbine 4 shown.

[0052] At the Fig. 8, the tongue portion 20A and the tongue portion 20B each have the same configuration as the one shown in Fig. 4 shown tongue section 20. In the Fig. 8, in the cross section along the axial direction, in a case where the clearance d between the inner end edge 24 of the tongue portion 20A and the leading edge 12LE of the blade 12 and the clearance d between the inner end edge 24 of the tongue portion 20B and the leading edge 12LE of the blade 12 at the same position in the axial direction are compared, the clearance d between the inner end edge 24 of the tongue portion 20A and the leading edge 12LE of the blade 12 and the clearance d between the inner end edge 24 of the tongue portion 20B and the leading edge 12LE of the blade 12 are different from each other in at least a part of a region (in the illustrated example, the entire region in which the inner end edge 24 of the tongue portion 20A is formed in the axial direction) in the axial direction.

[0053] In the Fig. 8, the inner end edge 24 of the tongue portion 20A and the inner end edge 24 of the tongue portion 20B each include the parallel portion 25 parallel to the axial direction and the inclined portion 26 inclined with respect to the axial direction. Also in the cross section shown in Fig. In the cross-section shown in Figure 8, the leading edge 12LE of the blade 12 of the turbine wheel 6 extends parallel to the axial direction along the axial direction. Here, the clearance d between the parallel section 25 of the tongue section 20A and the leading edge 12LE of the blade 12 is greater than the clearance d between the parallel section 25 of the tongue section 20B and the leading edge 12LE of the blade 12.Moreover, in a case where the clearance d between the inclined portion 26 of the tongue portion 20A and the leading edge 12LE of the blade 12 is compared with the clearance 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, in the entire range where the inclined portion 26 of the tongue portion 20A is formed in the axial direction, the clearance d between the inclined portion 26 of the tongue portion 20A and the leading edge 12LE of the blade 12 is larger than the clearance d between the inclined portion 26 of the tongue portion 20B and the leading edge 12LE of the blade 12.

[0054] At the Fig. 8, by making the clearance d between the inner end edge 24 of the tongue portion 20A and the leading edge 12LE of the blade 12 and the clearance d between the inner end edge 24 of the tongue portion 20B and the leading edge 12LE of the blade 12 different from each other at least in a part of the range in the axial direction, the strength, direction, and the like of the vortex generated in the tongue portion 20A and the strength, direction, and the like of the vortex generated in the tongue portion 20B can be made uneven at the same position in the axial direction, and it is possible to suppress the amplification of the noise caused by the vortex generated in the tongue portion 20A and the noise caused by the vortex generated in the tongue portion 20B. Accordingly, it is possible to provide the turbine casing 8 capable of realizing the turbine 4 with excellent quietness.

[0055] Fig. 9 is a schematic sectional view showing yet another example of the HH cross section and yet another example of the II cross section of Fig. 1 represents.

[0056] At the Fig. 9, the inner end edge 24 of the tongue portion 20 in the cross section along the axial direction has the concave shape 29, which is concave to the outside in the radial direction. In the embodiment shown in Fig. 9, the inner end edge 24 of the tongue portion 20 includes the parallel portion 25 parallel to the axial direction, an inclined portion 26f inclined with respect to the axial direction, and an inclined portion 26g inclined with respect to the axial direction. In the cross section shown in Fig. 9, one end of the inclined portion 26f is connected to the wall surface 21h on the hub 10 side of the screw flow path 16, and the other end of the inclined portion 26f is connected to one end of the parallel portion 25. Furthermore, 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 shell 14 side of the screw flow path 16. In the cross section shown in Fig. 9, the inclined portion 26f extends linearly from the side of hub 10 to the side of casing 14 in the axial direction toward the outside in the radial direction, and the inclined portion 26g extends linearly from the side of hub 10 to the side of casing 14 in the axial direction toward the inside in the radial direction. Also in the cross section shown in Fig. 9, the leading edge 12LE of the blade 12 of the turbine wheel 6 extends parallel to the axial direction along the axial direction.

[0057] In the Fig. 9, in a case where a size of an area where the leading edge 12LE is provided in the axial direction is denoted as A, a size of an area where the inclined portion 26f is provided in the axial direction is denoted as b1, a size of an area where the inclined portion 26g is provided in the axial direction is denoted as b2, and a sum of the size b1 of the area where the inclined portion 26f is provided in the axial direction and the size b2 of the area where the inclined portion 26g is provided in the axial direction is denoted as B (= b1 + b2), the inner end edge 24 is formed to satisfy B ≥ 0.2A. Moreover, also in the cross section shown in Fig. 9, although not shown, in a case where a minimum value of the clearance between the inner end edge 24 and the leading edge 12LE is denoted as dmin, a maximum value of the clearance between the inner end edge 24 and the leading edge 12LE is denoted as dmax, and a diameter of the turbine wheel 6 is denoted as D, the inner end edge 24 is formed to satisfy dmin / D ≥ 0.02 and dmax / D ≤ 0.09.

[0058] At the Fig. 9, in the region where the inclined portion 26f is formed in the axial direction, the clearance d between the inner end edge 24 of the tongue portion 20 and the leading edge 12LE of the blade 12 can be increased from the hub 10 side to the shroud 14 side in the axial direction. Moreover, in the region where the inclined portion 26g is formed in the axial direction, the clearance d between the inner end edge 24 of the tongue portion 20 and the leading edge 12LE of the blade 12 can be reduced from the hub 10 side to the shroud 14 side in the axial direction.In this way, by widening or narrowing the clearance d between the inner end 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, it is possible to effectively reduce the intensity of the vortex generated by the tongue portion 20, and it is possible to effectively suppress the generation of noise caused by interference between the vortex generated by the tongue portion 20 and the leading edge 12LE of the blade 12. Moreover, by satisfying B≥0.2A, it is possible to effectively reduce the intensity of the vortex generated by the tongue portion 20, and it is possible to effectively suppress the generation of noise caused by interference between the vortex generated by the tongue portion 20 and the leading edge 12LE of the blade 12.Furthermore, by satisfying dmin / D ≥ 0.02 and dmax / D ≤ 0.09, it is possible to suppress an increase in noise caused by interference between the vortex generated by the tongue portion 20 and the leading edge 12LE of the blade 12 while achieving good performance of the turbine 4.

[0059] The present disclosure is not limited to the above-described embodiments, and also includes a form in which modifications are added to the above-described embodiments, or a form in which the embodiments are appropriately combined with each other.

[0060] For example, in some embodiments described above, the configuration in which the turbine 4 includes the two scroll flow paths 16A and 16B is exemplified, but the number of scroll flow paths 16 provided in the turbine 4 may be one, three or more.

[0061] For example, contents described in each embodiment described above are understood as follows.

[0062] (1) A turbine housing (for example, the turbine housing 8 described above) according to at least one embodiment of the present disclosure is a turbine housing that houses at least a part of a turbine wheel (for example, the turbine wheel 6 described above), the turbine housing comprising: a first scroll flow path (for example, the above-described scroll flow path 16 (16A or 16B)) for supplying a working gas to the turbine wheel; and a first tongue portion (for example, the above-described tongue portion 20 (20A or 20B)) formed at a position of an outlet (for example, the above-described outlet E1 or E2) of the first screw flow path, wherein, in a cross section along an axial direction of the turbine wheel, the first tongue portion includes an inner end edge (for example, the above-described inner end edge 24) facing a leading edge (for example, the above-described leading edge 12LE) of a blade (for example, the above-described blade 12) of the turbine wheel, wherein a clearance (for example, the above-described clearance d) is inserted in a radial direction of the turbine wheel between the inner end edge and the leading edge, the inner end edge includes at least one inclined portion (for example, the above-described inclined portions 26, 26a, 26b, 26c, 26d and 26e) inclined with respect to the axial direction, and in a case where a size of an area where the leading edge is provided in the axial direction is denoted as A and a sum of sizes of an area where each of the at least one inclined portion is provided in the axial direction is denoted as B, the inner end edge is configured to satisfy B ≥ 0.2A.

[0063] With the turbine housing according to (1), since the inner end edge of the first tongue portion includes at least one inclined portion inclined with respect to the axial direction, the clearance between the inner end edge of the first tongue portion and the leading edge of the blade of the turbine wheel in a region where the at least one inclined portion is formed is changed in accordance with the position in the axial direction. Therefore, it is possible to reduce the intensity of the vortex generated by the first tongue portion and to 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 wheel.

[0064] Furthermore, by satisfying B ≥ 0.2A in one half or more of a region where the leading edge of the blade of the turbine wheel is provided in the axial direction, the clearance between the inner end edge of the first tongue portion and the leading edge of the blade of the turbine wheel is changed in accordance with the position in the axial direction. Therefore, it is possible to effectively reduce the strength of the vortex generated by the first tongue portion, and it is possible to effectively suppress the generation of noise caused by interference between the vortex generated by the tongue portion and the leading edge of the blade of the turbine wheel. Accordingly, it is possible to provide the turbine housing capable of realizing the turbine with excellent quietness.

[0065] (2) In some embodiments, the turbine housing according to (1) includes the inner end edge has a first inclined portion (for example, the inclined portion 26 which is Fig. 2 and Fig. 4, the inclined section 26b, which is shown in Fig. 5, the inclined sections 26b and 26d, which are shown in Fig. 6, the inclined section 26d, which in Fig. 7, and the inclined section 26, which is shown in Fig. 8) which is inclined from a side of hub of the turbine wheel to a side of shroud in the axial direction to an outside in the radial direction.

[0066] With the turbine housing according to (2), in the region where the first inclined portion is formed in the axial direction, the clearance between the inner end edge of the first tongue portion and the leading edge of the blade of the turbine wheel can be increased from the hub side to the shroud side in the axial direction. Therefore, it is possible to reduce the intensity of the vortex generated by 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 wheel. Therefore, it is possible to provide the turbine housing capable of realizing the turbine with excellent quietness. (3) In some embodiments, the turbine housing according to (1) includes the inner end edge has a first inclined portion (for example, the inclined portion 26 which is Fig. 3, the inclined section 26a, which in Fig. 5, the inclined sections 26a and 26c, which in Fig. 6, and the inclined section 26e, which is shown in Fig. 7) which is inclined from a side of hub of the turbine wheel to a side of shroud in the axial direction to an inner side in the radial direction.

[0067] With the turbine casing according to (3), in the region where the first inclined portion is formed in the axial direction, the clearance between the inner end edge of the first tongue portion and the leading edge of the blade of the turbine wheel can be reduced from the hub side to the shroud side in the axial direction. Therefore, it is possible to reduce the intensity of the vortex generated by the first tongue portion, and it is possible to 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 wheel. Therefore, it is possible to provide the turbine casing capable of realizing the turbine with excellent quietness.

[0068] (4) In some embodiments, in the turbine housing according to (2) or (3), the first inclined section is formed over the entire inner end edge.

[0069] With the turbine casing according to (4), it is possible to 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 wheel, while suppressing the complication of the shape of the first tongue portion.

[0070] (5) In some embodiments, the turbine housing according to (2) or (3) includes: the inner end edge has a parallel section (for example, the parallel sections 25, 25a, 25b and 25c described above) which is parallel to the axial direction.

[0071] With the turbine casing according to (5), it is possible to 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 wheel, while suppressing the complication of the shape of the first tongue portion.

[0072] (6) In some embodiments, the turbine housing according to (1) includes the inner end edge has a first inclined portion (for example, the inclined portion 26b shown in Fig. 5, the inclined sections 26b and 26d, which are shown in Fig. 6) which is inclined from a side of the hub of the turbine wheel to a side of the shroud in the axial direction to an outside in the radial direction, and a second inclined portion (for example, the inclined portion 26a shown in Fig. 5, the inclined sections 26a and 26c, which in Fig. 6) which is inclined from the hub side of the turbine wheel to the shroud side in the axial direction to an inner side in the radial direction.

[0073] With the turbine housing according to (6), in the region where the first inclined portion is formed in the axial direction, the clearance between the inner end edge of the first tongue portion and the leading edge of the blade of the turbine wheel from the hub side to the shroud side in the axial direction can be increased. Furthermore, in the region where the second inclined portion is formed in the axial direction, the clearance between the inner end edge of the first tongue portion and the leading edge of the blade of the turbine wheel from the hub side to the shroud side in the axial direction can be reduced.In this way, by widening or narrowing the clearance between the inner end edge of the first tongue portion and the leading edge of the blade of the turbine wheel from the hub side to the shroud side in the axial direction, it is possible to effectively reduce the strength of the vortex generated by the first tongue portion, and it is possible to effectively 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 wheel.

[0074] (7) In some embodiments, the turbine housing according to any one of (1) to (6), in a case where a minimum value of the clearance between the inner end edge and the leading edge is denoted as dmin, a maximum value of the clearance between the inner end edge and the leading edge is denoted as dmax, and a diameter of the turbine wheel is denoted as D, dmin / D ≥ 0.02 and dmax / D ≤ 0.09 are satisfied.

[0075] When the clearance between the inner end edge of the first tongue portion and the leading edge of the turbine wheel blade is reduced, turbine performance improves, but noise tends to increase. In this regard, with the turbine casing according to (7), by satisfying dmin / D ≥ 0.02 and dmax / D ≤ 0.09, it is possible to suppress an increase in noise caused by interference between the vortex generated by the first tongue portion and the leading edge of the turbine wheel blade while achieving good turbine performance.

[0076] (8) In some embodiments, the turbine housing according to any one of (1) to (7) further comprises: a second scroll flow path (for example, the above-described scroll flow path 16 (16A or 16B)) for supplying a working gas to the turbine wheel; and a second tongue portion (for example, the above-described tongue portion 20 (20A or 20B)) formed at a position of an outlet (for example, the above-described outlet E1 or E2) of the second scroll flow path.

[0077] With the turbine casing according to (8), by providing at least one inclined portion at the inner end edge of the first tongue portion, it is possible to effectively suppress the noise which is likely to be a problem in the turbine including two or more scroll flow paths.

[0078] (9) In some embodiments, the turbine housing according to (8) contains in a cross-section along the axial direction, the second tongue portion has an inner end edge (for example, the above-described inner end edge 24) facing a leading edge of a blade of the turbine wheel, with a clearance in the radial direction being inserted between the inner end edge and the leading edge, and the inner end edge of the second tongue portion includes at least one inclined portion inclined with respect to the axial direction.

[0079] With the turbine casing according to (9), since the inner end edge of the second tongue portion includes at least one inclined portion inclined with respect to the axial direction, the clearance between the inner end edge of the second tongue portion and the leading edge of the blade of the turbine wheel in a region where the at least one inclined portion is formed is changed in accordance with the position in the axial direction. Therefore, it is possible to reduce the intensity of the vortex generated by the second tongue portion and suppress the generation of noise caused by interference between the vortex generated by the second tongue portion and the leading edge of the blade of the turbine wheel. Therefore, it is possible to effectively suppress noise, which is likely to be a problem in the turbine including two or more scroll flow paths.

[0080] (10) In some embodiments, the turbine housing according to (9) includes the inner end edge of the first tongue portion has a first inclined portion extending from a side of the hub to a side of the casing in the axial direction to an outside in the radial direction, the inner end edge of the second tongue portion includes a second inclined portion (for example, the above-described inclined portions 26, 26a, 26b, 26c, 26d and 26e) extending from the hub side to the shell side in the axial direction to an inner side in the radial direction, and a region in which the first inclined portion is provided in the axial direction overlaps with at least a part of a region in which the second inclined portion is provided in the axial direction.

[0081] With the turbine casing according to (10), by setting the inclination direction of the first inclined portion and the inclination direction of the second inclined portion to be opposite to each other in at least a part of a range in the axial direction, the strength, direction, and the like of the vortex generated in the first tongue portion and the strength, direction, and the like of the vortex generated in the second tongue portion can be made uneven at the same position in the axial direction, and it is possible to suppress the amplification of 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. Accordingly, it is possible to provide the turbine casing capable of realizing the turbine with excellent quietness.

[0082] (11) In some embodiments, the turbine housing according to (9) or (10) differs, In a case where the clearance between the inner end edge of the first tongue portion and the leading edge of the blade of the turbine wheel is compared with the clearance between the inner end edge of the second tongue portion and the leading edge of the blade of the turbine wheel at the same position in the axial direction, the clearance (for example, the clearance d between the inner end edge 24 of the tongue portion 20A and the leading edge 12LE of the blade shown in Fig. 8) between the inner end edge of the first tongue section and the leading edge of the blade of the turbine wheel and the clearance (for example, the clearance d between the inner end edge 24 of the tongue section 20B and the leading edge 12LE of the blade shown in Fig.8) between the inner end edge of the second tongue portion and the leading edge of the blade of the turbine wheel in at least a part of an area in the axial direction.

[0083] With the turbine casing according to (11), by making the clearance between the inner end edge of the first tongue portion and the leading edge of the blade of the turbine wheel and the clearance between the inner end edge of the second tongue portion and the leading edge of the blade of the turbine wheel different from each other at least in a part of the range in the axial direction, the strength, direction, and the like of the vortex generated in the first tongue portion and the strength, direction, and the like of the vortex generated in the second tongue portion can be made uneven at the same position in the axial direction, and it is possible to suppress the amplification of 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.Accordingly, it is possible to provide the turbine casing capable of realizing the turbine with excellent quietness.

[0084] (12) A turbine according to at least one embodiment of the present disclosure includes a turbine wheel (for example, the turbine wheel 6 described above); and the turbine housing according to (1).

[0085] With the turbine according to (12), since the turbine casing according to (1) is provided, it is possible to effectively suppress the generation of noise caused by interference between the vortex generated by the tongue portion and the leading edge of the blade of the turbine wheel. Accordingly, it is possible to provide the turbine casing capable of realizing the turbine with excellent quietness.

[0086] (13) A turbocharger according to at least one embodiment of the present disclosure comprises the turbine according to (12).

[0087] With the turbocharger according to (13), since the turbine housing according to (12) is provided, it is possible to effectively suppress the generation of noise caused by interference between the vortex generated by the tongue portion and the leading edge of the blade of the turbine wheel. Accordingly, it is possible to provide the turbocharger capable of realizing the turbine with excellent quietness. List of reference symbols 2 turbochargers 4 turbines 6 Turbine wheel 8 turbine housings 10 Hub 12 shovels 12LE front edge 12t leading edge 14 Sheathing 15 exhaust duct 16, 16A, 16B Screw flow path 16A1, 16A2, 16B1, 16B2 flow path wall 20, 20A, 20B tongue section 21h, 21s wall surface 22 outer end edge 24 inner end edge 25, 25a, 25b, 25c parallel section 26, 26a, 26b, 26c, 26d, 26e inclined section 28 convex shape 29 concave shape

Claims

[1] Turbine housing accommodating at least a portion of a turbine wheel, the turbine housing comprising: a first screw flow path for supplying a working gas to the turbine wheel; and a first tongue portion formed at a position of an outlet of the first screw flow path, wherein, in a cross section along an axial direction of the turbine wheel, the first tongue portion includes an inner end edge facing a leading edge of a blade of the turbine wheel, wherein a clearance is inserted in a radial direction of the turbine wheel between the inner end edge and the leading edge, the inner end edge includes at least one inclined portion inclined with respect to the axial direction, and in a case where a size of an area where the leading edge is provided in the axial direction is denoted as A and a sum of sizes of an area where each of the at least one inclined portion is provided in the axial direction is denoted as B, the inner end 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 inclined from a hub side of the turbine wheel to a shroud side in the axial direction to an outer side in the radial direction. [3] The turbine housing according to claim 1, wherein the inner end edge includes a first inclined portion inclined from a hub side of the turbine wheel to a shroud side in the axial direction to an inner side in the radial direction. [4] A turbine casing according to claim 2 or 3, wherein the first inclined portion is formed over the entire inner end edge. [5] A turbine casing 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 inclined from a hub side of the turbine wheel to a shroud side in the axial direction to an outer side in the radial direction, and a second inclined portion inclined from the hub side of the turbine wheel to the shroud side in the axial direction to an inner side in the radial direction. [7] The turbine casing according to claim 1, wherein in a case where a minimum value of the clearance between the inner end edge and the leading edge is denoted as dmin, a maximum value of the clearance between the inner end edge and the leading edge is denoted as dmax, and a diameter of the turbine wheel is denoted as D, dmin / D ≥ 0.02 and dmax / D ≤ 0.09 are satisfied. [8] Turbine housing according to claim 1, further comprising: a second screw flow path for supplying a working gas to the turbine wheel; and a second tongue portion formed at a position of an outlet of the second scroll flow path. [9] A turbine casing according to claim 8, wherein, in a cross section along the axial direction, the second tongue portion includes an inner end edge facing a leading edge of a blade of the turbine wheel, a clearance being inserted in the radial direction between the inner end edge and the leading edge, and 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] Turbine housing according to claim 9, wherein the inner end edge of the first tongue portion includes a first inclined portion extending from a side of the hub to a side of the casing in the axial direction to an outside in the radial direction, the inner end edge of the second tongue portion includes a second inclined portion extending from the hub side to the shell side in the axial direction to an inner side in the radial direction, and a region in which the first inclined portion is provided in the axial direction overlaps with at least a part of a region in which the second inclined portion is provided in the axial direction. [11] Turbine housing according to claim 9 or 10, wherein, in a case where the clearance between the inner end edge of the first tongue portion and the leading edge of the blade of the turbine wheel is compared with the clearance between the inner end edge of the second tongue portion and the leading edge of the blade of the turbine wheel at the same position in the axial direction, the clearance between the inner end edge of the first tongue portion and the leading edge of the blade of the turbine wheel and the clearance between the inner end edge of the second tongue portion and the leading edge of the blade of the turbine wheel differ from each other in at least a part of a range in the axial direction. [12] Turbine, comprising: a turbine wheel; and the turbine housing according to claim 1. [13] A turbocharger comprising the turbine according to claim 12.