JP2023148347A - Turbine and supercharger - Google Patents

Abstract

To maintain a circumferential length of a surface formed by a machined surface of a tongue part at an appropriate design length.SOLUTION: A turbine comprises: a turbine housing in which turbine scroll passages 37a, 37b are formed around a turbine impeller 17; a tongue part 43b formed in the turbine housing, and partitioning an inner diameter side surface of the turbine scroll flow path 37a and an outer diameter side surface of the turbine scroll flow path 37b; an upstream side end surface 51 that is formed on an upstream side of the tongue part 43b in a rotation direction RD of the turbine impeller 17, and has a surface on an outer diameter side of the turbine scroll flow path 37b in which a flow path cross-sectional area of the turbine scroll flow path 37b linearly decreases; and a downstream side end surface 53 that is formed on a downstream side of the tongue part 43b in the rotational direction RD of the turbine impeller 17, and has a surface parallel to the upstream side end surface 51.SELECTED DRAWING: Figure 4

Description

TECHNICAL FIELD This disclosure relates to turbines and superchargers.

Patent Document 1 discloses a housing that is cast using a metal mold and in which a scroll passage is formed by a core placed inside the mold. A tongue portion is formed inside the housing after casting to partition the inner diameter side surface and the outer diameter side surface of the scroll flow path.

Japanese Patent Application Publication No. 7-208397

A turbine housing is an example of a housing that is cast using a metal mold and has a scroll passage formed by a core. In some turbine housings, after the turbine housing is cast, depending on the application, the tongue portion is machined to form a surface of the tongue portion that faces the turbine wheel in the radial direction.

However, when the core moves within the mold during casting of the turbine housing, the tongue portion shifts relative to the machined surface as the core moves. If the tongue portion deviates from the machined surface, it becomes difficult to maintain the circumferential length of the surface of the tongue portion formed by the machined surface at an appropriate design length.

The present disclosure provides a turbine and a supercharger that can maintain the circumferential length of a surface formed by a machined surface of a tongue portion to an appropriate design length.

In order to solve the above problems, the turbine of the present disclosure includes a turbine housing in which a scroll passage is formed around a turbine impeller, and a scroll passage formed in the turbine housing, and a and a surface on the outer diameter side of the scroll flow path, which is formed on the upstream side of the tongue in the rotation direction of the turbine impeller, and where the cross-sectional area of the scroll flow path linearly decreases. It includes an upstream end surface, and a downstream end surface that is formed on the downstream side of the tongue in the rotational direction of the turbine wheel and has a surface parallel to the upstream end surface.

The turbine housing has a housing portion in which the turbine wheel is disposed, and the scroll passage has a first scroll passage communicating with the housing portion and a position different from the first scroll passage in the rotational direction of the turbine wheel. and a second scroll flow path communicating with the accommodation portion, and the tongue has an upstream end face and a downstream end face, and the tongue has an inner diameter side surface of the first scroll flow path and a second scroll flow path. The first tongue portion has an upstream end face and a downstream end face, and has an inner diameter side surface of the second scroll flow path and an outer diameter side surface of the first scroll flow path. A second tongue section may be included.

The tongue portion may be configured as a separate member from the turbine housing.

In order to solve the above problems, a supercharger of the present disclosure includes the above turbine.

According to the present disclosure, the circumferential length of the surface of the tongue portion formed by the machined surface can be maintained at an appropriate design length.

FIG. 1 is a schematic cross-sectional view showing a supercharger according to an embodiment of the present disclosure. FIG. 2 is a sectional view taken along line AA in FIG. FIG. 3 is a partially enlarged view of the broken line portion shown in FIG. 2. FIG. FIG. 4 is a diagram for explaining the state of the tongue portion shown in FIG. 3 during machining. FIG. 5 is a diagram for explaining the state during machining when the tongue shown in FIG. 4 is misaligned. FIG. 6 is a diagram for explaining the relationship between the flow passage cross-sectional area of the turbine scroll passage and the circumferential position of the scroll outlet. FIG. 7 is a diagram for explaining the configuration of a tongue portion according to a modified example of the present disclosure.

An embodiment of the present disclosure will be described below with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiments are merely examples for easy 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 designated by the same reference numerals to omit redundant explanation, and elements not directly related to the present disclosure are omitted from illustration. do.

FIG. 1 is a schematic cross-sectional view showing a supercharger TC according to an embodiment of the present disclosure. In the following, the direction of arrow L shown in FIG. 1 will be explained as being on the left side of the supercharger TC. The direction of arrow R shown in FIG. 1 will be explained as being on the right side of the supercharger TC. Hereinafter, as an example of the supercharger TC, the configuration of the supercharger TC shown in FIG. 1 will be described in detail. As shown in FIG. 1, the supercharger TC includes a supercharger main body 1. The supercharger main body 1 includes a bearing housing 3, a turbine housing 5, and a compressor housing 7. The turbine housing 5 is connected to the left side of the bearing housing 3 by a fastening bolt 9. The compressor housing 7 is connected to the right side of the bearing housing 3 by a fastening bolt 11. The supercharger 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 so-called double scroll type turbine. Centrifugal compressor C includes a bearing housing 3 and a compressor housing 7.

A bearing hole 3a is formed in the bearing housing 3. The bearing hole 3a passes through the supercharger TC in the left-right direction. A semi-floating bearing 13 is arranged in the bearing hole 3a. The semi-floating bearing 13 rotatably supports the shaft 15. A turbine wheel 17 is provided at the left end of the shaft 15 . The turbine wheel 17 is rotatably housed in the turbine housing 5. A compressor impeller 19 is provided at the right end of the shaft 15. The compressor impeller 19 is rotatably housed in the compressor housing 7. Hereinafter, the axial direction, radial direction, and circumferential direction of the shaft 15 will be simply referred to as the axial direction, radial direction, and circumferential direction, respectively.

An intake port 21 is formed in the compressor housing 7 . The intake port 21 opens on the right side of the supercharger TC. The intake port 21 is connected to an air cleaner (not shown). A diffuser flow path 23 is formed by opposing surfaces of the bearing housing 3 and the compressor housing 7. The diffuser flow path 23 increases the pressure of the air. The diffuser flow path 23 is formed in an annular shape. The diffuser flow path 23 communicates with the intake port 21 via the compressor impeller 19 on the inside in the radial direction.

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 flow path 25 is located, for example, on the outer side in the radial direction than the diffuser flow path 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 sucked into the compressor housing 7 through the intake port 21. The intake 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 flow path 23 and the compressor scroll flow path 25. The pressurized air is guided to the engine intake.

The turbine housing 5 is formed with an exhaust flow path 27, a housing portion 29, and an exhaust flow path 31. The discharge flow path 27 opens on the left side of the supercharger TC. The exhaust flow path 27 is connected to an exhaust gas purification device (not shown). The discharge channel 27 communicates with the housing section 29 . The discharge flow path 27 is continuous with the accommodating portion 29 in the axial direction. The turbine wheel 17 is disposed in the housing portion 29 . An exhaust flow path 31 is formed on the radially outer side of the housing portion 29 . The housing portion 29 communicates with the exhaust flow path 31 . The exhaust flow path 31 communicates with an exhaust manifold of an engine (not shown). Exhaust gas discharged from an exhaust manifold of an engine (not shown) is guided to the exhaust flow path 27 via the exhaust flow path 31 and the housing portion 29 . The exhaust gas guided from the exhaust flow path 31 to the exhaust flow path 27 via the accommodating portion 29 rotates the turbine wheel 17 during the flow process.

The rotational force of the turbine wheel 17 is transmitted to the compressor impeller 19 via the shaft 15. When the compressor impeller 19 rotates, the air is pressurized as described above. Air is thus directed to the engine intake.

FIG. 2 is a sectional view taken along line AA in FIG. As shown in FIG. 2, the exhaust flow path 31 includes an exhaust gas introduction port 33, an exhaust gas introduction path 35, a turbine scroll flow path 37, and a scroll outlet 39.

The exhaust gas inlet 33 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 exhaust introduction port 33 .

The exhaust gas introduction passage 35 connects the exhaust gas introduction port 33 and the turbine scroll passage 37 . The exhaust gas introduction path 35 is formed, for example, in a straight line. The exhaust gas introduction path 35 guides the exhaust gas introduced from the exhaust gas introduction port 33 to the turbine scroll flow path 37 .

The turbine scroll flow path 37 is communicated with the housing portion 29 via the scroll outlet 39 . Turbine scroll flow path 37 is formed around turbine wheel 17 . The turbine scroll flow path 37 guides the exhaust gas introduced from the exhaust gas introduction path 35 to the housing portion 29 via the scroll outlet 39.

A partition plate 41 is formed in the turbine housing 5 . The partition plate 41 is arranged within the exhaust flow path 31 . Specifically, the partition plate 41 is arranged within the exhaust gas introduction port 33, the exhaust gas introduction path 35, and the turbine scroll flow path 37. The partition plate 41 is connected in the axial direction to the inner surfaces of the exhaust gas introduction port 33, the exhaust gas introduction path 35, and the turbine scroll flow path 37. The partition plate 41 extends along the exhaust flow path 31. That is, the partition plate 41 extends along the flow direction of exhaust gas. Hereinafter, the upstream side in the flow direction of exhaust gas will be simply referred to as the upstream side, and the downstream side in the flow direction of exhaust gas will be simply referred to as the downstream side.

The exhaust gas inlet 33 is divided into an exhaust gas inlet 33a and an exhaust gas inlet 33b in the radial direction by a partition plate 41. The exhaust gas introduction port 33a is located radially inner than the exhaust gas introduction port 33b.

The exhaust gas introduction path 35 is divided into an exhaust gas introduction path 35a and an exhaust gas introduction path 35b in the radial direction by a partition plate 41. The exhaust gas introduction path 35a is located radially inner than the exhaust gas introduction path 35b. The exhaust gas introduction path 35a communicates with the exhaust gas introduction port 33a. The exhaust gas introduction path 35b communicates with the exhaust gas introduction port 33b.

The turbine scroll flow path 37 is divided in the radial direction by a partition plate 41 into a turbine scroll flow path (second scroll flow path) 37a and a turbine scroll flow path (first scroll flow path) 37b. The turbine scroll passage 37a is located radially inside the turbine scroll passage 37b. The turbine scroll passage 37a communicates with the exhaust gas introduction passage 35a. The turbine scroll passage 37b communicates with the exhaust gas introduction passage 35b. The two turbine scroll passages 37a and 37b are wound radially outward with respect to the turbine wheel 17. The two turbine scroll flow paths 37a and 37b are wound so as to approach the turbine wheel 17 as they proceed in the rotation direction RD of the turbine wheel 17. The radial width of each turbine scroll passage 37 decreases from the upstream side to the downstream side.

The two turbine scroll passages 37a and 37b are connected to mutually different circumferential positions on the outer circumferential portion of the housing portion 29, respectively. The turbine scroll flow path 37a communicates with the housing portion 29 via the scroll outlet 39a. The turbine scroll flow path 37b is communicated with the housing portion 29 via the scroll outlet 39b. The two scroll outlets 39a, 39b communicate each of the two turbine scroll passages 37a, 37b with the housing section 29, respectively.

Two scroll outlets 39a and 39b are formed along the circumferential direction. Specifically, the scroll outlet 39a communicates with the accommodating portion 29 over one half circumference of the accommodating portion 29 (specifically, the left half circumference in FIG. 2). The scroll outlet 39b communicates with the accommodating part 29 over the other half of the accommodating part 29 (specifically, the right half of the periphery in FIG. 2). The two scroll outlets 39a and 39b face each other in the radial direction with the turbine wheel 17 in between. In this way, the turbine scroll flow path 37a communicates with the accommodating portion 29 at a different position from the turbine scroll flow path 37b in the rotational direction of the turbine impeller 17.

The turbine housing 5 is formed with a first tongue portion 43a and a second tongue portion 43b. In this embodiment, the shape and size of the first tongue portion 43a are the same as the shape and size of the second tongue portion 43b. Here, the term "same" includes completely the same case and a case where there is deviation from the completely same case within the range of permissible errors (processing accuracy, assembly error, etc.). Hereinafter, the term "same" or "equal" includes both completely the same (equal) and cases where there is deviation from the completely same (equal) within the range of tolerance (processing accuracy, assembly error, etc.) It is. However, the shape and size of the first tongue portion 43a may be different from the shape and size of the second tongue portion 43b. In addition, below, when the 1st tongue part 43a and the 2nd tongue part 43b are not particularly distinguished, they are also simply called the tongue part 43. Each tongue portion 43 partitions the turbine scroll flow path 37a and the turbine scroll flow path 37b. Further, each tongue portion 43 partitions a scroll outlet 39a and a scroll outlet 39b.

The first tongue portion 43a is formed at the downstream end of the partition plate 41. The first tongue portion 43a defines an inner diameter side surface of the turbine scroll passage 37b and an outer diameter side surface of the turbine scroll passage 37a. The first tongue portion 43a defines a downstream end E2a of the scroll outlet 39a and an upstream end E1b of the scroll outlet 39b. The upstream end E1b of the scroll outlet 39b is located on the rotation direction RD side with respect to the first tongue portion 43a. The downstream end E2a of the scroll outlet 39a is located on the opposite side of the rotation direction RD with respect to the first tongue 43a.

The second tongue portion 43b is provided at a position facing the downstream end of the turbine scroll passage 37b. The second tongue portion 43b defines an inner diameter side surface of the turbine scroll passage 37a and an outer diameter side surface of the turbine scroll passage 37b. The second tongue portion 43b defines a downstream end E2b of the scroll outlet 39b and an upstream end E1a of the scroll outlet 39a. The upstream end E1a of the scroll outlet 39a is located on the rotation direction RD side with respect to the second tongue portion 43b. The downstream end E2b of the scroll outlet 39b is located on the opposite side of the rotation direction RD with respect to the second tongue 43b.

The circumferential position of the first tongue portion 43a is shifted by 180° from the circumferential position of the second tongue portion 43b. That is, the first tongue portion 43a and the second tongue portion 43b are opposed to each other in the radial direction with the central axis of the turbine wheel 17 interposed therebetween. However, the circumferential position of the first tongue 43a only needs to be out of phase with respect to the circumferential position of the second tongue 43b, and may be out of phase by an angle different from 180°.

The cross-sectional area of the turbine scroll passages 37a, 37b gradually decreases from the upstream side to the downstream side of the turbine scroll passages 37a, 37b. That is, the flow passage cross-sectional area of the turbine scroll passages 37a and 37b gradually decreases in the rotation direction RD.

In this embodiment, the flow path shape and size of the turbine scroll flow path 37a facing the scroll outlet 39a are the same as the flow path shape and size of the turbine scroll flow path 37b facing the scroll outlet 39b. However, the flow path shape and size of the turbine scroll flow path 37a facing the scroll outlet 39a may be different from the flow path shape and size of the turbine scroll flow path 37b facing the scroll outlet 39b.

The exhaust manifold of the engine (not shown) includes two or more divided passages. Some of the plurality of division paths are connected to the exhaust gas introduction port 33a. Another of the plurality of divided passages is connected to the exhaust gas introduction port 33b. Exhaust gas discharged from an engine (not shown) flows through the split path and is introduced into the exhaust introduction port 33a or the exhaust introduction port 33b. Basically, at the timing when exhaust gas is introduced into one exhaust gas introduction port 33, no exhaust gas is introduced into the other exhaust gas introduction port 33. Introduction of exhaust gas to the exhaust gas introduction port 33a and introduction of exhaust gas to the exhaust gas introduction port 33b are repeated alternately.

The exhaust gas introduced into the exhaust gas introduction port 33a passes through the exhaust gas introduction path 35a and the turbine scroll flow path 37a, and flows from the scroll outlet 39a to the housing portion 29. The exhaust gas introduced into the exhaust gas introduction port 33b passes through the exhaust gas introduction path 35b and the turbine scroll flow path 37b, and flows from the scroll outlet 39b to the housing portion 29. Basically, at the timing when exhaust gas flows into one turbine scroll flow path 37, exhaust gas does not flow into the other turbine scroll flow path 37. Therefore, a pressure difference occurs between the turbine scroll passage 37a and the turbine scroll passage 37b, and a leakage flow of exhaust gas occurs between the two turbine scroll passages 37. In the leakage flow described above, the exhaust gas leaks from one turbine scroll passage 37 to the other turbine scroll passage 37 through the vicinity of the tongue portion 43 .

By suppressing the leakage flow of exhaust gas between the two turbine scroll flow paths 37, it is possible to suppress a decrease in turbine performance. In order to suppress the leakage flow of exhaust gas between the two turbine scroll passages 37, it is necessary to set the length of the tongue portion 43 in the circumferential direction to an appropriate design length. When the circumferential length of the tongue portion 43 is shorter than the designed length, exhaust gas tends to leak between the two turbine scroll passages 37 defined by the tongue portion 43 .

On the other hand, if the length of the tongue portion 43 in the circumferential direction is longer than the designed length, a region where almost no exhaust gas flows will occur between the turbine impeller 17 and the tongue portion 43. When the blades of the turbine wheel 17 pass through this area, the blades of the turbine wheel 17 vibrate. Therefore, it is necessary to set the length of the tongue portion 43 in the circumferential direction to an appropriate design length designed in advance, and to minimize the deviation from the design length as much as possible.

In this embodiment, the turbine housing 5 is cast using a metal mold. The two turbine scroll passages 37 are formed by a core placed inside the mold. At this time, the tongue portion 43 that partitions the two turbine scroll passages 37 is also formed by a core placed inside the mold. The tongue portion 43 is cut by machining after casting the turbine housing 5, and the circumferential length of the tongue portion 43 is determined by the cut surface.

Here, when casting the turbine housing 5, the core may move slightly within the mold. When the core moves within the mold, the position of the tongue portion 43 shifts with respect to the machining surface when the inside of the turbine housing 5 is machined. If the tongue portion 43 deviates from the machined surface in this manner, the length of the tongue portion 43 in the circumferential direction may deviate from the appropriate designed length. In other words, if the tongue portion 43 deviates from the machined surface, the cross-sectional area of the tongue portion 43 on the cutting surface may deviate from the appropriate design cross-sectional area.

Therefore, in the turbine housing 5 of this embodiment, by devising the shape of the tongue portion 43, even when the core moves within the mold and the tongue portion 43 deviates from the machined surface, the tongue portion 43 can be The circumferential length can be maintained at an appropriate design length.

FIG. 3 is a partially enlarged view of the broken line portion shown in FIG. 2. FIG. As shown in FIG. 3, the tongue portion 43b has an upstream end surface 51 and a downstream end surface 53. The upstream end surface 51 includes a downstream end E2b of the scroll outlet 39b. The downstream end surface 53 includes an upstream end E1a of the scroll outlet 39a. Note that the tongue portion 43a (see FIG. 2) has an upstream end surface 51 and a downstream end surface 53 similarly to the tongue portion 43b. Since the shape of the tongue portion 43a is similar to the shape of the tongue portion 43b, the upstream end surface 51 and the downstream end surface 53 of the tongue portion 43b will be described in detail below, and the upstream end surface 51 and the downstream end surface of the tongue portion 43a will be described in detail. Description of the side end surface 53 will be omitted.

The upstream end surface 51 is formed on the upstream side of the tongue portion 43b in the rotational direction RD of the turbine impeller 17. The upstream end surface 51 is constituted by the surface of the outer diameter end on the outer diameter side of the turbine scroll flow path 37b. The downstream end surface 53 is formed on the downstream side of the tongue portion 43b in the rotational direction RD of the turbine impeller 17. The downstream end surface 53 is constituted by the surface of the inner diameter end on the inner diameter side of the turbine scroll passage 37a. The downstream end surface 53 has a surface shape that follows the upstream end surface 51 of the turbine scroll passage 37b. Specifically, the downstream end surface 53 is a surface parallel to the upstream end surface 51.

FIG. 4 is a diagram for explaining the state of the tongue portion 43b shown in FIG. 3 during machining. FIG. 5 is a diagram for explaining the state during machining when the tongue portion 43b shown in FIG. 4 is misaligned. As shown in FIGS. 4 and 5, after casting the turbine housing 5, a portion of the tongue portion 43b formed within the turbine housing 5 is cut by machining. In FIGS. 4 and 5, a part of the tongue portion 43b that is cut by machining is indicated by a broken line. Note that the position of the machined surface 55 in FIG. 4 is the same as the position of the machined surface 55 in FIG.

As shown in FIG. 4, a portion of the tongue portion 43b is cut along a machined surface 55, and a cut surface 55a is formed at a position corresponding to the machined surface 55 of the tongue portion 43b. Similarly, as shown in FIG. 5, a part of the tongue 43b is cut by a machined surface 55, and a cut surface 55a1 is formed at a position corresponding to the machined surface 55 of the tongue 43b.

Here, the tongue portion 43b shown in FIG. 5 is located at a position shifted toward the accommodating portion 29 side with respect to the tongue portion 43b shown in FIG. This positional shift occurs, for example, when the core moves slightly within the mold during casting of the turbine housing 5. The cutting surface 55a1 of the tongue 43b shown in FIG. 5 is located at a different position from the cutting surface 55a of the tongue 43b shown in FIG.

As described above, the downstream end surface 53 is a surface parallel to the upstream end surface 51, and a parallel portion PA is formed between the upstream end surface 51 and the downstream end surface 53 of the tongue portion 43b. When machining the tongue portion 43b, the parallel portion PA of the tongue portion 43b is cut along the machined surface 55. By cutting the parallel portion PA of the tongue portion 43b, even if the tongue portion 43b deviates from the machined surface 55, the length in the circumferential direction of the cut surfaces 55a and 55a1 is maintained at an appropriate design length. be able to. In other words, even if the tongue portion 43b deviates from the machined surface 55 by cutting the parallel portion PA of the tongue portion 43b, the cross-sectional area of the cut surfaces 55a and 55a1 is maintained at the appropriate design cross-sectional area. can do.

Here, in order to suppress a change in the cross-sectional area of the cutting surfaces 55a and 55a1 when the tongue portion 43 deviates from the machined surface, it is also possible to form the tongue portion 43 so as to extend in the radial direction. In other words, in order to suppress changes in the cross-sectional area of the cutting surfaces 55a and 55a1, it is also possible to form the tongue portion 43 so as to extend toward the rotation center axis of the turbine impeller 17. However, in such a case, the upstream end face 51 and the downstream end face 53 of the tongue portion 43 extend in the radial direction, and the flow passage cross-sectional area of the turbine scroll passages 37a, 37b suddenly increases near the tongue portion 43. This can cause deterioration in turbine performance.

Therefore, in this embodiment, it is desirable to suppress both the change in the cross-sectional area of the tongue portion 43 at the cutting surfaces 55a and 55a1 caused by the core displacement and the change in the flow path cross-sectional area of the turbine scroll flow paths 37a and 37b. The purpose is Therefore, in this embodiment, the upstream end surface 51 and the downstream end surface 53 of the tongue portion 43 are parallel surfaces, and the flow path cross-sectional area of the turbine scroll flow paths 37a and 37b is linearly adjusted from the upstream side to the downstream side. It is formed to decrease.

FIG. 6 is a diagram for explaining the relationship between the circumferential position θ of the scroll outlets 39a and 39b and the passage cross-sectional area A of the turbine scroll passages 37a and 37b. Here, the circumferential position θ of the scroll outlet 39 is expressed using the deviation angle θ with respect to the upstream end portions E1a and E1b of the scroll outlet 39. As shown in FIG. 6, for example, if θ=0° at the upstream end E1a of the scroll outlet 39a, θ=180° at the downstream end E2a of the scroll outlet 39a. Further, if θ=0° at the upstream end E1b of the scroll outlet 39b, θ=180° at the downstream end E2b of the scroll outlet 39b.

As shown in FIG. 6, the flow passage cross-sectional area A of the turbine scroll passage 37a varies from the upstream end E1a (θ=0°) to the downstream end E2a (θ=180°) of the scroll outlet 39a. It decreases linearly towards Specifically, the turbine scroll passage 37a has a passage cross-sectional area A1 at the upstream end E1a of the scroll outlet 39a, and has a passage cross-sectional area A2 at the downstream end E2a. The channel cross-sectional area A2 is smaller than the channel cross-sectional area A1. A cross-sectional area A of the turbine scroll passage 37a decreases linearly from a cross-sectional area A1 at the upstream end E1a of the scroll outlet 39a to a cross-sectional area A2 at the downstream end E2a.

Further, the flow passage cross-sectional area A of the turbine scroll passage 37b decreases linearly from the upstream end E1b (θ=0°) to the downstream end E2b (θ=180°) of the scroll outlet 39b. do. Specifically, the turbine scroll passage 37b has a passage cross-sectional area A1 at the upstream end E1b of the scroll outlet 39b, and has a passage cross-sectional area A2 at the downstream end E2b. The channel cross-sectional area A2 is smaller than the channel cross-sectional area A1. The passage cross-sectional area A of the turbine scroll passage 37b decreases linearly from the passage cross-sectional area A1 at the upstream end E1b of the scroll outlet 39b to the passage cross-sectional area A2 at the downstream end E2b.

In this manner, the cross-sectional area of the turbine scroll passages 37a, 37b decreases linearly from the upstream side to the downstream side of the scroll outlets 39a, 39b. Here, the shape of the scroll outlets 39a, 39b is, for example, circular, as shown in FIG. On the other hand, the outer diameter end shapes on the outer diameter side of the turbine scroll passages 37a and 37b are curved shapes with varying curvatures, unlike the circular shapes of the scroll outlets 39a and 39b. The curvature of the curved shape at the outer diameter end of the turbine scroll passages 37a, 37b gradually increases from the upstream side to the downstream side.

That is, the curvature of the curved shape of the outer diameter end of the turbine scroll passages 37a, 37b changes so that the passage cross-sectional area linearly decreases from the upstream side to the downstream side of the scroll outlets 39a, 39b. For example, the radial widths of the outer diameter ends of the turbine scroll passages 37a, 37b and the scroll outlets 39a, 39b decrease linearly from the upstream side to the downstream side. Thereby, the flow velocity of the exhaust gas flowing in the radial direction from the scroll outlets 39a, 39b toward the turbine wheel 17 can be made constant in the rotational direction of the turbine wheel 17.

As described above, according to the present embodiment, the upstream end surface 51 of the tongue portion 43 has a surface on the outer diameter side of the turbine scroll passage 37 in which the passage cross-sectional area decreases linearly. Thereby, the flow velocity of the exhaust gas flowing toward the turbine wheel 17 from the scroll outlets 39a and 39b can be made constant in the rotational direction of the turbine wheel 17.

Further, since the downstream end surface 53 of the tongue portion 43 is a surface parallel to the upstream end surface 51, even if the core moves within the mold and the tongue portion 43 deviates from the machined surface, the tongue portion 43 The circumferential length of can be maintained at an appropriate design length.

FIG. 7 is a diagram for explaining the configuration of a tongue portion 143b according to a modified example of the present disclosure. As shown in FIG. 7, the tongue portion 143b is constituted by a separate member from the turbine housing 5, and is attached after the turbine housing 5 is cast. Similar to the embodiment described above, the tongue portion 143b has an upstream end surface 51 and a downstream end surface 53 that are parallel to each other, and the upstream end surface 51 is connected to the turbine scroll flow path 37 in which the cross-sectional area of the flow path decreases linearly. It has a surface on the outer diameter side. As a result, the same effects as in the above embodiment can be obtained, and the length of the tongue portion 143b in the circumferential direction can be brought closer to the designed length compared to the above embodiment.

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 those skilled in the art can come up with various changes and modifications within the scope of the claims, and it is understood that these naturally fall within the technical scope of the present disclosure. be done.

Although the example in which the turbine T is mounted on the supercharger TC has been described above, the turbine T may be mounted on a device other than the supercharger TC (for example, a generator, etc.).

In the above, an example has been described in which the exhaust introduction port 33a, the exhaust introduction path 35a, and the turbine scroll flow path 37a, and the exhaust gas introduction port 33b, the exhaust gas introduction path 35b, and the turbine scroll flow path 37b are formed side by side in the radial direction. The positional relationship between each component in the exhaust flow path 31 is not limited to this example. For example, the exhaust gas introduction port 33a, the exhaust gas introduction path 35a, and the turbine scroll flow path 37a, and the exhaust gas introduction port 33b, the exhaust gas introduction path 35b, and the turbine scroll flow path 37b may be formed side by side in the axial direction. Further, the number of turbine scroll passages 37a, 37b is not limited to a plurality, and may be one single scroll. In that case, one tongue portion 43 having an upstream end surface 51 and a downstream end surface 53 is formed in the turbine housing 5 . Further, the number of turbine scroll passages 37a, 37b is not limited to two, and may be triple (three passages) or quattro (four passages) in order to further improve the performance of the turbine T. The configuration of the tongue portion 43 described above is applicable regardless of the number of channels in the turbine scroll channel.

5 Turbine housing 17 Turbine impeller 29 Housing portion 37a Turbine scroll flow path (second scroll flow path)
37b Turbine scroll flow path (first scroll flow path)
39a Scroll outlet 39b Scroll outlet 43a First tongue 43b Second tongue 51 Upstream end face 53 Downstream end face E1a Upstream end E1b Upstream end E2a Downstream end E2b Downstream end T Turbine TC supercharger

Claims (4)

a turbine housing in which a scroll passage is formed around a turbine wheel;
a tongue formed in the turbine housing and partitioning an inner diameter side surface and an outer diameter side surface of the scroll flow path;
an upstream end face formed on the upstream side of the tongue in the rotational direction of the turbine wheel, and having a surface on the outer diameter side of the scroll passage where a passage cross-sectional area of the scroll passage decreases linearly;
a downstream end face formed on the downstream side of the tongue in the rotational direction of the turbine wheel and having a surface parallel to the upstream end face;
A turbine equipped with. The turbine housing includes:
comprising a housing portion in which the turbine wheel is arranged;
The scroll flow path is
a first scroll flow path communicating with the storage section;
a second scroll passage that communicates with the accommodating portion at a position different from the first scroll passage in the rotational direction of the turbine wheel;
has
The tongue portion is
a first tongue having the upstream end surface and the downstream end surface and partitioning an inner diameter side surface of the first scroll flow path and an outer diameter side surface of the second scroll flow path;
a second tongue having the upstream end face and the downstream end face and partitioning an inner diameter side surface of the second scroll flow path and an outer diameter side surface of the first scroll flow path;
has,
A turbine according to claim 1. The tongue portion is constituted by a separate member from the turbine housing.
A turbine according to claim 1 or 2. A supercharger comprising the turbine according to any one of claims 1 to 3.

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