Disc wheel

Abstract

To suppress vibration of a disc wheel due to forced vibration.SOLUTION: A disc wheel (turbine impeller 17) comprises: a disk 17a; a plurality of blade bodies 17b that are provided on the outer periphery 17a1 of the disk 17a and arranged at equal intervals in the circumferential direction of the disk 17a; and a plurality of specific-shaped portions 33 that are provided between adjacent blade bodies 17b on the disk 17a and arranged at equal intervals in the circumferential direction, in which the specific-shaped portions 33 have a shape different from other portions between adjacent blade bodies 17b on the disk 17a where the specific-shaped portions 33 are not provided, and the installation number of the specific-shaped portions 33 is a divisor other than 1 of the total number of the blade bodies 17b.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to impellers. [Background technology]

[0002] A force due to the flow of a working fluid acts on an impeller provided in a turbocharger, etc., causing vibration. For example, as described in Patent Document 1, various techniques have been proposed for suppressing vibration of the impeller. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 5-098907 Summary of the Invention [Problem to be solved by the invention]

[0004] Forced vibration caused by periodic external forces is a phenomenon that causes impeller vibration, and new proposals are needed to suppress the impeller vibration caused by forced vibration.

[0005] An object of the present disclosure is to provide a vane wheel that can suppress vibration of the vane wheel due to forced vibration. [Means for solving the problem]

[0006] In order to solve the above problems, the impeller of the present disclosure comprises a disk, a plurality of blades provided on the outer periphery of the disk and arranged at equal intervals circumferentially of the disk, and a plurality of specially shaped portions provided between adjacent blades on the disk and arranged at equal intervals circumferentially, wherein the specially shaped portions have a shape different from other portions of the disk between adjacent blades where no specially shaped portions are provided, and the number of specially shaped portions provided is a divisor other than 1 of the total number of blades.

[0007] The regions of the impeller defined by adjacent blade bodies may include a first region having a first natural frequency and a second region having a second natural frequency different from the first natural frequency.

[0008] The specific shape portion may have a recess formed at the outer edge of the disk that is recessed radially inward, and no recess may be formed in other portions.

[0009] The specific shape portion and the other portion have recesses formed at the outer edge of the disk that are recessed radially inward, and the size of the recesses in the specific shape portion may be different from that in the other portion.

[0010] The specially shaped portion may have a different thickness at the outer edge of the disk compared to other portions.

[0011] The specific shape portion may be located at a different radial position on the outer periphery of the disk compared to other portions. [Effects of the Invention]

[0012] According to the present disclosure, it is possible to suppress vibration of the impeller due to forced vibration. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic cross-sectional view showing a supercharger according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a top view illustrating a turbine wheel according to an embodiment of the present disclosure. [Figure 3] FIG. 3 is a top view showing a turbine wheel according to a first modified example of the present disclosure. [Figure 4] FIG. 4 is a side view showing a turbine wheel according to a second modified example of the present disclosure. [Figure 5] FIG. 5 is a cross-sectional view showing a turbine wheel according to a third modified example of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. Dimensions, materials, and other specific numerical values ​​shown in the embodiments are merely examples for ease of understanding and, unless otherwise specified, do not limit the present disclosure. In this specification and drawings, elements having substantially the same functions and configurations are designated by the same reference numerals to avoid redundant explanation, and elements not directly related to the present disclosure are not shown.

[0015] FIG. 1 is a schematic cross-sectional view showing a turbocharger TC according to this embodiment. In the following description, the direction of arrow L shown in FIG. 1 will be referred to as the left side of the turbocharger TC. The direction of arrow R shown in FIG. 1 will be referred to as the right side of the turbocharger TC. As shown in FIG. 1, the turbocharger TC includes a turbocharger main body 1. The turbocharger 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 mechanism 9. 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 centrifugal compressor C includes the bearing housing 3 and the compressor housing 7.

[0016] A protrusion 3a is provided on the outer peripheral surface of the bearing housing 3. The protrusion 3a is provided on the turbine housing 5 side. The protrusion 3a protrudes in the radial direction of the bearing housing 3. A protrusion 5a is provided on the outer peripheral surface of the turbine housing 5. The protrusion 5a is provided on the bearing housing 3 side. The protrusion 5a protrudes in the radial direction of the turbine housing 5. The bearing housing 3 and the turbine housing 5 are band-fastened by a fastening mechanism 9. The fastening mechanism 9 is, for example, a G-coupling. The fastening mechanism 9 clamps the protrusion 3a and the protrusion 5a.

[0017] A bearing hole 3b is formed in the bearing housing 3. The bearing hole 3b penetrates the turbocharger TC in the left-right direction. A bearing 13 is disposed in the bearing hole 3b. The bearing 13 rotatably supports the shaft 15. The bearing 13 is a plain bearing. However, the present invention is not limited to this, and the bearing 13 may be a rolling bearing. 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 wheel 19 is provided at the right end of the shaft 15. The compressor wheel 19 is rotatably housed in the compressor housing 7.

[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 flow path 23 is formed by the opposing surfaces of the bearing housing 3 and the compressor housing 7. The diffuser flow path 23 pressurizes the air. The diffuser flow path 23 is formed in an annular shape. The diffuser flow path 23 communicates with the intake port 21 on its radially inner side via the compressor impeller 19.

[0019] A compressor scroll passage 25 is provided 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 is connected to an intake port of the engine (not shown) and the diffuser passage 23. When the compressor impeller 19 rotates, air is drawn into the compressor housing 7 through the intake port 21. The drawn air is pressurized and accelerated as it flows 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] A discharge port 27 is formed in the turbine housing 5. The discharge port 27 opens to the left side of the turbocharger TC. The discharge port 27 is connected to an exhaust gas purification device (not shown). A communication passage 29 and a turbine scroll passage 31 are formed in the turbine housing 5. The turbine scroll passage 31 is formed in an annular shape. The turbine scroll passage 31 is formed radially outward of the turbine wheel 17. The turbine scroll passage 31 communicates with a gas inlet (not shown). Exhaust gas discharged from an exhaust manifold of the engine (not shown) is introduced to the gas inlet. The communication passage 29 connects the turbine scroll passage 31 with the discharge port 27 via the turbine wheel 17. The exhaust gas introduced from the gas inlet to the turbine scroll passage 31 is introduced to the discharge port 27 via the communication passage 29 and the turbine wheel 17. The exhaust gas introduced to the discharge port 27 rotates the turbine wheel 17 during its flow.

[0021] 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, and the air is then guided to the intake port of the engine.

[0022] The turbine impeller 17 includes a disk 17a and a plurality of blades 17b. The disk 17a is connected to the left end of the shaft 15. The disk 17a has a substantially cylindrical shape. The disk 17a is arranged coaxially with the shaft 15. A plurality of blades 17b are provided on an outer circumferential portion 17a1 of the disk 17a. The outer diameter of the disk 17a increases toward the right side of the turbocharger TC. The portion of the outer circumferential portion 17a1 of the disk 17a where the outer diameter is greatest corresponds to an outer edge portion 17a2 of the disk 17a. The outer edge portion 17a2 of the disk 17a is located on the outer circumferential portion 17a1 of the disk 17a to the right side of the turbocharger TC.

[0023] A force due to the flow of exhaust gas acts on the turbine wheel 17, causing vibration. In this embodiment, the turbine wheel 17 is designed to suppress vibration of the turbine wheel 17 due to forced vibration. However, the turbine wheel 17 is merely one example of a wheel whose vibration is suppressed. As will be described later, the wheel whose vibration is suppressed is not limited to the turbine wheel 17. The turbine wheel 17 will be described in detail below with reference to FIG. 2.

[0024] Hereinafter, the axial direction, circumferential direction, and radial direction of the turbine wheel 17 will also be simply referred to as the axial direction, circumferential direction, and radial direction. The axial direction, circumferential direction, and radial direction of the turbine wheel 17 coincide with the axial direction, circumferential direction, and radial direction of the disk 17a.

[0025] FIG. 2 is a top view showing the turbine wheel 17 according to this embodiment. FIG. 2 is a view of the turbine wheel 17 as seen from the left side of the turbocharger TC. As shown in FIG. 2, a plurality of blade bodies 17b are arranged at equal intervals in the circumferential direction of the disk 17a. Each blade body 17b extends radially from the outer circumferential portion 17a1 of the disk 17a while twisting in the circumferential direction. In the example of FIG. 2, the total number of blade bodies 17b is eight. However, the total number of blade bodies 17b may be other than eight.

[0026] The disk 17a is provided with a plurality of specially shaped portions 33. The specially shaped portions 33 are provided between adjacent blade bodies 17b on the disk 17a. The specially shaped portions 33 have a shape different from that of other portions of the disk 17a between adjacent blade bodies 17b where the specially shaped portions 33 are not provided.

[0027] The specially shaped portion 33 has a recessed portion 35 formed at the outer edge 17a2 of the disk 17a, recessed radially inward. On the other hand, no recessed portion 35 is formed in the other portion of the disk 17a between adjacent blade bodies 17b where the specially shaped portion 33 is not provided. In the recessed portion 35, the outer diameter of the disk 17a decreases and then increases as it progresses in the circumferential direction. When viewed in the axial direction of the disk 17a, the recessed portion 35 has, for example, an arc shape. The recessed portion 35 is also called a scallop. The scallop is provided to reduce the moment of inertia of the turbine wheel 17 and improve rotational acceleration performance.

[0028] The specially shaped portions 33 are provided at equal intervals in the circumferential direction on the disk 17a. The number of specially shaped portions 33 provided is a divisor of the total number of blade bodies 17b other than 1. In the example of FIG. 2, the number of specially shaped portions 33 provided is four. Note that the four specially shaped portions 33 in this embodiment have the same shape as each other. However, the number of specially shaped portions 33 provided may be other than four. For example, the number of specially shaped portions 33 provided may be two. Furthermore, the angular range in the circumferential direction of the region where the specially shaped portions 33 are formed may be smaller than the angular range in the circumferential direction of the region where the specially shaped portions 33 are not formed.

[0029] 2, regions where the specific shape portion 33 is provided between adjacent blade bodies 17b and regions where the specific shape portion 33 is not provided between adjacent blade bodies 17b are alternately arranged in the circumferential direction. In other words, regions where the recessed portion 35 is formed between adjacent blade bodies 17b and regions where the recessed portion 35 is not formed between adjacent blade bodies 17b are alternately arranged in the circumferential direction.

[0030] The regions of the turbine wheel 17 defined by adjacent blade bodies 17b include a first region R1 where the specific shape portion 33 is provided and a second region R2 where the specific shape portion 33 is not provided. The regions of the turbine wheel 17 defined by adjacent blade bodies 17b include, for example, two adjacent blade bodies 17b and a portion of the disk 17a between the two blade bodies 17b. The first region R1 and the second region R2 are alternately arranged in the circumferential direction. The first region R1 has a first natural frequency. The second region R2 has a second natural frequency. The first region R1 and the second region R2 differ in the presence or absence of the specific shape portion 33, so the first natural frequency and the second natural frequency are different from each other.

[0031] As described above, the turbine wheel 17 according to this embodiment comprises the disk 17a, a plurality of blade bodies 17b provided on the outer circumferential portion 17a1 of the disk 17a and arranged at equal intervals in the circumferential direction of the disk 17a, and a plurality of specially shaped portions 33 provided between adjacent blade bodies 17b on the disk 17a and arranged at equal intervals in the circumferential direction, wherein the specially shaped portions 33 have a shape different from other portions of the disk 17a between adjacent blade bodies 17b where the specially shaped portions 33 are not provided, and the number of the specially shaped portions 33 provided is a divisor of the total number of blade bodies 17b other than 1. As a result, the number of periodic structures arranged in the circumferential direction in the turbine wheel 17 is smaller than the total number of blade bodies 17b.

[0032] For example, if the disk 17a were not provided with the specific shape portion 33, one region divided by adjacent blade bodies 17b in the turbine impeller 17 would be a periodic structure. Therefore, the number of periodic structures would be the total number of blade bodies 17b. On the other hand, in the example of FIG. 2, the region including the first region R1 and the second region R2 adjacent to the first region R1 would be a periodic structure. Therefore, the number of periodic structures would be four, which is fewer than the total number of blade bodies 17b (eight).

[0033] The vibratory stress generated in the turbine wheel 17 due to forced vibration is due to the actual variation in mechanical properties between the blade bodies 17b, and is therefore larger than in an ideal case where there is no variation in mechanical properties between the blade bodies 17b. It is known that the magnification of the actual vibratory stress relative to the vibratory stress in the ideal case increases as the number of periodic structures increases. For example, it is known from Whitehead's theory and the like that the magnification of the actual vibratory stress relative to the vibratory stress in the ideal case is at most √(N+2) / 2, where N is the number of periodic structures.

[0034] As described above, according to the turbine wheel 17 of this embodiment, the number of periodic structures arranged in the circumferential direction of the turbine wheel 17 is smaller than the total number of blade bodies 17b. This makes it possible to reduce the magnification of the actual vibratory stress relative to the vibratory stress in an ideal case where there is no variation in the mechanical properties of each blade body 17b. Therefore, it is possible to suppress vibration of the turbine wheel 17 due to forced vibration.

[0035] In particular, in the turbine wheel 17 according to this embodiment, the regions defined by adjacent blade bodies 17b in the turbine wheel 17 include a first region R1 having a first natural frequency and a second region R2 having a second natural frequency different from the first natural frequency. This appropriately achieves making the region including the first region R1 and the second region R2 a periodic structure arranged in the circumferential direction of the turbine wheel 17. This appropriately achieves making the number of periodic structures arranged in the circumferential direction of the turbine wheel 17 smaller than the total number of blade bodies 17b. This appropriately achieves suppression of vibration of the turbine wheel 17 due to forced vibration.

[0036] In particular, in the turbine wheel 17 according to this embodiment, the specific-shape portion 33 has a recessed portion 35 formed in the outer edge portion 17a2 of the disk 17a, which is recessed radially inward. The recessed portion 35 is not formed in the other portion between adjacent blade bodies 17b on the disk 17a where the specific-shape portion 33 is not provided. This appropriately makes it possible to differentiate the shape of the specific-shape portion 33 from the shape of the other portion. Therefore, it is appropriately made possible to make the number of periodic structures arranged in the circumferential direction of the turbine wheel 17 smaller than the total number of blade bodies 17b. This appropriately makes it possible to suppress the vibration of the turbine wheel 17 due to forced vibration.

[0037] In the above example, the difference between the specially shaped portion 33 and the other portion of the disk 17a between the adjacent blades 17b where the specially shaped portion 33 is not provided is the presence or absence of the recessed portion 35. However, the specially shaped portion 33 is not limited to the above example. Hereinafter, various modified examples in which the specially shaped portion 33 differs from the above example will be described with reference to Figures 3 to 5.

[0038] Fig. 3 is a top view showing a turbine wheel 17A according to a first modified example. Fig. 3 is a view of the turbine wheel 17A as seen from the left side of the turbocharger TC. Like the turbine wheel 17 described above, the turbine wheel 17A includes a disk 17a and eight blade bodies 17b. However, like the turbine wheel 17 described above, the total number of blade bodies 17b may be other than eight.

[0039] In the turbine impeller 17A, a plurality of specific-shape portions 33A are provided on the disk 17a. The specific-shape portions 33A are provided between adjacent blade bodies 17b on the disk 17a. The specific-shape portions 33A have a shape different from other portions of the disk 17a between adjacent blade bodies 17b where the specific-shape portions 33A are not provided.

[0040] The shaped portion 33A has a recess 35 formed in the outer edge 17a2 of the disk 17a, recessed radially inward. Hereinafter, the recess 35 formed in the shaped portion 33A will also be referred to as recess 35-1. Unlike the turbine wheel 17 described above, the turbine wheel 17A also has a recess 35 formed in a portion between adjacent blade bodies 17b on the disk 17a where the shaped portion 33A is not provided. Hereinafter, the recess 35 formed in the other portion will also be referred to as recess 35-2.

[0041] The size of the recess 35 in the specific-shape portion 33A is different from that in other portions of the disk 17a between adjacent blades 17b where the specific-shape portion 33A is not provided. In the example of FIG. 3, the recess 35-1 formed in the specific-shape portion 33A is larger than the recess 35-2 formed in the other portion. For example, the curvature of the recess 35-1 is larger than the curvature of the recess 35-2. Therefore, the minimum distance between the recess 35-1 and the central axis of the disk 17a is shorter than the minimum distance between the recess 35-2 and the central axis of the disk 17a.

[0042] 3, regions where recesses 35-1 are formed between adjacent blade bodies 17b and regions where recesses 35-2 are formed between adjacent blade bodies 17b are alternately arranged in the circumferential direction. In other words, regions where specific shape portions 33A are provided between adjacent blade bodies 17b and regions where specific shape portions 33A are not provided between adjacent blade bodies 17b are alternately arranged in the circumferential direction.

[0043] As described above, the specially shaped portions 33A are provided at equal intervals in the circumferential direction on the disk 17a, similar to the specially shaped portions 33 described above. The number of specially shaped portions 33A provided is a divisor of the total number of blade bodies 17b other than 1, similar to the specially shaped portions 33 described above. In the example of FIG. 3, the number of specially shaped portions 33A provided is four. However, the number of specially shaped portions 33A provided may be other than four. For example, the number of specially shaped portions 33A provided may be two.

[0044] In the turbine wheel 17A, the first region R1 in which the specific shape portion 33A is provided and the second region R2 in which the specific shape portion 33A is not provided are arranged alternately in the circumferential direction, similar to the above-described turbine wheel 17. Because the presence or absence of the specific shape portion 33A differs between the first region R1 and the second region R2, the first natural frequency of the first region R1 and the second natural frequency of the second region R2 are different from each other.

[0045] As described above, in the turbine wheel 17A according to the first modification, recesses 35 recessed radially inward are formed in the outer edge 17a2 of the disk 17a in the specific-shape portion 33A and in the other portions of the disk 17a between adjacent blade bodies 17b where the specific-shape portion 33A is not provided. The size of the recesses 35 in the specific-shape portion 33A is different from that in the other portions. This appropriately makes it possible to differentiate the shape of the specific-shape portion 33A from the shape of the other portions. Therefore, it is appropriately made possible to make the number of periodic structures arranged in the circumferential direction of the turbine wheel 17A smaller than the total number of blade bodies 17b. This appropriately makes it possible to suppress vibration of the turbine wheel 17A due to forced vibration.

[0046] Fig. 4 is a side view showing a turbine wheel 17B according to a second modified example. Fig. 4 is a view of the turbine wheel 17B viewed in the radial direction. Like the turbine wheel 17 described above, the turbine wheel 17B includes a disk 17a and eight blade bodies 17b. However, like the turbine wheel 17 described above, the total number of blade bodies 17b may be other than eight.

[0047] In the turbine impeller 17B, a plurality of specific-shape portions 33B are provided on the disk 17a. The specific-shape portions 33B are provided between adjacent blade bodies 17b on the disk 17a. The specific-shape portions 33B have a shape different from other portions of the disk 17a between adjacent blade bodies 17b where the specific-shape portions 33B are not provided.

[0048] In the specific-shape portion 33B, the thickness of the outer edge portion 17a2 of the disk 17a is different from that of other portions between adjacent blade bodies 17b on the disk 17a where the specific-shape portion 33B is not provided. The thickness of the outer edge portion 17a2 of the disk 17a corresponds to the length of the outer edge portion 17a2 in the axial direction of the disk 17a. In the example of FIG. 4, the thickness of the outer edge portion 17a2 of the disk 17a in the specific-shape portion 33B is thicker than the other portions. In the portions where the thickness of the outer edge portion 17a2 of the disk 17a changes, the thickness of the outer edge portion 17a2 changes gradually, suppressing a decrease in the aerodynamic performance of the turbine wheel 17B.

[0049] 4, the thickness of the outer edge 17a2 of the disk 17a is substantially constant regardless of the circumferential position in the specific shaped portion 33B and the other portions. However, the thickness of the outer edge 17a2 of the disk 17a may vary depending on the circumferential position in at least one of the specific shaped portion 33B and the other portions. The thickness of the outer edge 17a2 of the disk 17a may be consistent in some regions of the specific shaped portion 33B and some regions of the other portions.

[0050] The specific-shaped portions 33B are provided at equal intervals in the circumferential direction of the disk 17a, similar to the specific-shaped portions 33 described above. The number of the specific-shaped portions 33B provided is a divisor of the total number of blade bodies 17b other than 1, similar to the specific-shaped portions 33 described above. In the example of FIG. 4, the number of the specific-shaped portions 33B provided is four. However, the number of the specific-shaped portions 33B provided may be other than four. For example, the number of the specific-shaped portions 33B provided may be two.

[0051] 4, regions where the specific shape portion 33B is provided between adjacent blade bodies 17b and regions where the specific shape portion 33B is not provided between adjacent blade bodies 17b are alternately arranged in the circumferential direction. In other words, regions where the thickness of the outer edge portion 17a2 of the disk 17a is thicker between adjacent blade bodies 17b and regions where the thickness of the outer edge portion 17a2 of the disk 17a is thinner between adjacent blade bodies 17b are alternately arranged in the circumferential direction.

[0052] In the turbine wheel 17B, the first region R1 where the specific shape portion 33B is provided and the second region R2 where the specific shape portion 33B is not provided are arranged alternately in the circumferential direction, similar to the above-described turbine wheel 17. Because the presence or absence of the specific shape portion 33B differs between the first region R1 and the second region R2, the first natural frequency of the first region R1 and the second natural frequency of the second region R2 are different from each other.

[0053] As described above, in the turbine wheel 17B according to the second modification, the thickness of the outer edge portion 17a2 of the disk 17a is different in the specific-shape portion 33B compared to the other portions of the disk 17a between adjacent blade bodies 17b where the specific-shape portion 33B is not provided. This appropriately makes it possible to differentiate the shape of the specific-shape portion 33B from the shape of the other portions. Therefore, it is appropriately made possible to make the number of periodic structures arranged in the circumferential direction of the turbine wheel 17B smaller than the total number of blade bodies 17b. This appropriately makes it possible to suppress the vibration of the turbine wheel 17B due to forced vibration.

[0054] Fig. 5 is a cross-sectional view showing a turbine wheel 17C according to a third modified example. Fig. 5 is a cross-sectional view of a portion of the turbine wheel 17C viewed in the radial direction. Like the turbine wheel 17 described above, the turbine wheel 17C includes a disk 17a and eight blade bodies 17b. However, like the turbine wheel 17 described above, the total number of blade bodies 17b may be other than eight.

[0055] In the turbine impeller 17C, a plurality of specific-shape portions 33C are provided on the disk 17a. The specific-shape portions 33C are provided between adjacent blade bodies 17b on the disk 17a. The specific-shape portions 33C have a shape different from other portions of the disk 17a between adjacent blade bodies 17b where the specific-shape portions 33C are not provided.

[0056] In FIG. 5, the outer circumferential portion 17a1 of the disk 17a in the portion between adjacent blade bodies 17b on the disk 17a where the specific-shaped portion 33C is not provided is indicated by a solid line. On the other hand, the outer circumferential portion 17a1 of the disk 17a in the specific-shaped portion 33C is indicated by a two-dot chain line. The radial position of the outer circumferential portion 17a1 of the disk 17a in the specific-shaped portion 33C is different from that in the other portions. The radial position of the outer circumferential portion 17a1 of the disk 17a corresponds to the outer diameter of the outer circumferential portion 17a1 of the disk 17a. In the example of FIG. 5, the radial position of the outer circumferential portion 17a1 of the disk 17a in the specific-shaped portion 33C is radially outward compared to the radial position of the outer circumferential portion 17a1 of the disk 17a in the other portions. In other words, the outer diameter of the outer circumferential portion 17a1 of the disk 17a in the specific-shaped portion 33C is larger than the outer diameter of the outer circumferential portion 17a1 of the disk 17a in the other portions.

[0057] 5, the radial position of the outer circumferential portion 17a1 of the disk 17a in the specific shaped portion 33C is radially outward in all axial positions compared to the radial position of the outer circumferential portion 17a1 of the disk 17a in the other portions. However, the radial position of the outer circumferential portion 17a1 of the disk 17a in the specific shaped portion 33C and the radial position of the outer circumferential portion 17a1 of the disk 17a in the other portions may coincide at some axial positions.

[0058] The specially shaped portions 33C are provided at equal intervals in the circumferential direction of the disk 17a, similar to the specially shaped portions 33 described above. The number of specially shaped portions 33C provided is a divisor of the total number of blade bodies 17b other than 1, similar to the specially shaped portions 33 described above. For example, the number of specially shaped portions 33C provided is four. However, the number of specially shaped portions 33C provided may be other than four. For example, the number of specially shaped portions 33C provided may be two.

[0059] For example, regions where the specific shape portion 33C is provided between adjacent blade bodies 17b and regions where the specific shape portion 33C is not provided between adjacent blade bodies 17b are alternately arranged in the circumferential direction. In this case, regions where the outer diameter of the outer circumferential portion 17a1 of the disk 17a is larger between adjacent blade bodies 17b and regions where the outer diameter of the outer circumferential portion 17a1 of the disk 17a is smaller between adjacent blade bodies 17b are alternately arranged in the circumferential direction.

[0060] In the turbine wheel 17C, for example, the first region R1 in which the specific shaped portion 33C is provided and the second region R2 in which the specific shaped portion 33C is not provided are arranged alternately in the circumferential direction, similar to the above-described turbine wheel 17. Because the presence or absence of the specific shaped portion 33C differs between the first region R1 and the second region R2, the first natural frequency of the first region R1 and the second natural frequency of the second region R2 are different from each other.

[0061] As described above, in the turbine wheel 17C according to the third modification, the specific-shape portion 33C is located at a different radial position on the outer circumferential portion 17a1 of the disk 17a than the other portions of the disk 17a between adjacent blade bodies 17b where the specific-shape portion 33C is not provided. This appropriately makes it possible to differentiate the shape of the specific-shape portion 33C from the shapes of the other portions. Therefore, it is appropriately made possible to make the number of periodic structures arranged in the circumferential direction of the turbine wheel 17C smaller than the total number of blade bodies 17b. This appropriately makes it possible to suppress the vibration of the turbine wheel 17C due to forced vibration.

[0062] 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 conceive of various modifications and alterations within the scope of the claims, and it is understood that such modifications and alterations also fall within the technical scope of the present disclosure.

[0063] The above describes the specific-shaped portion 33, the specific-shaped portion 33A, the specific-shaped portion 33B, and the specific-shaped portion 33C. However, the specific-shaped portion 33, the specific-shaped portion 33A, the specific-shaped portion 33B, and the specific-shaped portion 33C may be combined as appropriate. For example, in the specific-shaped portion 33 or the specific-shaped portion 33A, the outer edge portion 17a2 of the disk 17a may have a different thickness than the other portions, as in the specific-shaped portion 33B. For example, in the specific-shaped portion 33 or the specific-shaped portion 33A, the outer edge portion 17a1 of the disk 17a may have a different radial position than the other portions, as in the specific-shaped portion 33C. For example, in the specific-shaped portion 33 or the specific-shaped portion 33A, the outer edge portion 17a2 of the disk 17a may have a different thickness than the other portions, as in the specific-shaped portion 33B, and the outer edge portion 17a1 of the disk 17a may have a different radial position than the other portions, as in the specific-shaped portion 33C.

[0064] In the above, an example has been described in which the impeller whose vibration is to be suppressed is the turbine wheel 17 of the turbocharger TC described with reference to Fig. 1. However, the impeller whose vibration is to be suppressed and to which the above-mentioned measures are applied may also be the compressor wheel 19. The turbine T described above is a radial turbine in which gas flows into the turbine wheel 17 from the radially outer side. However, the impeller whose vibration is to be suppressed and to which the above-mentioned measures are applied may also be the turbine wheel of a mixed-flow turbine in which gas flows in a direction inclined from the radial direction relative to the turbine wheel, or the turbine wheel of an axial-flow turbine in which gas flows in the axial direction relative to the turbine wheel. [Explanation of symbols]

[0065] 17 Turbine wheel (impeller) 17A Turbine wheel (impeller) 17B Turbine wheel (impeller) 17C Turbine wheel (impeller) 17a disc 17a1 Outer periphery 17a2 Outer edge 17b Wing body 33 Specific shape part 33A Specific shape part 33B Specific shape part 33C Specific shape part 35 recess 35-1 Recessed part 35-2 Recessed part R1 1st area R2 2nd area

Claims

1. The disk and a plurality of blades provided on an outer periphery of the disk and arranged at equal intervals in a circumferential direction of the disk; a plurality of specially shaped portions provided between adjacent blade bodies on the disk and arranged at equal intervals in the circumferential direction, the specially shaped portions having a shape different from other portions of the disk between adjacent blade bodies where the specially shaped portions are not provided, and the number of the specially shaped portions provided is a divisor other than 1 of the total number of blade bodies; Equipped with wing wheel.

2. The regions divided by the adjacent blade bodies in the blade wheel include a first region having a first natural frequency and a second region having a second natural frequency different from the first natural frequency. The impeller according to claim 1 .

3. The specific shape portion has a recessed portion recessed radially inward at an outer edge of the disk, The recessed portion is not formed in the other portion. The impeller according to claim 1 .

4. a recessed portion recessed radially inward at an outer edge of the disk is formed in the specific shape portion and the other portion, The size of the recessed portion in the specific shape portion is different from that of the other portion. The impeller according to claim 1 .

5. The specific shape portion has a thickness different from that of the other portion at the outer edge of the disk.

5. The impeller according to claim 1, 3 or 4.

6. The specific shape portion is different from the other portion in the radial direction of the outer periphery of the disk.

5. The impeller according to claim 1, 3 or 4.

Images