Turbine wheel, turbine and turbocharger

Abstract

A turbine wheel of at least one embodiment is a turbine wheel coupled to a rotating shaft and rotating around an axis, the turbine wheel having: a hub having a hub face inclined with respect to the axis in a cross section along the axis; and a plurality of blades provided at the hub face. The turbine wheel includes a plurality of flow paths formed between adjacent two blades, and in a case where an area of a throat of at least one flow path of the plurality of flow paths is set as Aen and an average area of the throats of the plurality of flow paths is set as Aave, a relationship of Aen / Aave > 1.01 is satisfied.

Description

Technical Field

[0001] This disclosure relates to a turbine impeller, a turbine, and a turbocharger. This application claims priority based on Japanese Patent Application No. 2020-152425 filed with the Japanese Patent Office on September 10, 2020, the contents of which are incorporated herein by reference. Background Technology

[0002] Centrifugal or mixed-flow turbines have a vortex section for causing exhaust gas to flow in radially (see, for example, Patent Document 1).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2018-123802 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] When a vortex section is incorporated, a tongue section is required in its design. Therefore, as exhaust gas flows, a boundary layer is generated on the surface of the tongue section, creating a wake (low-speed region). The low-speed exhaust gas flows into the turbine, potentially reducing turbine efficiency.

[0008] In view of the above, at least one embodiment of this disclosure aims to suppress the reduction in turbine efficiency.

[0009] Solution for solving the problem

[0010] (1) In at least one embodiment of the present disclosure, a turbine impeller is connected to a rotating shaft and rotates about an axis, the turbine impeller comprising:

[0011] A hub having a hub surface that is inclined relative to the axis in a cross section along the axis;

[0012] Multiple blades are disposed on the hub surface;

[0013] The turbine impeller includes multiple flow paths formed between two adjacent blades.

[0014] Let Aen be the area of ​​the throat of the expanded flow path, which is the throat of at least one of the plurality of flow paths.

[0015] When the average area of ​​the throats of the multiple flow paths is set to Aave,

[0016] The relationship Aen / Aave > 1.01 is satisfied.

[0017] (2) The turbine of at least one embodiment of the present disclosure has a turbine impeller with the structure described in (1) above.

[0018] (3) The turbocharger of at least one embodiment of the present disclosure has a turbine with the structure described in (2) above.

[0019] Invention Effects

[0020] According to at least one embodiment of this disclosure, it is possible to suppress the reduction in turbine efficiency. Attached Figure Description

[0021] Figure 1 This is a cross-sectional view illustrating one example of a turbocharger with several embodiments.

[0022] Figure 2 This is a perspective view of the appearance of a turbine impeller in several implementations.

[0023] Figure 3 This is a diagram illustrating the vortex section of a turbine in several embodiments.

[0024] Figure 4A It is a diagram used to illustrate the velocity triangle.

[0025] Figure 4B It is a diagram used to illustrate the velocity triangle.

[0026] Figure 5 This is a schematic unfolded diagram of a turbine impeller with several implementation methods.

[0027] Figure 6 This is a schematic unfolded diagram of a turbine impeller with several implementation methods.

[0028] Figure 7 This is a schematic unfolded view of a turbine impeller according to another embodiment.

[0029] Figure 8 This is a schematic unfolded view of a turbine impeller according to another embodiment. Detailed Implementation

[0030] Hereinafter, several embodiments of the present disclosure will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, and relative arrangements of the constituent components described as embodiments or shown in the drawings are not intended to limit the scope of the present disclosure, but are merely illustrative examples.

[0031] For example, expressions indicating relative or absolute configurations such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric" or "coaxial" not only precisely indicate such configurations, but also indicate the state of relative displacement by angle or distance with tolerances or the degree to which the same function can be obtained.

[0032] For example, expressions indicating that things are "the same", "equal" and "homogeneous" are equal not only indicate a state of strict equality, but also indicate a state of difference where there is a tolerance or a degree of difference in the ability to achieve the same function.

[0033] For example, expressions representing shapes such as quadrilaterals or cylinders not only refer to shapes in a strictly geometric sense, but also include shapes with concave or convex parts or chamfers within the range that can achieve the same effect.

[0034] On the other hand, expressions such as “possessing,” “equipped,” “having,” “including,” or “having” a constituent element are not exclusive expressions that exclude the existence of other constituent elements.

[0035] (Overall structure of turbocharger 1)

[0036] Figure 1 This is a cross-sectional view showing one example of a turbocharger 1 with several implementations.

[0037] The turbocharger 1 in several embodiments is an exhaust turbocharger used to boost the intake air of an engine mounted in a vehicle such as a car.

[0038] The turbocharger 1 includes a turbine impeller 3 connected to a rotor shaft 2 as a rotation axis, a compressor impeller 4, a housing (turbine casing) 5 that rotatably houses the turbine impeller 3, and a housing (compressor casing) 6 that rotatably houses the compressor impeller 4. Furthermore, the turbine casing 5 includes a vortex section 7 having an internal vortex flow path 7a. The compressor casing 6 includes a vortex section 8 having an internal vortex flow path 8a.

[0039] Several embodiments of the turbine 30 include a turbine impeller 3 and a housing 5. Several embodiments of the compressor 40 include a compressor impeller 4 and a housing 6.

[0040] (Turbine impeller 3)

[0041] Figure 2 This is a perspective view of the appearance of the turbine impeller 3 in several embodiments.

[0042] Several embodiments of the turbine impeller 3 are impellers connected to the rotor shaft (rotating shaft) 2 and rotating about the rotation axis AXw. Several embodiments of the turbine impeller 3 include: a hub 31 having a hub surface 32 inclined relative to the rotation axis AXw in a section along the rotation axis AXw; and a plurality of blades (moving blades) 33 disposed on the hub surface 32. It should be noted that... Figure 1 , Figure 2 The turbine impeller 3 shown is a radial flow turbine, but it could also be a mixed flow turbine. Figure 2In the diagram, arrow R indicates the direction of rotation of the turbine impeller 3. Multiple blades 33 are arranged at intervals around the turbine impeller 3.

[0043] In several embodiments of the turbine impeller 3, a throat 35 is formed with the smallest flow path area between two circumferentially adjacent blades 33 (see below). Figure 5 It should be noted that in several embodiments of the turbine impeller 3, the throat 35 is formed in the region on the ventral side of the blade 33 that is closer to the leading edge 36 than the trailing edge 37 of the blade.

[0044] It should be noted that although the perspective view is omitted, the compressor impeller 4 of several embodiments also has the same structure as the turbine impeller 3 of several embodiments. That is, the compressor impeller 4 of several embodiments is an impeller connected to the rotor shaft (rotation shaft) 2 and rotating about the rotation axis AXw. The compressor impeller 4 of several embodiments has: a hub 41, which has a hub surface 42 that is inclined relative to the rotation axis AXw in a section along the rotation axis AXw; and a plurality of blades (moving blades) 43, which are disposed on the hub surface 42. The blades 43 are arranged at intervals in the circumferential direction of the compressor impeller 4.

[0045] In this turbocharger 1, exhaust gas, which serves as the working fluid, flows from the leading edge 36 of the turbine impeller 3 toward the trailing edge 37. This causes the turbine impeller 3 to rotate, and also causes the compressor impeller 4 of the compressor 40, which is connected via the rotor shaft 2, to rotate. As a result, the intake gas flowing in from the inlet 40a of the compressor 40 is compressed by the compressor impeller 4 as it flows from the leading edge 46 of the compressor impeller 4 toward the trailing edge 47.

[0046] (Regarding the effect of the wake generated at the tongue 71)

[0047] Figure 3 This is a diagram illustrating the vortex section 7 of the turbine 30 in several embodiments, and is a schematic cross-sectional view of a section orthogonal to the rotation axis AXw.

[0048] Figure 4A It is a diagram used to illustrate the velocity triangle when the inflow angle β of the exhaust gas at the leading edge 36 of the turbine impeller 3 is close to the ideal inflow angle.

[0049] Figure 4B It is a diagram used to illustrate the velocity triangle when the inflow angle β of the exhaust gas at the leading edge 36 of the turbine impeller 3 deviates from the ideal inflow angle.

[0050] Figure 4A The velocity triangle shown is formed by the rotational velocity vector U of the turbine impeller 3, the absolute velocity vector C of the exhaust gas, and the relative velocity vector W of the exhaust gas as observed from the turbine impeller 3.

[0051] Figure 4B The velocity triangle shown is formed by the rotational velocity vector U of the turbine impeller 3, the absolute velocity vector C' of the exhaust gas, and the relative velocity vector W of the exhaust gas as viewed from the turbine impeller 3.

[0052] exist Figure 4A In the velocity triangle shown, the inflow angle β of the exhaust gas at the leading edge 36 of the turbine impeller 3 is the angle difference between the extension direction of the blade rib line CL of the blade 33 at the leading edge 36 and the relative velocity vector W.

[0053] exist Figure 4B In the velocity triangle shown, the inflow angle β' of the exhaust gas at the leading edge 36 of the turbine impeller 3 is the angle difference between the extension direction of the blade rib line CL of the blade 33 at the leading edge 36 and the relative velocity vector W.

[0054] It should be noted that, in Figure 4A as well as Figure 4B In the diagram, the surface below blade 33 is the pressure surface PS, and the surface above it is the negative pressure surface SS.

[0055] In addition, Figure 4A as well as Figure 4B In the middle, the arc of the single-dot dashed line is the trajectory Loc of the leading edge 36 that moves by the rotation of the turbine impeller 3.

[0056] In several embodiments, the turbine housing 5 has a tongue 71 that separates the vortex flow path 7a from the flow path 9 which is radially outward from the vortex flow path 7a.

[0057] Generally, in turbine 30, the closer the inflow angle β of the exhaust gas at the leading edge 36 of turbine impeller 3 is to the ideal inflow angle, the better the aerodynamic performance of turbine 30. However, if a boundary layer forms on the surface of tongue 71 during exhaust gas flow, generating a wake (low-speed region), the absolute velocity of the exhaust gas decreases, and the magnitude of the absolute velocity vector C of the exhaust gas becomes smaller. Therefore, if the inflow angle β of the exhaust gas at the leading edge 36 of turbine impeller 3 deviates from the ideal inflow angle, it may lead to a decrease in the efficiency of turbine 30.

[0058] Figure 5 as well as Figure 6 This is a schematic unfolded view of the turbine impeller 3 according to several embodiments. It should be noted that... Figure 5 In the diagram, the distance P between two adjacent blades 33 is defined as a fixed region. Figure 6 The middle section is a magnified view of the area containing the localized blade spacing.

[0059] like Figure 5 as well as Figure 6As shown, a flow path 12 for exhaust gas is formed between two adjacent blades 33 along the circumferential direction of the turbine impeller 3. Several embodiments of the turbine impeller 3 include multiple flow paths 12 formed between two adjacent blades 33. Each of the multiple flow paths 12 has a throat 35, which is the part of the flow path 12 with the smallest cross-sectional area (flow path area) when viewed along the direction of exhaust gas flow.

[0060] exist Figure 5 as well as Figure 6 In the diagram, the ellipse with dashed lines represents the approximate location of the throat 35.

[0061] Typically, the flow rate of turbine 30 depends on the area A of throat 35 (the flow path area at throat 35), and the larger the area A of throat 35, the greater the flow rate. Therefore, in order to suppress the decrease in absolute velocity of exhaust gas caused by the aforementioned wake, it is possible to increase the amount of exhaust gas flowing through flow path 12 by increasing the area A of throat 35 in a portion of flow path 12.

[0062] Therefore, in several embodiments of the turbine impeller 3, the area Aen of the throat 35A of the throat-enlarging flow path 12A, which is at least one of the multiple flow paths 12, is intentionally made larger than the average area Aave of the throats 35 of the multiple flow paths 12. Specifically, in several embodiments of the turbine impeller 3, the area Aen of the throat 35A of the throat-enlarging flow path 12A is set in such a way that Aen / Aave > 1.01.

[0063] It should be noted that the above average area Aave is the average of the flow path areas at the throats 35 and 35A of all flow paths 12, including the throat enlargement flow path 12A.

[0064] In the above structure, the area Aen of the throat 35A in the throat enlargement flow path 12A is more than 1.01 times the average area Aave of the throats 35 of the multiple flow paths 12.

[0065] Typically, the manufacturing error of the area A of the throat 35 is less than 1% of the average area Aave of the throat 35. Therefore, by intentionally making the throat 35A in the flow path 12A larger than the average area Aave of the throats 35 of the multiple flow paths 12, the area Aen of the throat 35 is made to exceed 1.01 times the aforementioned average area Aave.

[0066] According to the turbine impeller 3 of the above-described embodiments, the exhaust gas flows easily in the throat-enlarged flow path 12A. Therefore, even if a wake occurs as described above, the decrease in the absolute velocity of the exhaust gas can be suppressed, and the deviation of the exhaust gas inflow angle β at the leading edge 36 of the turbine impeller 3 from the ideal inflow angle can be suppressed. Thus, in the turbine 30 equipped with the turbine impeller 3 of the above-described embodiments, the decrease in the efficiency of the turbine 30 can be suppressed.

[0067] (The case of increasing the area Aen of the throat 35A by adjusting the blade spacing)

[0068] In several embodiments of the turbine impeller 3, the relationship Pen > Pave may be satisfied when the blade spacing between two adjacent blades 33 forming the throat expansion flow path 12A is set as Pen, and the average value of the blade spacing P of the plurality of blades 33 is set as Pave.

[0069] It should be noted that the above average value Pave is the average value of all blade spacing P, including the blade spacing Pen of two adjacent blades 33 forming the throat enlarged flow path 12A.

[0070] Therefore, by making the blade spacing Pen of the two adjacent blades 33 forming the throat expansion flow path 12A larger than the average value Pave of the blade spacing P, it is relatively easy to make the area Aen of the throat 35A in the throat expansion flow path 12A larger than the average area Aave.

[0071] (The case where the area Aen of the throat 35A is increased by increasing the blade thickness T)

[0072] Figure 7 This is a schematic unfolded view of the turbine impeller 3 according to another embodiment.

[0073] exist Figure 7 In the turbine impeller 3 shown, the blade thickness in the region forming the throat 35A of at least one of the two adjacent blades 33 forming the throat expansion flow path 12A is set as Ten, and the average value of the blade thickness T in the region forming the throat 35 of the plurality of blades 33 is set as Tave, thus satisfying the relationship Ten < Tave.

[0074] It should be noted that the above average value Tave is the average value of the blade thickness T in the region forming the throat 35, 35A of all blades 33, including the two adjacent blades 33 forming the throat enlargement flow path 12A.

[0075] That is, in Figure 7 In the turbine impeller 3 shown, in at least one of the two adjacent blades 33A that form the throat expansion flow path 12A, the blade thickness Ten in the region forming the throat 35A is made smaller than the blade thickness T of the other blades 33, thereby making the area Aen of the throat 35A larger than the average area Aave mentioned above.

[0076] Therefore, it is relatively easy to make the area Aen of the throat in the throat expansion flow path larger than the average area Aave mentioned above.

[0077] It should be noted that, as Figure 7 As shown in the turbine impeller 3, the blade thickness of one of the two adjacent blades 33 forming the throat expansion flow path 12A can be reduced as a whole from the leading edge 36 to the trailing edge 37, or the blade thickness can be reduced only in the region forming the throat 35A.

[0078] (The case of increasing the area Aen of the throat 35A by changing the shape of the wheel hub surface)

[0079] Figure 8 This is a schematic unfolded view of the turbine impeller 3 in another embodiment.

[0080] exist Figure 8 In the turbine impeller 3 shown, in the meridional plane of the turbine impeller 3, the span distance between the hub surface 32 in the throat 35A of the throat-enlarged flow path 12A and the tip 34 of the blade 33 is defined as Hen. In the meridional plane of the turbine impeller 3, the average value of the span distance H between the hub surface 32 in the throat 35 of the multiple flow paths 12 and the tip 34 of the blade 33 is defined as Have. Moreover, the relationship Hen > Have can also be satisfied.

[0081] It should be noted that the above average value Have is the average blade span distance H of the hub surface 32 and the end 34 of the blade 33 in all throats 35 and 35A, including throat 35A, of the throat enlarged flow path 12A.

[0082] exist Figure 8 In the turbine impeller 3 shown, the area A of the throat 35 can be changed by altering the span distance H between the hub surface 32 and the tip 34 of the blade 33. For example, in Figure 8 In the turbine impeller 3 shown, the hub surface 32 in the throat 35A that expands the throat flow path 12A is more concave radially inward than the hub surface 32 in the throat 35 of other flow paths 12. As a result, the aforementioned blade span distance Hen in the throat 35A that expands the throat flow path 12A is larger than the average blade span distance H Have, thus increasing the area Aen of the throat 35A.

[0083] In this way, by making the blade span distance Hen between the hub surface 32 and the end 34 in the throat 35A of the throat expansion flow path 12A larger than the average blade span distance H Have, it is relatively easy to make the area Aen of the throat 35A in the throat expansion flow path 12A larger than the average area Aave.

[0084] (Configuration of throat enlarged flow path 12A)

[0085] In the turbine impeller 3 of the above-described embodiments, at least one throat enlargement flow path 12A may also include multiple throat enlargement flow paths 12A.

[0086] The appropriate value for the number of throat enlargement flow paths 12A varies depending on, for example, the specifications of the turbocharger 1 or the specifications of the combined engine.

[0087] In the turbine impeller 3 of the above-described embodiments, if multiple throat enlargement flow paths 12A are included, multiple throat enlargement flow paths 12A are provided instead of one, which is effective in further suppressing the reduction in efficiency of the turbine 30.

[0088] In the turbine impeller 3 of the above-described embodiments, multiple throat enlargement flow paths 12A can also be configured discretely.

[0089] Whether it is better to arrange the multiple throat enlargement flow paths 12A continuously along the circumference or discretely, for example, depends on the specifications of the turbocharger 1 and the combined engine.

[0090] In the turbine impeller 3 of the above-described embodiments, if multiple throat enlargement flow paths 12A are discretely configured, it is effective in cases where multiple throat enlargement flow paths 12A are discretely configured.

[0091] In the turbine impeller 3 of the above-described embodiments, multiple throat enlargement flow paths 12A can also be continuously configured.

[0092] As mentioned above, it is better to arrange the multiple throat enlargement flow paths 12A continuously along the circumference or discretely, for example, depending on the specifications of the turbocharger 1 and the combined engine.

[0093] In the turbine impeller 3 of the above-described embodiments, if multiple throat enlargement flow paths 12A are continuously arranged, it is effective in cases where multiple throat enlargement flow paths 12A are continuously arranged.

[0094] In the turbine 30 of the above embodiments, since any one of the turbine impellers 3 of the above embodiments is provided, the reduction in efficiency of the turbine 30 can be suppressed.

[0095] Furthermore, in the turbocharger 1 of the above-described embodiments, since it is equipped with the turbine 30 of the above-described embodiments, the performance of the turbocharger 1 can be improved.

[0096] This disclosure is not limited to the above-described embodiments, but also includes modifications to the above-described embodiments and appropriate combinations of these modifications.

[0097] The contents described in the above embodiments can be understood, for example, as follows.

[0098] (1) The turbine impeller 3 of at least one embodiment of the present disclosure is a turbine impeller 3 connected to a rotating shaft (rotor shaft 2) and rotating about an axis (rotation axis AXw). The turbine impeller 3 includes: a hub 31 having a hub surface 32 that is inclined relative to the axis (rotation axis Axw) in a cross section along the axis (rotation axis Axw); and a plurality of blades 33 disposed on the hub surface 32. The turbine impeller 3 includes a plurality of flow paths 12 formed between two adjacent blades 33. When the area of ​​the throat 35A of the throat of at least one flow path 12 among the plurality of flow paths 12 is set as Aen, and the average area of ​​the throats 35 of the plurality of flow paths 12 is set as Aave, the relationship Aen / Aave>1.01 is satisfied.

[0099] In turbines, the closer the inflow angle of the exhaust gas at the leading edge of the turbine impeller is to the ideal inflow angle, the better the turbine's aerodynamic performance. However, if a boundary layer forms on the surface of the exhaust gas tongue during flow, generating a wake (low-speed region), the absolute velocity of the exhaust gas decreases, and the inflow angle of the exhaust gas at the leading edge of the turbine impeller deviates from the ideal inflow angle, potentially leading to a decrease in turbine efficiency.

[0100] According to the structure described in (1) above, the exhaust gas can easily flow in the enlarged flow path 12A at the throat. Therefore, even if a wake occurs as described above, the decrease in the absolute velocity of the exhaust gas can be suppressed, and the deviation of the inflow angle β of the exhaust gas at the leading edge 36 of the turbine impeller 3 from the ideal inflow angle can be suppressed. As a result, the decrease in the efficiency of the turbine 30 can be suppressed in the turbine 30 equipped with the turbine impeller 3 based on the structure described in (1) above.

[0101] (2) In several embodiments, according to the structure of (1) above, it is also possible to satisfy the relationship of Pen > Pave when the blade spacing between two adjacent blades 33 forming the throat expansion flow path 12A is set as Pen and the average value of the blade spacing P of multiple blades 33 is set as Pave.

[0102] According to the structure in (2) above, by making the blade spacing Pen of the two adjacent blades 33 forming the throat expansion flow path 12A larger than the average value Pave of the blade spacing P, it is relatively easy to make the area Aen of the throat 35A in the throat expansion flow path 12A larger than the average area Aave.

[0103] (3) In several embodiments, according to the structure of (1) or (2) above, it is also possible to satisfy the relationship that Ten < Tave when the blade thickness in the region forming the throat 35A of at least one of the two adjacent blades 33 forming the throat expansion flow path 12A is set as Ten, and the average value of the blade thickness T in the region forming the throat 35 of the plurality of blades 33 is set as Tave.

[0104] Based on the structure described in (3) above, it is relatively easy to make the area Aen of the throat 35A in the throat enlargement flow path 12A larger than the average area Aave described above.

[0105] (4) In several embodiments, according to any of the structures described in (1) to (3) above, the span distance between the hub surface 32 and the end point 34 of the blade 33 in the throat 35A of the throat-enlarged flow path 12A in the meridional plane of the turbine impeller 3 is set as Hen. The average value of the span distance between the hub surface 32 and the end point 34 of the blade 33 in the throat 35 of the plurality of flow paths 12 in the meridional plane of the turbine impeller 3 is set as Have. Furthermore, the relationship Hen > Have can also be satisfied.

[0106] In the structure described in (4) above, the area A of the throat 35 can be changed by altering the span distance H between the hub surface 32 and the end point 34 of the blade 33 in the throat 35. Therefore, by making the span distance Hen between the hub surface 32 and the end point 34 in the throat 35A of the throat-enlarged flow path 12A larger than the average span distance H Have, it is relatively easy to make the area Aen of the throat 35A in the throat-enlarged flow path 12A larger than the average area Aave.

[0107] (5) In several embodiments, according to any of the structures described in (1) to (4) above, at least one throat enlargement flow path 12A may also include multiple throat enlargement flow paths 12A.

[0108] The appropriate value for the number of throat enlargement flow paths 12A varies depending on, for example, the specifications of the turbocharger 1 and the specifications of the combined engine.

[0109] According to the structure of (5) above, instead of setting one, multiple throat enlargement flow paths 12A are set to effectively suppress the reduction in efficiency of turbine 30.

[0110] (6) In several embodiments, in the structure described in (5) above, the plurality of throat enlargement flow paths 12A may also be configured discretely.

[0111] Whether it is better to arrange the multiple throat enlargement flow paths 12A continuously along the circumference or discretely, for example, depends on the specifications of the turbocharger 1 and the combined engine.

[0112] According to the structure described above (6), it is effective when multiple throat enlargement flow paths 12A are discretely configured.

[0113] (7) In several embodiments, according to the structure of (5) above, multiple throat enlargement flow paths 12A can also be configured continuously.

[0114] As mentioned above, it is better to arrange the multiple throat enlargement flow paths 12A continuously along the circumference or discretely, for example, depending on the specifications of the turbocharger 1 and the combined engine.

[0115] According to the structure described above (7), it is effective when multiple throat enlargement flow paths 12A are continuously configured.

[0116] (8) The turbine 30 of at least one embodiment of the present disclosure has a turbine impeller 3 with any of the structures described in (1) to (7) above.

[0117] Based on the structure described in (8) above, the efficiency reduction of the turbine 30 can be suppressed.

[0118] (9) The turbocharger 1 of at least one embodiment of the present disclosure has a turbine 30 with the structure described in (8) above.

[0119] Based on the structure described above (9), the performance of the turbocharger 1 can be improved.

[0120] Explanation of reference numerals in the attached figures

[0121] 1. Turbocharger

[0122] 2. Rotating shaft (rotor shaft)

[0123] 3. Turbine impeller

[0124] 5. Housing (Turbine Housing)

[0125] 12 flow path

[0126] 12A Throat Enlarged Flow Path

[0127] 30 Turbo

[0128] 31-inch wheels

[0129] 32 wheel hub surface

[0130] 33, 33A Blades (Moving Blades)

[0131] 34 End

[0132] 35, 35A Throat

[0133] 36. Prelude

[0134] 37. Trailing edge

Claims

1. A turbine comprising a turbine impeller and a housing, the turbine impeller being connected to and rotating about a rotating shaft, the housing rotatably housing the turbine impeller, the turbine being characterized in that... The housing comprises: The vortex section has an internal vortex flow path; The tongue separates the vortex flow path from the flow path that is radially outer than the vortex flow path; The turbine impeller has: A hub having a hub surface that is inclined relative to the axis in a cross section along the axis; Multiple blades are disposed on the hub surface; The turbine impeller includes multiple flow paths formed between two adjacent blades. Let Aen be the area of ​​the throat of the expanded flow path, which is the throat of at least one of the plurality of flow paths. When the average area of ​​the throat of the plurality of flow paths is set to Aave, The relationship Aen / Aave > 1.01 is satisfied.

2. The turbine as claimed in claim 1, wherein, The blade spacing between the two adjacent blades forming the throat expansion flow path is set to Pen. When the average distance between the multiple blades is set as Pave, The relationship Pen > Pave is satisfied.

3. The turbine as claimed in claim 1, wherein, The blade thickness in the region forming the throat of at least one of the two adjacent blades that form the throat expansion flow path is defined as Ten. If the average thickness of the blades in the region forming the throat of the plurality of blades is set as Tave. The relationship Ten < Tave is satisfied.

4. The turbine as claimed in claim 1, wherein, In the meridional plane of the turbine impeller, The span distance between the hub surface and the tip of the blade in the throat, which expands the flow path, is defined as Hen. When the average value of the span distance between the hub surface and the tip of the blade in the throat of the plurality of flow paths is set as Have, The relationship Hen > Have is satisfied.

5. The turbine as claimed in any one of claims 1 to 4, wherein, The at least one throat enlargement flow path includes multiple throat enlargement flow paths.

6. The turbine as claimed in claim 5, wherein, The multiple throat-enlarged flow paths are discretely configured.

7. The turbine as claimed in claim 5, wherein, The multiple throat-enlarged flow paths are configured continuously.

8. A turbocharger, characterized in that, It has a turbine as described in any one of claims 1 to 7.

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