Turbochargers and turbochargers

Abstract

This turbine T is equipped with: a shaft; a turbine wheel attached to one side of the shaft; a housing section for housing the turbine wheel; a first turbine scroll channel 31 which is connected to the housing section and is wound on the outside of the turbine wheel in the radial direction; a second turbine scroll channel 33 which is connected to the housing section, is wound on the outside of the turbine wheel in the radial direction, and is positioned on the one side of the first turbine scroll channel; a first tongue part 43 which is provided at a location facing the downstream end of the first turbine scroll channel 31, and is angled one way in the circumferential direction of the turbine wheel toward the one side; and a second tongue part 51 which is provided at a location facing the downstream end of the second turbine scroll channel 33, and is angled the other way in the circumferential direction of the turbine wheel toward said one side.

Description

[Technical field]

[0001] This disclosure relates to a turbine and a turbocharger. This application claims the benefit of priority from Japanese Patent Application No. 2021-182419 filed on November 9, 2021, the contents of which are incorporated herein by reference. [Background technology]

[0002] For example, as disclosed in Patent Document 1, a turbine provided in a turbocharger or the like has two turbine scroll passages wound radially outwardly around a turbine wheel and aligned in the axial direction of the turbine wheel. A tongue is provided at a position facing the downstream end of each turbine scroll passage. Such a turbine is also called a twin-scroll turbine. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2006-348894 A Summary of the Invention [Problem to be solved by the invention]

[0004] In a turbine having a tongue portion, such as a twin scroll turbine, when the blades of the turbine wheel pass near the tongue portion, the flow passage area formed by the blades and the tongue portion momentarily narrows, causing a contraction of the gas. This causes the force acting on the blades to fluctuate greatly, causing blade vibration. It is desirable to reduce the blade vibration of such a turbine wheel.

[0005] An object of the present disclosure is to provide a turbine and a turbocharger capable of reducing blade vibration of a turbine wheel. [Means for solving the problem]

[0006] In order to solve the above problems, a turbine disclosed herein includes a shaft, a turbine wheel attached to one side of the shaft, a housing section that houses the turbine wheel, a first turbine scroll passage that is wound radially outwardly around the turbine wheel and communicates with the housing section, a second turbine scroll passage that is wound radially outwardly around the turbine wheel and communicates with the housing section and is lined up on one side of the first turbine scroll passage, a first tongue portion that is provided at a position facing a downstream end of the first turbine scroll passage and inclined toward one circumferential side of the turbine wheel as it progresses to that side, and a second tongue portion that is provided at a position facing the downstream end of the second turbine scroll passage and inclined toward the other circumferential side of the turbine wheel as it progresses to that side. When viewed in the radial direction of the turbine wheel, the first tongue portion and the second tongue portion extend linearly. .

[0007] The first tongue portion may be inclined in a rotation direction of the turbine wheel as it progresses to one side, and the second tongue portion may be inclined in a direction opposite to the rotation direction as it progresses to one side.

[0008] The first tongue portion may be inclined in a direction opposite to a rotation direction of the turbine wheel as it progresses to one side, and the second tongue portion may be inclined in the rotation direction as it progresses to one side.

[0009] The inclination angle of the first and second tongue portions with respect to the axial direction of the turbine wheel when viewed in the radial direction of the turbine wheel may be equal to or smaller than an angle obtained by dividing 360° by the number of blades of the turbine wheel.

[0010] In order to solve the above problem, a turbocharger according to the present disclosure includes the above turbine. Effect of the Invention

[0011] According to the present disclosure, it is possible to reduce the vibration of the turbine wheel blades. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic cross-sectional view showing a turbocharger according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a cross-sectional view taken along line AA of FIG. [Diagram 3] FIG. 3 is a cross-sectional view taken along line BB of FIG. [Figure 4] FIG. 4 is a cross-sectional view taken along line CC of FIGS. [Diagram 5] FIG. 5 is a cross-sectional view taken along line DD of FIG. [Figure 6] FIG. 6 is a DD cross-sectional view of a turbine according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of the present disclosure will be described with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values ​​shown in the embodiments are merely examples for ease of understanding, and do not limit the present disclosure unless otherwise specified. In this specification and drawings, elements having substantially the same functions and configurations are given the same reference numerals to avoid repeated explanations, and elements not directly related to the present disclosure are not illustrated.

[0014] Fig. 1 is a schematic cross-sectional view showing a turbocharger TC according to an embodiment of the present disclosure. In the following description, the direction of arrow L shown in Fig. 1 is the left side of the turbocharger TC. The direction of arrow R shown in Fig. 1 is the right side of the turbocharger TC. As shown in Fig. 1, the turbocharger TC includes a turbocharger body 1. The turbocharger body 1 includes a bearing housing 3, a turbine housing 5, and a compressor housing 7.

[0015] The turbine housing 5 is connected to the left side of the bearing housing 3 by a fastening mechanism 9. The fastening mechanism 9 is, for example, a G-coupling. The compressor housing 7 is connected to the right side of the bearing housing 3 by a fastening bolt 11. The turbocharger TC includes a turbine T and a centrifugal compressor C. The turbine T includes a bearing housing 3 and a turbine housing 5. The turbine T is a twin-scroll type turbine. The centrifugal compressor C includes a bearing housing 3 and a compressor housing 7.

[0016] A bearing hole 3a is formed in the bearing housing 3. The bearing hole 3a penetrates the turbocharger TC in the left-right direction. A bearing 13 is provided in the bearing hole 3a. In FIG. 1, a full-floating bearing is shown as an example of the bearing 13. However, the bearing 13 may be another bearing such as a semi-floating bearing or a rolling bearing. The bearing 13 rotatably supports the shaft 15. A turbine wheel 17 is provided at the left end of the shaft 15. In this manner, the turbine wheel 17 is attached to the left side, which is one side of the shaft 15. The turbine wheel 17 is rotatably accommodated in the turbine housing 5. A compressor wheel 19 is provided at the right end of the shaft 15. The compressor wheel 19 is rotatably accommodated in the compressor housing 7.

[0017] Hereinafter, the axial direction, radial direction, and circumferential direction of the turbocharger TC will also be simply referred to as the axial direction, radial direction, and circumferential direction, respectively. The axial direction of the turbocharger TC coincides with the axial direction of the shaft 15, the axial direction of the turbine wheel 17, and the axial direction of the compressor wheel 19. The radial direction of the turbocharger TC coincides with the radial direction of the shaft 15, the radial direction of the turbine wheel 17, and the radial direction of the compressor wheel 19. The circumferential direction of the turbocharger TC coincides with the circumferential direction of the shaft 15, the circumferential direction of the turbine wheel 17, and the circumferential direction of the compressor wheel 19.

[0018] An intake port 21 is formed in the compressor housing 7. The intake port 21 opens to the right side of the turbocharger TC. The intake port 21 is connected to an air cleaner (not shown). A diffuser passage 23 is formed by the opposing surfaces of the bearing housing 3 and the compressor housing 7. The diffuser passage 23 pressurizes the air. The diffuser passage 23 is formed in an annular shape. The diffuser passage 23 communicates with the intake port 21 via the compressor impeller 19 on the radially inner side.

[0019] Further, a compressor scroll passage 25 is formed in the compressor housing 7. The compressor scroll passage 25 is formed in an annular shape. The compressor scroll passage 25 is located, for example, radially outward of the diffuser passage 23. The compressor scroll passage 25 communicates with an intake port of an engine (not shown) and the diffuser passage 23. When the compressor impeller 19 rotates, air is taken into the compressor housing 7 from the intake port 21. The taken-in air is pressurized and accelerated in the process of flowing between the blades of the compressor impeller 19. The pressurized and accelerated air is pressurized in the diffuser passage 23 and the compressor scroll passage 25. The pressurized air is led to the intake port of the engine.

[0020] The turbine housing 5 is formed with an exhaust passage 27, an accommodation section 29, a first turbine scroll passage 31, and a second turbine scroll passage 33. The exhaust passage 27 opens to the left side of the turbocharger TC. The exhaust passage 27 is connected to an exhaust gas purification device (not shown). The exhaust passage 27 communicates with the accommodation section 29. The exhaust passage 27 is continuous with the accommodation section 29 in the axial direction. The accommodation section 29 accommodates the turbine impeller 17. The first turbine scroll passage 31 and the second turbine scroll passage 33 are provided radially outside the accommodation section 29.

[0021] The first turbine scroll passage 31 and the second turbine scroll passage 33 are wound around the turbine wheel 17 radially outward. The first turbine scroll passage 31 and the second turbine scroll passage 33 communicate with the accommodation section 29. The second turbine scroll passage 33 is arranged on the left side of the first turbine scroll passage 31 in the axial direction (i.e., on one side of the shaft 15 to which the turbine wheel 17 is attached). A partition plate 35 is formed between the first turbine scroll passage 31 and the second turbine scroll passage 33. The partition plate 35 divides the first turbine scroll passage 31 and the second turbine scroll passage 33 in the axial direction. The first turbine scroll passage 31 and the second turbine scroll passage 33 communicate with an exhaust manifold of an engine (not shown). Exhaust gas discharged from an exhaust manifold of an engine (not shown) is sent to the accommodation section 29 via the first turbine scroll passage 31 and the second turbine scroll passage 33, and then led to the exhaust passage 27. The exhaust gas guided to the exhaust passage 27 rotates the turbine wheel 17 during the flow process.

[0022] The rotational force of the turbine wheel 17 is transmitted to the compressor wheel 19 via the shaft 15. When the compressor wheel 19 rotates, the air is pressurized as described above. In this manner, the air is guided to the intake port of the engine.

[0023] Fig. 2 is a cross-sectional view taken along line AA in Fig. 1. The cross-section AA is perpendicular to the axial direction of the shaft 15 and passes through the first turbine scroll passage 31. In Fig. 2, only the outer periphery of the turbine wheel 17 is shown as a circle.

[0024] 2, a first exhaust introduction port 37 is formed in the turbine housing 5. The first exhaust introduction port 37 opens to the outside of the turbine housing 5. Exhaust gas discharged from an exhaust manifold of an engine (not shown) is introduced into the first exhaust introduction port 37.

[0025] A first exhaust introduction passage 39 is formed between the first exhaust introduction port 37 and the first turbine scroll passage 31. The first exhaust introduction passage 39 connects the first exhaust introduction port 37 and the first turbine scroll passage 31. The first exhaust introduction passage 39 is formed, for example, in a straight line. The first exhaust introduction passage 39 guides the exhaust gas introduced from the first exhaust introduction port 37 to the first turbine scroll passage 31.

[0026] The first turbine scroll passage 31 communicates with the accommodation section 29 via a first communication part 41. The first communication part 41 is formed in an annular shape around the entire circumference of the accommodation section 29. The first turbine scroll passage 31 guides the exhaust gas introduced from the first exhaust introduction passage 39 to the accommodation section 29 via the first communication part 41. The first turbine scroll passage 31 is wound so as to approach the turbine wheel 17 as it advances in the rotation direction RD of the turbine wheel 17. The radial width of the first turbine scroll passage 31 decreases from the upstream side to the downstream side.

[0027] A first tongue portion 43 is provided at a position facing the downstream end of the first turbine scroll passage 31. The first tongue portion 43 separates the first turbine scroll passage 31 from a downstream portion and an upstream portion.

[0028] Fig. 3 is a BB cross-sectional view of Fig. 1. The BB cross-section is a cross section perpendicular to the axial direction of the shaft 15 and passing through the second turbine scroll passage 33. In Fig. 3, similar to Fig. 2, only the outer periphery of the turbine wheel 17 is shown as a circle.

[0029] As shown in Fig. 3, the turbine housing 5 is formed with a second exhaust inlet 45. The second exhaust inlet 45 opens to the outside of the turbine housing 5. The second exhaust inlet 45 is aligned on the left side in the axial direction with respect to the first exhaust inlet 37 (i.e., on one side of the shaft 15 to which the turbine impeller 17 is attached). The first exhaust inlet 37 and the second exhaust inlet 45 are partitioned in the axial direction by the partition plate 35. Exhaust gas discharged from an exhaust manifold of an engine (not shown) is introduced into the second exhaust inlet 45.

[0030] A second exhaust introduction passage 47 is formed between the second exhaust introduction port 45 and the second turbine scroll passage 33. The second exhaust introduction passage 47 connects the second exhaust introduction port 45 and the second turbine scroll passage 33. The second exhaust introduction passage 47 is formed, for example, in a straight line. The second exhaust introduction passage 47 is arranged on the left side of the first exhaust introduction passage 39 in the axial direction (i.e., on one side of the shaft 15 to which the turbine impeller 17 is attached). The first exhaust introduction passage 39 and the second exhaust introduction passage 47 are partitioned in the axial direction by the partition plate 35. The second exhaust introduction passage 47 guides the exhaust gas introduced from the second exhaust introduction port 45 to the second turbine scroll passage 33.

[0031] The second turbine scroll passage 33 communicates with the accommodation section 29 via the second communication part 49. The second communication part 49 is formed in an annular shape around the entire circumference of the accommodation section 29. The second communication part 49 is arranged on the left side in the axial direction with respect to the first communication part 41 (i.e., one side of the shaft 15 to which the turbine wheel 17 is attached). The first communication part 41 and the second communication part 49 are partitioned in the axial direction by the partition plate 35. The second turbine scroll passage 33 guides the exhaust gas introduced from the second exhaust introduction passage 47 to the accommodation section 29 via the second communication part 49. The second turbine scroll passage 33 is wound so as to approach the turbine wheel 17 as it advances in the rotation direction RD of the turbine wheel 17. The radial width of the second turbine scroll passage 33 decreases from the upstream side to the downstream side.

[0032] A second tongue portion 51 is provided at a position facing the downstream end of the second turbine scroll passage 33. The second tongue portion 51 separates a downstream portion from an upstream portion of the second turbine scroll passage 33. The circumferential position of the first tongue portion 43 and the circumferential position of the second tongue portion 51 coincide with each other.

[0033] Fig. 4 is a cross-sectional view taken along line CC of Fig. 2 and Fig. 3. The CC cross section passes through the first tongue portion 43 and the second tongue portion 51 and includes the rotation axis of the turbine wheel 17.

[0034] As shown in FIG. 4, the turbine wheel 17 has a plurality of blade bodies 17a. The blade bodies 17a are provided at equal intervals in the circumferential direction. Each blade body 17a is formed extending radially outward from the outer circumferential surface of a hub extending on the rotation axis of the turbine wheel 17. In the example of FIG. 4, the leading edge LE of the blade body 17a extends parallel to the rotation axis of the turbine wheel 17. However, the leading edge LE may be inclined radially outward as it advances to the left side in the axial direction (i.e., one side of the shaft 15 to which the turbine wheel 17 is attached). The leading edge LE is a portion of the outer circumferential edge of the blade body 17a that faces the first turbine scroll passage 31 and the second turbine scroll passage 33. Exhaust gas flows from the first turbine scroll passage 31 and the second turbine scroll passage 33 through the vicinity of the leading edge LE into the accommodation section 29.

[0035] The first tongue portion 43 and the second tongue portion 51 are disposed radially outward of the leading edge LE of the blade body 17a of the turbine wheel 17. In the example of Fig. 4, the portions of the first tongue portion 43 and the second tongue portion 51 facing the turbine wheel 17 extend parallel to the rotation axis of the turbine wheel 17. In other words, the portions of the first tongue portion 43 and the second tongue portion 51 facing the turbine wheel 17 extend parallel to the leading edge LE. Hereinafter, when there is no particular distinction between the first tongue portion 43 and the second tongue portion 51, they will simply be referred to as tongue portions.

[0036] In the turbine T, when the blade body 17a of the turbine impeller 17 passes near the tongue, the flow passage area formed by the blade body 17a and the tongue is instantaneously narrowed, causing a contraction of the gas. This causes the force acting on the blade body 17a to fluctuate greatly, causing blade vibration. In this embodiment, the shape of the tongue is designed to reduce the blade vibration of the turbine impeller 17.

[0037] Fig. 5 is a DD cross-sectional view of Fig. 4. The DD cross-section is a cross-section passing through the first tongue portion 43 and the second tongue portion 51 along the circumferential direction of the turbine wheel 17. The DD cross-section is a cross-sectional view of the first tongue portion 43 and the second tongue portion 51 viewed in the radial direction from the turbine wheel 17 side. In Fig. 5, the DD cross-sectional view of Fig. 4 is shown with the direction of arrow L as the upward direction and the direction of arrow R as the downward direction.

[0038] 5, in turbine T, the first tongue portion 43 inclines in the rotation direction RD of the turbine wheel 17 as it progresses in the direction of arrow L. That is, the first tongue portion 43 inclines in the rotation direction RD as it progresses toward one side of the shaft 15 where the turbine wheel 17 is attached. The second tongue portion 51 inclines in the opposite direction to the rotation direction RD of the turbine wheel 17 as it progresses in the direction of arrow L. That is, the second tongue portion 51 inclines in the opposite direction to the rotation direction RD as it progresses toward one side of the shaft 15 where the turbine wheel 17 is attached.

[0039] As described above, in the turbine T, the first tongue portion 43 inclines toward one side in the circumferential direction of the turbine wheel 17 as it advances toward one side of the shaft 15 where the turbine wheel 17 is attached, and the second tongue portion 51 inclines toward the other side in the circumferential direction of the turbine wheel 17 as it advances toward the one side. Therefore, when each tongue portion is viewed radially from the turbine wheel 17 side, each tongue portion is inclined in the circumferential direction with respect to the axial direction of the turbine wheel 17. As a result, when the blade body 17a of the turbine wheel 17 passes near the tongue portion, a part of each tongue portion sequentially faces the blade body 17a.

[0040] Regarding the first tongue portion 43, first, the portion of the first tongue portion 43 on the arrow R direction side faces the blade body 17a. Then, the portion of the first tongue portion 43 facing the blade body 17a transitions to the arrow L direction side. Regarding the second tongue portion 51, first, the portion of the second tongue portion 51 on the arrow L direction side faces the blade body 17a. Then, the portion of the second tongue portion 51 facing the blade body 17a transitions to the arrow R direction side. Therefore, for each tongue portion, the blade body 17a of the turbine impeller 17 is prevented from facing the entire tongue portion at the same time. Therefore, when the blade body 17a of the turbine impeller 17 passes near the tongue portion, the degree to which the flow path area formed by the blade body 17a and the tongue portion is momentarily narrowed is suppressed, and the occurrence of contraction of the gas is suppressed. Therefore, the instantaneous fluctuation of the force acting on the blade body 17a is suppressed, and the blade vibration is reduced.

[0041] Furthermore, in the turbine T, when each tongue is viewed in the radial direction from the turbine wheel 17 side, the direction in which the first tongue 43 is inclined with respect to the axial direction of the turbine wheel 17 is opposite to the direction in which the second tongue 51 is inclined with respect to the axial direction of the turbine wheel 17. As a result, the flow of gas flowing from the vicinity of the first tongue 43 into the accommodation section 29 of the turbine wheel 17 and the flow of gas flowing from the vicinity of the second tongue 51 into the accommodation section 29 of the turbine wheel 17 are plane-symmetrical with respect to the central plane of the partition plate 35. The central plane of the partition plate 35 is a plane that passes through the center in the thickness direction of the partition plate 35 and is perpendicular to the axial direction. Therefore, the axial component of the flow of gas flowing from the vicinity of the first tongue 43 into the accommodation section 29 of the turbine wheel 17 and the axial component of the flow of gas flowing from the vicinity of the second tongue 51 into the accommodation section 29 of the turbine wheel 17 cancel each other out. This suppresses the generation of vortex flows in the vicinity of the blade body 17a, and more effectively suppresses instantaneous fluctuations in the force acting on the blade body 17a, thereby more effectively reducing blade vibration.

[0042] The first tongue portion 43 and the second tongue portion 51 do not necessarily have to be plane-symmetrical with respect to the central plane of the partition plate 35. Even if the first tongue portion 43 and the second tongue portion 51 are not plane-symmetrical with respect to the central plane of the partition plate 35, the axial component of the gas flow flowing from the vicinity of the first tongue portion 43 into the housing portion 29 of the turbine wheel 17 and the axial component of the gas flow flowing from the vicinity of the second tongue portion 51 into the housing portion 29 of the turbine wheel 17 at least partially cancel each other out, thereby reducing blade vibration.

[0043] In particular, in the turbine T, the first tongue portion 43 is inclined in the rotation direction RD as it advances toward one side of the shaft 15 where the turbine wheel 17 is attached, and the second tongue portion 51 is inclined in the opposite direction to the rotation direction RD as it advances toward the one side. As a result, gas flowing from the vicinity of the first tongue portion 43 into the housing portion 29 of the turbine wheel 17 is guided by the first tongue portion 43 to the left side in the axial direction. On the other hand, gas flowing from the vicinity of the second tongue portion 51 into the housing portion 29 of the turbine wheel 17 is guided by the second tongue portion 51 to the opposite side from the left side in the axial direction. Therefore, gas flowing from the vicinity of each tongue portion into the housing portion 29 of the turbine wheel 17 flows toward the center side in the axial direction of the blade body 17a. This improves aerodynamic performance.

[0044] The following describes the inclination angles of the first tongue portion 43 and the second tongue portion 51 with respect to the axial direction when viewed in the radial direction of the turbine wheel 17. Fig. 5 shows the inclination angle θ1 of the first tongue portion 43 with respect to the axial direction when viewed in the radial direction of the turbine wheel 17, and the inclination angle θ2 of the second tongue portion 51 with respect to the axial direction when viewed in the radial direction of the turbine wheel 17.

[0045] The inclination angles θ1 and θ2 are approximately equal. The larger the inclination angles θ1 and θ2, the more effectively the flow passage area formed by the blade body 17a and the tongue portion is momentarily narrowed when the blade body 17a of the turbine impeller 17 passes near the tongue portion, and the more effectively the occurrence of gas contraction is suppressed. Therefore, the instantaneous fluctuation of the force acting on the blade body 17a is more effectively suppressed, and the blade vibration is more effectively reduced. On the other hand, if the inclination angles θ1 and θ2 are excessively large, the flow field in the housing portion 29 of the turbine impeller 17 may deviate significantly from the expected state, and the aerodynamic performance may be degraded.

[0046] From the viewpoint of suppressing the deterioration of aerodynamic performance, it is preferable that the inclination angles θ1 and θ2 are equal to or smaller than an angle obtained by dividing 360° by the number of blades 17a of the turbine impeller 17. The more the number of blades 17a, the shorter the time difference between the timing when the adjacent blades 17a face the tongue portion. By setting the inclination angles θ1 and θ2 as described above, the more the number of blades 17a, the smaller the inclination angles θ1 and θ2 can be. This prevents the time taken for each blade 17a to pass through the tongue portion from being excessively long relative to the above-mentioned time difference. Therefore, the flow field in the housing portion 29 of the turbine impeller 17 is prevented from deviating significantly from the expected state, and the deterioration of aerodynamic performance is suppressed.

[0047] However, the inclination angles θ1 and θ2 do not have to be equal to or less than the angle obtained by dividing 360° by the number of blades 17a of the turbine wheel 17. In addition, the inclination angles θ1 and θ2 may be different from each other.

[0048] In the above, an example has been described in which, when viewed in the circumferential direction of the turbine wheel 17, the tongue portions are not inclined in the radial direction with respect to the axial direction of the turbine wheel 17. However, when viewed in the circumferential direction of the turbine wheel 17, at least one of the first tongue portion 43 and the second tongue portion 51 may be inclined in the radial direction with respect to the axial direction of the turbine wheel 17.

[0049] 6 is a DD cross-sectional view of a turbine T1 according to a modified example. The turbine T1 is different from the turbine T described above in that the inclination directions of the first tongue portion 43 and the second tongue portion 51 are different.

[0050] 6, in turbine T1, the first tongue portion 43 inclines in the opposite direction to the rotation direction RD of the turbine wheel 17 as it progresses in the direction of arrow L. That is, the first tongue portion 43 inclines in the opposite direction to the rotation direction RD as it progresses toward one side of the shaft 15 where the turbine wheel 17 is attached. The second tongue portion 51 inclines in the rotation direction RD of the turbine wheel 17 as it progresses in the direction of arrow L. That is, the second tongue portion 51 inclines in the rotation direction RD as it progresses toward one side of the shaft 15 where the turbine wheel 17 is attached.

[0051] As described above, in turbine T1, similarly to the above-described turbine T, the first tongue portion 43 inclines toward one side in the circumferential direction of the turbine wheel 17 as it advances toward one side of the shaft 15 where the turbine wheel 17 is attached, and the second tongue portion 51 inclines toward the other side in the circumferential direction of the turbine wheel 17 as it advances toward the above-described one side. Therefore, similarly to the above-described turbine T, an effect of reducing blade vibration is achieved.

[0052] In particular, in the turbine T1, the first tongue portion 43 is inclined in the direction opposite to the rotation direction RD as it advances toward one side of the shaft 15 where the turbine impeller 17 is attached, and the second tongue portion 51 is inclined in the rotation direction RD as it advances toward the one side. As a result, in the portions of the first turbine scroll passage 31 and the second turbine scroll passage 33 adjacent to the tongue portions on the upstream side (portions to the left of the first tongue portion 43 and the second tongue portion 51 in FIG. 6), the angles formed between the tongue portions and the inner surfaces of the turbine scroll passages facing the partition plate 35 are obtuse angles. Therefore, on the upstream side of each turbine scroll passage where the gas closer to the engine exhaust and more energetic hits, cracks are suppressed from occurring in the boundary portions between the tongue portions and each turbine scroll passage.

[0053] In the turbine T1, similarly to the turbine T1, the inclination angles θ1 and θ2 may be equal to or less than an angle obtained by dividing 360° by the number of blades 17a of the turbine wheel 17, or may not be equal to or less than this angle. The inclination angles θ1 and θ2 may be substantially equal to or different from each other. When viewed in the circumferential direction of the turbine wheel 17, each tongue portion may not be inclined radially with respect to the axial direction of the turbine wheel 17, and at least one of the first tongue portion 43 and the second tongue portion 51 may be inclined radially with respect to the axial direction of the turbine wheel 17.

[0054] Although the embodiments of the present disclosure have been described above with reference to the accompanying drawings, it goes without saying that the present disclosure is not limited to such embodiments. It is clear that a person skilled in the art can think of various modified or altered examples within the scope of the claims, and it is understood that these also naturally belong to the technical scope of the present disclosure.

[0055] Although an example in which the turbine T is mounted on the turbocharger TC has been described above, the turbine T may be mounted on a device other than the turbocharger TC, such as a generator.

[0056] This disclosure can reduce the blade vibration of turbine wheels, thereby contributing, for example, to Sustainable Development Goal (SDG) Goal 7 "Ensure access to affordable, reliable, sustainable and modern energy" and Goal 9 "Build resilient infrastructure, promote sustainable industrialization and foster innovation." [Explanation of symbols]

[0057] 15: shaft 17: turbine impeller 17a: impeller body 29: housing 31: first turbine scroll passage 33: second turbine scroll passage 43: first tongue portion 51: second tongue portion RD: direction of rotation T: turbine T1: turbine TC: turbocharger θ1: inclination angle θ2 Tilt angle

Claims

1. A shaft, a turbine wheel attached to one side of the shaft; a housing portion that houses the turbine wheel; a first turbine scroll passage wound radially outwardly around the turbine wheel and communicating with the housing; a second turbine scroll passage that is wound radially outwardly around the turbine wheel, that is in communication with the accommodation portion, and that is aligned on the one side of the first turbine scroll passage; a first tongue portion provided at a position facing a downstream end of the first turbine scroll passage and inclined toward one side in a circumferential direction of the turbine wheel as it advances toward the one side; a second tongue portion provided at a position facing a downstream end of the second turbine scroll passage and inclined toward the other side in the circumferential direction of the turbine wheel as the second tongue portion advances toward the one side; Equipped with When viewed in a radial direction of the turbine wheel, the first tongue portion and the second tongue portion extend linearly. Turbine.

2. the first tongue portion is inclined in a rotation direction of the turbine wheel as it progresses to the one side, the second tongue portion inclines in a direction opposite to the rotation direction as it advances to the one side, The turbine of claim 1 .

3. the first tongue portion is inclined in a direction opposite to a rotation direction of the turbine wheel as it advances to the one side, The second tongue portion is inclined in the rotation direction as it progresses to the one side. The turbine of claim 1 .

4. an inclination angle of the first tongue portion and the second tongue portion with respect to an axial direction of the turbine wheel when viewed in a radial direction of the turbine wheel is equal to or smaller than an angle obtained by dividing 360° by the number of blade bodies of the turbine wheel. The turbine of claim 1 .

5. an inclination angle of the first tongue portion and the second tongue portion with respect to an axial direction of the turbine wheel when viewed in a radial direction of the turbine wheel is equal to or smaller than an angle obtained by dividing 360° by the number of blade bodies of the turbine wheel. The turbine of claim 2 .

6. an inclination angle of the first tongue portion and the second tongue portion with respect to an axial direction of the turbine wheel when viewed in a radial direction of the turbine wheel is equal to or smaller than an angle obtained by dividing 360° by the number of blade bodies of the turbine wheel. The turbine of claim 3.

7. A turbine comprising: Supercharger.

8. A turbine comprising: Supercharger.

9. A turbine comprising: Supercharger.

10. A turbine comprising: Supercharger.

11. A turbine comprising: Supercharger.

12. A turbine comprising: Supercharger.

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