Electric turbo machine

Abstract

This electric turbo machine for a refrigerator includes a motor and a turbine coupled to the motor via a rotation shaft. The turbine includes a fixed vane provided on an upstream side of a turbine wheel in a refrigerant flow path. A casing includes a partition portion configured to partition the motor and the refrigerant flow path of the turbine. The partition portion is provided with a heat insulation mechanism. The fixed vane is fixed to a shroud-side flow path wall.

Description

Electric Turbomachinery

[0001] This application claims priority to Japanese Patent Application No. 2024-015170, filed with the Japan Patent Office on February 2, 2024, the contents of which are incorporated herein by reference.

[0002] Patent Document 1 discloses a turbine structure with a variable nozzle for a helium refrigeration system, in which variable nozzle vanes are supported on a casing on the hub side via support pins.

[0003] Japanese Patent Application Laid-Open No. 2001-152808

[0004] The inventors of the present application have been considering providing an insulating mechanism in a partition that separates the motor from the refrigerant flow path of the turbine to suppress heat input from the motor to the refrigerant flowing through the refrigerant flow path of the turbine, in order to improve the operating efficiency of an electric turbomachine for a chiller, which includes a turbine connected to a motor. However, if a fixed vane is provided upstream of the turbine wheel in an electric turbomachine equipped with the insulating mechanism, if the fixed vane is fixed to the partition side, the design freedom of the structure for fixing the fixed vane is likely to be reduced due to the insulating mechanism.

[0005] In view of the above circumstances, at least one embodiment of the present disclosure aims to provide an electric turbomachine for a refrigerator equipped with an insulating mechanism for suppressing heat input from a motor to a refrigerant flowing through a refrigerant passage of the turbine, the electric turbomachine having a high degree of freedom in designing a structure for fixing fixed vanes to a casing.

[0006] In order to achieve the above object, an electric turbomachine according to at least one embodiment of the present disclosure is an electric turbomachine for a refrigerator, comprising: a motor; and a turbine connected to the motor via a rotating shaft; the turbine including: a turbine wheel; a casing that houses the turbine wheel and forms a refrigerant flow path through which a refrigerant flows; and a fixed vane provided upstream of the turbine wheel in the refrigerant flow path; the casing includes a partition configured to separate the motor from the refrigerant flow path of the turbine, and the partition is provided with a heat insulating mechanism for suppressing heat input from the motor to the refrigerant flowing through the refrigerant flow path; the refrigerant flow path includes a scroll flow path provided on an outer circumferential side of the turbine wheel, and an intermediate flow path provided between the scroll flow path and the turbine wheel; the casing includes a motor-side flow path wall that forms a flow path wall surface on the motor side of the intermediate flow path, and a shroud-side flow path wall that forms a flow path wall surface on the opposite side to the motor of the intermediate flow path, and the fixed vane is fixed to the shroud-side flow path wall.

[0007] According to at least one embodiment of the present disclosure, there is provided an electric turbomachine for a refrigerator equipped with an insulating mechanism for suppressing heat input from a motor to a refrigerant flowing through a refrigerant passage of a turbine, the electric turbomachine having a high degree of freedom in designing a structure for fixing fixed vanes to a casing.

[0008] FIG. 1 is a diagram schematically illustrating a schematic configuration of an electric turbomachine 2 according to an embodiment of the present disclosure. FIG. 1 is a schematic cross-sectional view illustrating an example of a cross section along the axial direction of the turbine 8 of the electric turbomachine 2 shown in FIG. 1 . FIG. 2 is a schematic partial cross-sectional view illustrating an example of a specific configuration of the X portion of FIG. 2 . FIG. 3 is a schematic partial cross-sectional view illustrating yet another example of the specific configuration of the X portion of FIG. 2 . FIG. 4 is a schematic partial cross-sectional view illustrating a modified example of the electric turbomachine 2 shown in FIG. 5 . FIG. 5 is a schematic cross-sectional view illustrating another example of a cross section along the axial direction of the turbine 8 of the electric turbomachine 2 shown in FIG. 1 . FIG. 6 is a schematic cross-sectional view illustrating a modified example of the electric turbomachine 2 shown in FIG. 8 . FIG. 9 is a diagram illustrating an arrangement of fixed vanes 26 and the like in the electric turbomachine 2 shown in FIG. 9 when viewed in the axial direction. FIG. 10 is a schematic cross-sectional view illustrating a modified example of the electric turbomachine 2 shown in FIG. 3 . FIG. 11 is a schematic cross-sectional view illustrating a modified example of the electric turbomachine 2 shown in FIG. 3 . FIG. 15 is a diagram showing an example of the positional relationship between the fixed vanes 26 and the outlet 90b of the bypass flow passage 90 as viewed in the axial direction for the electric turbo machine 2 shown in FIG. 14 . FIG. 16 is a diagram showing an example of the positional relationship between the fixed vanes 26 and the outlet 90b of the bypass flow passage 90 as viewed in the axial direction for the electric turbo machine 2 shown in FIG. 15 . FIG. 17 is a diagram showing an example of the positional relationship between the fixed vanes 26 and the outlet 90b of the bypass flow passage 90 as viewed in the axial direction for the electric turbo machine 2 shown in FIG. 16 . FIG. 18 is a diagram showing another example of the positional relationship between the fixed vanes 26 and the outlet 90b of the bypass flow passage 90 as viewed in the axial direction for the electric turbo machine 2 shown in FIG. 16 . FIG. 19 is a diagram showing an example of the positional relationship between the fixed vanes 26 and the outlet 90b of the bypass flow passage 90 as viewed in the axial direction for the electric turbo machine 2 shown in FIG. 16 .

[0009] Several embodiments of the present disclosure will be described below with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of components described as embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the invention. For example, expressions expressing relative or absolute arrangements, such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial," not only strictly express such arrangements, but also express relative displacements with a tolerance or angle or distance to the extent that the same function is achieved. For example, expressions expressing the equality of things, such as "same," "equal," and "homogeneous," not only express strict equality, but also express tolerance or differences to the extent that the same function is achieved. For example, expressions expressing shapes such as a square or cylindrical shape not only express shapes such as a square or cylindrical shape in the strict geometric sense, but also express shapes including concave and convex portions, chamfered portions, etc., to the extent that the same effect is achieved. On the other hand, the expressions "comprise," "include," "have," "includes," or "have" of one element are not exclusive expressions that exclude the presence of other elements.

[0010] Fig. 1 is a diagram schematically illustrating a general configuration of an electric turbo machine 2 according to an embodiment of the present disclosure. The electric turbo machine 2 illustrated in Fig. 1 is an electric turbo machine for a refrigerator, and includes a motor 4, a turbine 8 connected to the motor 4 via a rotating shaft 6A, and a compressor 10 connected to the motor 4 via a rotating shaft 6B.

[0011] The motor 4 includes a rotor 12 and a stator 14. One end of the rotor 12 is connected to a turbine wheel 18 of the turbine 8 via a rotating shaft 6A, and the other end of the rotor 12 is connected to a compressor impeller 20 of the compressor 10 via a rotating shaft 6B, so that the rotor 12, turbine wheel 18, and compressor impeller 20 rotate integrally. The rotating shaft 6A is rotatably supported by a turbine-side bearing 16A, and the rotating shaft 6B is rotatably supported by a compressor-side bearing 16B.

[0012] In the following description, unless otherwise specified, the term "axial direction" means the axial direction of the electric turbo machine 2, i.e., the axial direction of the turbine wheel 18; the term "radial direction" means the radial direction of the electric turbo machine 2, i.e., the radial direction of the turbine wheel 18; and the term "circumferential direction" means the circumferential direction of the electric turbo machine 2, i.e., the circumferential direction of the turbine wheel 18, unless otherwise specified.

[0013] Figure 2 is a schematic cross-sectional view showing an example of a cross section along the axial direction of the turbine 8 of the electric turbomachine 2 shown in Figure 1. In the exemplary embodiment shown in Figure 2, the turbine 8 includes a turbine wheel 18, a casing 24 that houses the turbine wheel 18 and forms a coolant flow path 22 through which a coolant flows, and stationary vanes 26 that are provided upstream of the turbine wheel 18 in the coolant flow path 22. The type of coolant that flows through the coolant flow path 22 is not particularly limited, and may be, for example, a gas such as air.

[0014] The turbine wheel 18 includes a hub 28 and a plurality of turbine blades 30 spaced apart in the circumferential direction on the outer circumferential surface of the hub 28 .

[0015] The refrigerant flow path 22 includes a scroll flow path 32 formed on the outer periphery of the turbine wheel 18, a wheel flow path 34 in which the turbine wheel 18 is disposed, and an intermediate flow path 36 connecting the scroll flow path 32 and the wheel flow path 34. The intermediate flow path 36 is provided between the scroll flow path 32 and the turbine wheel 18, and is formed in an annular shape so as to guide the refrigerant flowing through the scroll flow path 32 to the turbine wheel 18 located on the inner periphery of the scroll flow path 32.

[0016] The casing 24 includes a turbine housing 40 that houses the turbine wheel 18 and forms at least a portion of the scroll flow path 32, a bearing housing 42 that houses the turbine side bearing 16A, and a nozzle mount 44 that forms the intermediate flow path 36 between the bearing housing 42.

[0017] In the exemplary embodiment shown in FIG. 2 , the turbine housing 40 includes a scroll section 46 that forms the scroll flow passage 32, a flange section 48 that protrudes radially outward from a portion of the scroll section 46 that is adjacent to the bearing housing 42, a nozzle mount support section 50 that supports the nozzle mount 44, and a cylindrical section 52 that forms the outlet of the turbine 8.

[0018] The bearing housing 42 is configured in an annular shape to surround the turbine-side bearing 16A, and an outer peripheral end 43 of the bearing housing 42 and a flange portion 48 of the turbine housing 40 are fastened together by fastening members 49 such as bolts.

[0019] The casing 24 includes a partition 54 configured to separate the motor 4 (see FIG. 1) from the refrigerant flow path 22 of the turbine 8, and the partition 54 is provided with a heat insulating mechanism 56 for suppressing heat input from the motor 4 to the refrigerant flowing through the refrigerant flow path 22.

[0020] In the exemplary embodiment shown in FIG. 2 , the partition section 54 is formed by the bearing housing 42 and a portion 58 of the turbine housing 40 adjacent to the bearing housing 42 (more specifically, the portion 46 a of the scroll section 46 adjacent to the bearing housing 42 and the flange portion 48).

[0021] 2 , the cavity 60 and the heat insulating material 62 are each provided over a range from a position inside the fixed vanes 26 to a position outside the scroll flow path 32 in the radial direction. The type of heat insulating material 62 is not particularly limited, and may be, for example, urethane foam, polystyrene foam, polyisocyanurate foam, or aerogel.

[0022] In the exemplary embodiment shown in FIG. 2 , the bearing housing 42 includes an annular motor-side flow passage wall 64 that forms the flow passage wall surface 36 a on the motor 4 (see FIG. 1 ) side of the intermediate flow passage 36. The nozzle mount 44 includes an annular shroud-side flow passage wall 66 that forms the flow passage wall surface 36 b on the opposite side of the motor 4 in the intermediate flow passage 36, and an annular shroud wall 67 that connects to the inner peripheral end of the shroud-side flow passage wall 66 and faces the tips 30 a of the turbine blades 30 of the turbine wheel 18. In the illustrated example, the shroud-side flow passage wall 66 is formed in a flat plate shape along a plane perpendicular to the axial direction. The shroud wall 67 is formed in a cylindrical shape with its central axis coincident with the rotational axis of the turbine wheel 18.

[0023] 2 is fixed to the shroud-side flow passage wall 66. The stationary vane 26 is configured integrally with the shroud-side flow passage wall 66 by being welded to the shroud-side flow passage wall 66 or by being integrally molded therewith. In other words, the stationary vane 26 is configured integrally with the nozzle mount 44 by being welded to the nozzle mount 44 or by being integrally molded therewith.

[0024] According to the above-described electric turbo machine 2, the heat insulating mechanism 56 is provided in the partition 54, which suppresses heat input from the motor 4 to the refrigerant flowing through the refrigerant flow path 22 of the turbine 8, thereby improving the operating efficiency of the turbine 8. Furthermore, because the fixed vanes 26 are fixed to the shroud-side flow path wall 66, a decrease in the heat insulating performance of the heat insulating mechanism 56 due to the provision of a fixing member (e.g., a decrease in heat insulating performance due to the formation of a flow path through which the refrigerant flows between the intermediate flow path 36 and the cavity 60 by the space provided with the fixing member) can be suppressed compared to when the fixed vanes 26 are fixed to the motor-side flow path wall 64 (the partition 54 side) using a fixing member such as a fixing pin. Therefore, it is possible to realize an electric turbo machine 2 that has a high degree of freedom in designing the structure for fixing the fixed vanes 26 while suppressing a decrease in turbine performance. Furthermore, the fixed vanes 26 are configured integrally with the shroud side flow path wall 66 by being welded to the shroud side flow path wall 66 or by being integrally molded with the shroud side flow path wall 66. Therefore, compared to when the fixed vanes 26 are fixed to the motor side flow path wall 64 by welding or the like, the heat input from the motor 4 to the fixed vanes 26 via the motor side flow path wall 64 can be suppressed, and the operating efficiency of the turbine 8 can be improved.

[0025] FIG. 3 is a schematic partial cross-sectional view showing an example of a specific configuration of portion X in FIG. 2 . In some embodiments, as shown in FIG. 3 , the turbine 8 includes a fixing pin 68 (fixing member) for fixing the nozzle mount 44 to the turbine housing 40. The fixing pin 68 includes a shaft portion 68a and a head portion 68b having an outer diameter larger than that of the shaft portion 68a. The fixing pin 68 axially penetrates a shroud-side flowpath wall portion 66 of the nozzle mount 44 from the flowpath wall surface 36b side and is fixed to the nozzle mount support portion 50 of the turbine housing 40. A through-hole 69 is formed in the shroud-side flowpath wall portion 66 and penetrates the shroud-side flowpath wall portion 66 in the axial direction. The through-hole 69 includes a large hole portion 69a that accommodates the head portion 68b of the fixing pin 68 and a small hole portion 69b through which the shaft portion 68a passes and which has a smaller diameter than the large hole portion 69a. The large hole portion 69a and the small hole portion 69b are in axial communication with each other. An axially extending mating hole 70 that communicates with the through hole 69 is formed in the opposing surface 50a, which is the wall surface facing the nozzle mount 44 in the nozzle mount support portion 50 of the turbine housing 40, and the tip of the shaft portion 68a of the fixing pin 68 is pressed into the mating hole 70 and engages with the mating hole 70, thereby fixing the nozzle mount 44 to the turbine housing 40.

[0026] 3 , a through hole 69 in which a fixing pin 68 is provided is formed in the shroud-side flow path wall 66. Therefore, compared to when the fixing pin is fixed to the motor-side flow path wall 64, providing the fixing pin 68 does not form a flow path through which the coolant circulates between the intermediate flow path 36 and the cavity 60 (thermal insulation space). This makes it possible to realize an electric turbomachine 2 that has a high degree of freedom in designing the structure for fixing the fixed vanes 26 while suppressing a decrease in turbine performance. Furthermore, because the fixing pin 68 is provided in the shroud-side flow path wall 66 rather than the shroud wall 67, the risk of the fixing pin 68 coming into contact with the tip of the turbine blade 30 can be reduced.

[0027] FIG. 4 is a schematic partial cross-sectional view showing another example of the specific configuration of portion X in FIG. 2 . In some embodiments, as shown in FIG. 4 , the turbine 8 includes a fixing pin 71 (fixing member) for fixing the nozzle mount 44 to the turbine housing 40. The fixing pin 71 includes a shaft portion 71a and a head portion 71b having an outer diameter larger than that of the shaft portion 71a. The fixing pin 71 radially penetrates a shroud wall portion 67 of the nozzle mount 44 from the wheel flow path 34 side and is fixed to the nozzle mount support portion 50 of the turbine housing 40. A through hole 72 is formed in the shroud wall portion 67 and penetrates the shroud wall portion 67 in the radial direction. The through hole 72 includes a large hole portion 72a that accommodates the head portion 71b of the fixing pin 71 and a small hole portion 72b through which the shaft portion 71a passes and which has a smaller hole diameter than the large hole portion 72a, and the large hole portion 72a and the small hole portion 72b are radially connected to each other. The nozzle mount support portion 50 of the turbine housing 40 has a mating hole 73 formed therein that extends radially and communicates with the through hole 72, and the tip of the shaft portion 71a of the fixing pin 71 is pressed into the mating hole 73 and engages with the mating hole 73, thereby fixing the nozzle mount 44 to the turbine housing 40.

[0028] According to the configuration shown in FIG. 4 , even if the fixing pin 71 is provided, a flow path through which the refrigerant flows is not formed between the intermediate flow path 36 and the hollow portion 60 (insulated space). Therefore, it is possible to realize an electric turbomachine 2 that has a high degree of freedom in designing the structure for fixing the fixed vanes 26 while suppressing a decrease in turbine performance.

[0029] Figure 5 is a schematic partial cross-sectional view showing yet another example of the specific configuration of portion X in Figure 2. In some embodiments, as shown in Figure 5, for example, the shroud-side flow path wall 66 includes a first wall surface 45 that faces away from the motor-side flow path wall 64 and faces the turbine housing 40, and a first groove 75 extending along the circumferential direction is formed in the first wall surface 45. Furthermore, a second groove 76 extending along the circumferential direction is formed in the outer peripheral surface 67a of the shroud wall 67. In the embodiment shown in Figure 5, the turbine 8 includes a first elastic member 77 accommodated in the first groove 75 and abutting against the turbine housing 40 in the axial direction, and a second elastic member 78 accommodated in the second groove 76 and abutting against the turbine housing 40 in the radial direction.

[0030] In this case, as shown in FIG. 6 , for example, one of the nozzle mount support portion 50 of the turbine housing 40 and the nozzle mount 44 (the nozzle mount support portion 50 in the illustrated example) may be provided with a rotation stop pin 79 that functions as a rotation stop to prevent rotation of the nozzle mount 44 in the circumferential direction, and the other of the nozzle mount support portion 50 of the turbine housing 40 and the nozzle mount 44 (the nozzle mount 44 in the illustrated example) may be formed with a pin hole 80 into which the rotation stop pin 79 is inserted. Furthermore, each of the first elastic member 77 and the second elastic member 78 may be, for example, an O-ring. Each of the rotation stop pin 79 and the pin hole 80 may be provided at one location in the circumferential direction or at multiple locations in the circumferential direction.

[0031] 5 and 6, the nozzle mount 44 can be fixed to the turbine housing 40 by utilizing the repulsive forces of the first elastic member 77 and the second elastic member 78. Furthermore, because a flow path through which the refrigerant flows is not formed between the intermediate flow passage 36 and the cavity 60 (thermal insulation space), it is possible to realize an electric turbomachine 2 that has a high degree of freedom in designing the structure for fixing the fixed vanes 26 while suppressing a decrease in turbine performance. Furthermore, with the configuration shown in Fig. 6, the anti-rotation pin 79 abuts against the inner circumferential surface of the pin hole 80, thereby preventing the nozzle mount 44 from rotating in the circumferential direction.

[0032] Fig. 7 is a schematic cross-sectional view showing another example of a cross section along the axial direction of the turbine 8 of the electric turbo machine 2 shown in Fig. 1. In the electric turbo machine 2 shown in Fig. 7, the same reference numerals as those of the electric turbo machine 2 shown in Fig. 2 and the like indicate the same components as those of the electric turbo machine 2 shown in Fig. 2 and the like unless otherwise specified, and redundant explanations will be omitted.

[0033] In the electric turbo machine 2 shown in FIG. 2 , the nozzle mount 44 and the turbine housing 40 are configured as separate parts. However, the electric turbo machine 2 shown in FIG. 7 does not have a nozzle mount 44, and the shroud-side flow path wall portion 66 that forms the flow path wall surface 36 b on the opposite side of the motor 4 in the intermediate flow path 36 is configured by the turbine housing 40.

[0034] 7 , the stationary vane 26 may be welded to the turbine housing 40 or may be integrally molded with the turbine housing 40. When the stationary vane 26 is welded to the turbine housing 40, the end of the stationary vane 26 opposite the motor 4 in the axial direction is welded to a flow passage wall surface 36b of the intermediate flow passage 36 opposite the motor 4, thereby fixing the stationary vane 26 to the shroud-side flow passage wall portion 66 of the turbine housing 40. When the stationary vane 26 and the turbine housing 40 are integrally molded, the stationary vane 26 and the turbine housing 40 may be molded as a single component by, for example, metal additive manufacturing or the like.

[0035] 7 , there is no need to provide a nozzle mount as a separate part from the turbine housing 40, and there is no need to provide a fixing pin for fixing the nozzle mount to the turbine housing 40. This reduces the number of parts in the electric turbo machine 2. Furthermore, the fixed vanes 26 are integrally configured with the shroud-side flowpath wall 66 by being welded to the shroud-side flowpath wall 66 or by being integrally molded therewith. This reduces heat input from the motor 4 to the fixed vanes 26 via the motor-side flowpath wall 64, compared to when the fixed vanes 26 are fixed to the motor-side flowpath wall 64 by welding or the like, thereby improving the operating efficiency of the turbine 8. Furthermore, when the fixed vanes 26 and the turbine housing 40 are integrally molded by metal additive manufacturing or the like, welding work is not required, and alignment work between the fixed vanes 26 and the turbine housing 40 is also not required, compared to when the fixed vanes 26 are welded to the turbine housing 40.

[0036] Fig. 8 is a schematic cross-sectional view showing yet another example of a cross section along the axial direction of the turbine 8 of the electric turbo machine 2 shown in Fig. 1. In the electric turbo machine 2 shown in Fig. 8, the same reference numerals as those of the electric turbo machine 2 shown in Fig. 2 and the like indicate the same components as those of the electric turbo machine 2 shown in Fig. 2 and the like, unless otherwise specified, and redundant explanations will be omitted.

[0037] In the electric turbomachine 2 shown in FIG. 2 , the nozzle mount 44 includes the annular shroud-side flowpath wall portion 66 and the cylindrical shroud wall portion 67 that protrudes in the axial direction from the shroud-side flowpath wall portion 66. However, in some embodiments, as shown in FIG. 8 , the nozzle mount 44 may not include the cylindrical shroud wall portion 67 that protrudes in the axial direction from the shroud-side flowpath wall portion 66.

[0038] 8 , the turbine 8 includes a fixing pin 81 (fixing member) for fixing the nozzle mount 44 to the turbine housing 40. The fixing pin 81 includes a shaft portion 81 a and a head portion 81 b having an outer diameter larger than the outer diameter of the shaft portion 81 a. The fixing pin 81 axially passes through the nozzle mount support portion 50, which supports the nozzle mount 44 in the turbine housing 40, from the side opposite the nozzle mount 44, and is fixed to the nozzle mount 44.

[0039] The nozzle mount 44 includes a first wall surface 45 that faces away from the motor-side flowpath wall portion 64 and faces the turbine housing 40. A through-hole 82 that penetrates the nozzle mount support portion 50 in the axial direction is formed in a portion 51 adjacent to the first wall surface 45. The through-hole 82 includes a large hole portion 82a that accommodates the head 81b of the fixing pin 81 and a small hole portion 82b through which the shaft portion 81a passes and has a smaller diameter than the large hole portion 82a, with the large hole portion 82a and the small hole portion 82b communicating in the axial direction. A fitting hole 83 that extends in the axial direction and communicates with the through-hole 82 is formed in the first wall surface 45 of the nozzle mount 44. The fixing pin 81 penetrates the through-hole 82, and the tip of the shaft portion 81a of the fixing pin 81 is press-fitted into the fitting hole 83, thereby fixing the nozzle mount 44 to the turbine housing 40.

[0040] Compared to the configuration shown in Figure 3, the configuration shown in Figure 8 does not require the fixed pin 81 to pass through the space between circumferentially adjacent fixed vanes 26, so the nozzle mount 44 can be easily fixed to the turbine housing 40 even if the circumferential pitch of the multiple fixed vanes 26 is small.

[0041] Figure 9 is a schematic cross-sectional view for explaining a modified example of the electric turbo machine 2 shown in Figure 8. Figure 10 is a diagram showing the arrangement of the fixed vanes 26 and the like in the electric turbo machine 2 shown in Figure 9 as viewed in the axial direction. In the electric turbo machine 2 shown in Figures 9 and 10, reference numerals that are common to each component of the electric turbo machine 2 shown in Figure 8 and the like indicate the same components as the electric turbo machine 2 shown in Figure 8 and the like, unless otherwise specified, and duplicated explanations will be omitted.

[0042] The electric turbo machine 2 shown in FIGS. 9 and 10 includes a fixing pin 84 that penetrates the fixed vane 26 for each fixed vane 26, instead of the fixing pin 81 shown in FIG.

[0043] 9 and 10 , the fixed pin 84 includes a shaft portion 84a and a head portion 84b having an outer diameter larger than that of the shaft portion 84a. The fixed pin 84 axially penetrates the fixed vane 26 and the nozzle mount 44 and is fixed to the nozzle mount support portion 50 of the turbine housing 40. A through hole 85 is formed in the fixed vane 26 and extends therethrough in the axial direction. The through hole 85 includes a large hole portion 85a that accommodates the head portion 84b of the fixed pin 84, and a small hole portion 85b through which the shaft portion 84a passes and which has a smaller diameter than the large hole portion 85a. The large hole portion 85a and the small hole portion 85b are in axial communication with each other. The nozzle mount 44 is also formed with a through hole 86 that penetrates therethrough in the axial direction and is in communication with the through hole 85. An axially extending fitting hole 87 that communicates with the through hole 86 is formed in the opposing surface 50a, which is the wall surface of the turbine housing 40 that faces the first wall surface 45 of the nozzle mount 44. The fixing pin 84 passes through the through hole 85 of the fixed vane 26 and the through hole 86 of the nozzle mount 44, and the tip of the shaft portion 84a of the fixing pin 84 is press-fitted into the fitting hole 87 to fix the nozzle mount 44 to the turbine housing 40.

[0044] According to the configuration shown in Figures 9 and 10, compared to the configuration shown in Figure 3, there is no need to pass the fixing pin 84 through the space between circumferentially adjacent fixed vanes 26, so the nozzle mount 44 can be easily fixed to the turbine housing 40 even if the pitch between the multiple fixed vanes 26 in the circumferential direction is small.

[0045] Fig. 11 is a schematic cross-sectional view for explaining a modified example of the electric turbo machine 2 shown in Fig. 3. In the electric turbo machine 2 shown in Fig. 11, reference numerals that are common to the components of the electric turbo machine 2 shown in Fig. 3 and the like indicate the same components as the components of the electric turbo machine 2 shown in Fig. 3 and the like, unless otherwise specified, and duplicated explanations will be omitted.

[0046] In some embodiments, as shown in FIG. 11 , the flow path width W1 of the intermediate flow path 36 in the axial direction at the position of the leading edge 26 a of the fixed vane 26 is greater than the flow path width W2 of the intermediate flow path 36 in the axial direction at the position of the trailing edge 26 b of the fixed vane 26.

[0047] 11 , the flow passage wall surface 36b of the intermediate flow passage 36 opposite the motor 4 is inclined with respect to the radial direction. Here, if a plane that passes through position P1 where the trailing edge 26b of the fixed vane 26 and the motor-side flow passage wall portion 64 (flow passage wall surface 36b) connect and is perpendicular to the axial direction is defined as a first plane H1, the axial distance d1 between the flow passage wall surface 36b of the intermediate flow passage 36 opposite the motor 4 (see FIG. 1) and the first plane H1 increases radially outward. Furthermore, the fixing pin 68, the through hole 69, and the fitting hole 70 each extend in a direction inclined with respect to the axial direction so as to move radially inward with increasing distance from the first plane H1.

[0048] 11 , the refrigerant flow velocity at the leading edge 26 a of the fixed vane 26 is made slower than the refrigerant flow velocity at the trailing edge 26 b, thereby suppressing refrigerant flow separation on the blade surface of the fixed vane 26 and improving turbine performance. In addition, the refrigerant flow F1 (main stream) at the trailing edge 26 b of the fixed vane 26 is shifted toward the hub 28 of the turbine wheel 18, thereby reducing leakage loss at the tip side of the turbine blades 30.

[0049] Fig. 12 is a schematic cross-sectional view for explaining a modified example of the electric turbo machine 2 shown in Fig. 11. In the electric turbo machine 2 shown in Fig. 12, the same reference numerals as those of the electric turbo machine 2 shown in Fig. 11 and the like indicate the same components as those of the electric turbo machine 2 shown in Fig. 3 and the like, unless otherwise specified, and redundant explanations will be omitted.

[0050] In the embodiment shown in Figure 12, the flow path width W1 of the intermediate flow path 36 in the axial direction at the position of the leading edge 26a of the fixed vane 26 is larger than the flow path width W2 of the intermediate flow path 36 in the axial direction at the position of the trailing edge 26b of the fixed vane 26, but in the embodiment shown in Figure 12, the flow path wall surface 36a, rather than the flow path wall surface 36b, is inclined relative to the radial direction.

[0051] In the embodiment shown in Figure 12, if the plane that passes through the position P1 where the trailing edge 26b of the fixed vane 26 and the motor side flow path wall portion 64 (flow path wall surface 36b) connect and is perpendicular to the axial direction is defined as the first plane H1, the axial distance d2 between the flow path wall surface 36a on the motor 4 (see Figure 1) side in the intermediate flow path 36 and the first plane H1 becomes larger as it moves radially outward.

[0052] 12 , the coolant flow velocity at the leading edge 26 a of the fixed vane 26 is made smaller than the coolant flow velocity at the trailing edge 26 b, thereby suppressing coolant flow separation on the blade surface of the fixed vane 26 and improving turbine performance. In addition, because the flow path wall surface 36 b on the side opposite the motor 4 in the intermediate flow path 36 can be formed along a plane perpendicular to the axial direction, processing when fixing the fixed vane 26 with the fixing pin 68 (for example, processing to form a through hole 69 in the nozzle mount 44 for passing the fixing pin 68 therethrough) can be simplified.

[0053] Fig. 13 is a schematic cross-sectional view for explaining another modified example of the electric turbo machine 2 shown in Fig. 3. In the electric turbo machine 2 shown in Fig. 13, the same reference numerals as those of the components of the electric turbo machine 2 shown in Fig. 2 and Fig. 3 indicate the same components as those of the electric turbo machine 2 shown in Fig. 2 and Fig. 3 unless otherwise specified, and duplicated explanations will be omitted.

[0054] In the electric turbomachine 2 shown in Fig. 3 , the nozzle mount 44 includes an annular shroud-side flowpath wall 66 and a cylindrical shroud wall 67 that protrudes in the axial direction from the shroud-side flowpath wall 66. However, in some embodiments, as shown in Fig. 13 , the nozzle mount 44 may not include the cylindrical shroud wall 67 that protrudes in the axial direction from the shroud-side flowpath wall 66. In the embodiment shown in Fig. 13 , the turbine housing 40 includes an opposing surface 50a that faces the first wall surface 45 (the wall surface facing the opposite side from the motor-side flowpath wall 64) of the nozzle mount 44, and a protrusion 53 that is located radially inward of the opposing surface 50a and protrudes from the opposing surface 50a toward the intermediate flowpath 36 in the axial direction, and the protrusion 53 is located radially inward of the nozzle mount 44.

[0055] Here, if the flow passages formed between the multiple fixed vanes 26 in the circumferential direction are defined as nozzle flow passages 36c, the casing 24 includes a bypass flow passage 90 that supplies the refrigerant flowing through the scroll flow passage 32 to a position midway along the nozzle flow passage 36c (the position of the outlet 90b of the bypass flow passage 90 in FIG. 13 ) bypassing the inlet 36i of the nozzle flow passage 36c.

[0056] The bypass flow path 90 includes a first flow path portion 91 including an inlet 90a of the bypass flow path 90 and a second flow path portion 92 including an outlet 90b of the bypass flow path 90. The nozzle mount 44 includes a first wall surface 45 that faces away from the motor-side flow path wall portion 64 and faces the turbine housing 40, and the turbine housing 40 includes an opposing surface 50a that is a wall surface that faces the first wall surface 45. In the illustrated cross section, a first gap g1 extending along the radial direction is formed between the first wall surface 45 of the nozzle mount 44 and the opposing surface 50a of the turbine housing 40, and the first gap g1 constitutes the first flow path portion 91. In other words, the inlet 90a and the first flow path portion 91 of the bypass flow path 90 are defined by the first wall surface 45 of the nozzle mount 44 and the opposing surface 50a of the turbine housing 40.

[0057] The protrusion 53 of the turbine housing 40 includes an opposing surface 50b, which is a wall surface that faces an inner circumferential surface 93 of the nozzle mount 44. The inner circumferential surface 93 of the nozzle mount 44 faces radially inward, and the opposing surface 50b faces radially outward. In the cross section shown, a second gap g2 extending along the axial direction is formed between the inner circumferential surface 93 of the nozzle mount 44 and the opposing surface 50b of the turbine housing 40, and the second gap g2 constitutes the second flow path portion 92. In other words, the outlet 90b of the bypass flow path 90 and the second flow path portion 92 are defined by the inner circumferential surface 93 of the nozzle mount 44 and the opposing surface 50b of the turbine housing 40.

[0058] In the configuration shown in FIG. 13 , a portion of the refrigerant flowing through the scroll flow path 32 is supplied to the nozzle flow path 36 c by passing through the first flow path section 91 and the second flow path section 92 in that order, thereby bypassing the inlet 36 i of the nozzle flow path 36 c and being supplied to a position midway through the nozzle flow path 36 c.

[0059] In a low-temperature environment of a chiller (e.g., an environment where the turbine inlet temperature is approximately −70°C and the turbine outlet temperature is −90°C or lower), there is a risk that ice formed in narrow passages, such as the outlet of the nozzle passage 36c, will grow and cause blockage of the nozzle passage 36c. In this regard, in the electric turbo machine 2 shown in FIG. 13 , high-pressure refrigerant flowing through the scroll passage 32 passes through the bypass passage 90 and is supplied as a jet F2 (see FIG. 14 ) to a position midway through the nozzle passage 36c. Therefore, even if ice forms near the outlet of the nozzle passage 36c, the jet from the bypass passage 90 can push the ice out of the nozzle passage 36c, thereby suppressing ice growth in the nozzle passage 36c. Therefore, blockage of the nozzle passage 36c due to ice formation can be suppressed. Furthermore, by utilizing the first gap g1, which is the gap between the first wall surface 45 of the nozzle mount 44 and the opposing surface 50a of the turbine housing 40, as part of the bypass passage 90, ice formation in the nozzle passage 36c can be suppressed with a simple configuration. In addition, by utilizing the second gap g2, which is the gap between the inner surface 93 of the nozzle mount 44 and the opposing surface 50b of the turbine housing 40, as part of the bypass flow path 90, icing in the nozzle flow path 36c can be suppressed with a simple configuration.

[0060] Fig. 15 is a schematic cross-sectional view for explaining a modified example of the electric turbo machine 2 shown in Fig. 13. In the electric turbo machine 2 shown in Fig. 15, reference numerals that are common to the components of the electric turbo machine 2 shown in Fig. 13 indicate the same components as the components of the electric turbo machine 2 shown in Fig. 13 unless otherwise specified, and duplicated explanations will be omitted.

[0061] 15 , the size of the first gap g1 in the axial direction increases toward the inlet 90a of the bypass flow passage 90. That is, the axial distance between the first wall surface 45 of the nozzle mount 44 and the opposing surface 50a of the turbine housing 40 may increase toward the inlet 90a of the bypass flow passage 90 (toward the outside in the radial direction).

[0062] According to the configuration shown in FIG. 15, the refrigerant flowing through the scroll passage 32 can be guided to the bypass passage 90, thereby enhancing the effect of suppressing icing in the nozzle passage 36c.

[0063] Figure 16 is a schematic cross-sectional view for explaining another modified example of the electric turbo machine 2 shown in Figure 13. Figure 17 is a diagram showing an example of the positional relationship between the fixed vane 26 and the outlet 90b of the bypass flow path 90 when viewed in the axial direction in the electric turbo machine 2 shown in Figure 16. In the electric turbo machine 2 shown in Figures 16 and 17, reference numerals that are common to each component of the electric turbo machine 2 shown in Figure 13 indicate the same components as the electric turbo machine 2 shown in Figure 13 unless otherwise specified, and duplicated explanations will be omitted.

[0064] In some embodiments, the size of the second gap g2 in the radial direction may vary depending on the position in the circumferential direction, as shown in Figures 16 and 17. In the embodiments shown in Figures 16 and 17, the second gap g2 includes a constant gap portion gc, where the size of the second gap g2 in the radial direction is constant regardless of the position in the circumferential direction, and a large gap portion gd connected to the constant gap portion gc, and the size of the large gap portion gd in the radial direction is larger than the size of the constant gap portion gc in the radial direction. In the illustrated exemplary embodiment, the large gap portion gd is formed in a circular shape when viewed in the axial direction.

[0065] Here, as shown in Figure 17, of the multiple fixed vanes 26 of the turbine 8, two adjacent fixed vanes 26 sandwiching the large gap portion gd are defined as the downstream fixed vane 26D, and the fixed vane 26 upstream of the large gap portion gd is defined as the upstream fixed vane 26U.

[0066] In the embodiment shown in FIG. 17, the distance dp between the suction side 26Dp of the downstream fixed vane 26D and the large gap gd is equal to the distance ds between the pressure side 26Us of the upstream fixed vane 26U and the large gap gd.

[0067] In the embodiment shown in Figure 17, at least a portion of the outlet 90b of the bypass flow path 90 (large gap portion gd in the illustrated example) is located at the throat position P0 where the flow path width W in the nozzle flow path 36c is minimum.

[0068] 16 and 17, ice can be pushed out of the nozzle flow path 36c by the jet flow from the bypass flow path 90, thereby suppressing the growth of ice in the nozzle flow path 36c. Furthermore, by locating at least a portion of the outlet 90b of the bypass flow path 90 at the throat position P0 where icing is likely to occur in the nozzle flow path 36c, icing in the nozzle flow path 36c can be effectively suppressed.

[0069] FIG. 18 is a diagram showing another example of the positional relationship between the fixed vane 26 and the outlet 90b of the bypass flow passage 90 when viewed in the axial direction in the electric turbomachine 2 shown in FIG.

[0070] 18 , the size of the second gap g2 in the radial direction varies depending on the circumferential position. The second gap g2 includes a constant gap portion gc, where the size of the second gap g2 in the radial direction is constant regardless of the circumferential position, and a large gap portion gd connected to the constant gap portion gc, and the size of the large gap portion gd in the radial direction is larger than the size of the constant gap portion gc in the radial direction. In the illustrated exemplary embodiment, the large gap portion gd is formed in a circular shape when viewed in the axial direction, and the size of the second gap g2 in the radial direction is largest at the large gap portion gd.

[0071] In the embodiment shown in FIG. 18, the distance dp between the suction side 26Dp of the downstream fixed vane 26D and the large gap gd is smaller than the distance ds between the pressure side 26Us of the upstream fixed vane 26U and the large gap gd.

[0072] If ice forms on the suction side of the fixed vane 26, the throat of the nozzle flow path 36c is likely to narrow, which will have a significant impact on turbine performance. Therefore, as shown in Figure 18, by making the distance dp between the suction side 26Dp of the downstream fixed vane 26D and the large gap gd smaller than the distance ds between the ventral side 26Us of the upstream fixed vane 26U and the large gap gd, ice formation near the suction side 26Dp of the downstream fixed vane 26D can be effectively suppressed.

[0073] The present disclosure is not limited to the above-described embodiments, but also includes modifications to the above-described embodiments and appropriate combinations of these modifications.

[0074] For example, while the bypass flow passage 90 described with reference to Figures 13 to 18 was formed by the gap between the nozzle mount 44 and the turbine housing 40, the bypass flow passage 90 may be formed to pass through the motor-side flow passage wall 64, as shown in Figure 19, for example. In the exemplary embodiment shown in Figure 19, an axial hole 94 is formed in the motor-side flow passage wall 64, extending in the axial direction from the flow passage wall surface 36a on the motor 4 side of the intermediate flow passage 36 to the cavity 60, and the bypass flow passage 90 is formed by the gap 95 between the scroll section 46 and the motor-side flow passage wall 64, a part of the cavity 60, and the axial hole 94. However, in the configuration shown in Figure 19, the refrigerant flowing through the bypass flow passage 90 is heated by heat input from the motor 4, and therefore the configurations shown in Figures 13 to 18 are preferable from the standpoint of turbine efficiency.

[0075] Furthermore, in each of the embodiments described using Figures 2 to 18, the heat insulation mechanism 56 was composed of a hollow portion 60 provided inside the partition portion 54 and a heat insulating material 62 provided in the hollow portion 60, but the heat insulation mechanism 56 does not have to include the heat insulating material 62. For example, by including a hollow portion 60 as shown in Figure 19, it is possible to suppress heat input from the motor 4 to the refrigerant flowing through the refrigerant flow path 22.

[0076] Furthermore, while the bypass flow passage 90 described with reference to FIGS. 13 to 18 is formed by a gap between the nozzle mount 44 and the turbine housing 40, as shown in FIG. 20 , at least a portion of the bypass flow passage 90 may be formed inside the nozzle mount 44. In the exemplary embodiment shown in FIG. 20 , the nozzle mount 44 includes an inclined hole 96 penetrating the nozzle mount 44 from the flow passage wall surface 36 b to the first wall surface 45. The inclined hole 96 extends in a direction inclined with respect to the axial direction so as to extend radially inward as it approaches the flow passage wall surface 36 b. The bypass flow passage 90 is also formed by the inclined hole 96 and a portion of the first gap g1 between the first wall surface 45 of the nozzle mount 44 and the opposing surface 50 a of the turbine housing 40. The configuration shown in FIG. 20 also allows the jet flow from the bypass flow passage 90 to push ice out of the nozzle flow passage 36 c, thereby suppressing ice growth in the nozzle flow passage 36 c.

[0077] The contents described in each of the above embodiments can be understood, for example, as follows.

[0078] [1] An electric turbo machine according to at least one embodiment of the present disclosure is an electric turbo machine for a refrigerator (for example, the electric turbo machine 2 described above), comprising: a motor (for example, the motor 4 described above); and a turbine (for example, the turbine 8 described above) connected to the motor via a rotating shaft (for example, the rotating shaft 6A described above), wherein the turbine includes: a turbine wheel (for example, the turbine wheel 18 described above); a casing (for example, the casing 24 described above) that houses the turbine wheel and forms a refrigerant flow path (for example, the refrigerant flow path 22 described above) through which a refrigerant flows; and a fixed vane (for example, the fixed vane 26 described above) that is provided upstream of the turbine wheel in the refrigerant flow path, wherein the casing includes a partition (for example, the partition 54 described above) that separates the motor from the refrigerant flow path of the turbine, and the partition is provided with a heat insulating mechanism (for example, the heat insulating mechanism 56 described above) for suppressing heat input from the motor to the refrigerant flowing through the refrigerant flow path, The refrigerant flow path includes a scroll flow path (for example, the above-mentioned scroll flow path 32) provided on the outer periphery of the turbine wheel, and an intermediate flow path (for example, the above-mentioned intermediate flow path 36) provided between the scroll flow path and the turbine wheel, the casing includes a motor-side flow path wall portion (for example, the above-mentioned motor-side flow path wall portion 64) that forms the flow path wall surface (for example, the above-mentioned flow path wall surface 36a) on the motor side of the intermediate flow path, and a shroud-side flow path wall portion (for example, the above-mentioned shroud-side flow path wall portion 66) that forms the flow path wall surface (for example, the above-mentioned flow path wall surface 36b) on the opposite side of the motor in the intermediate flow path, and the fixed vane is fixed to the shroud-side flow path wall portion.

[0079] According to the electric turbomachine described in [1] above, since the partition section is provided with a heat insulating mechanism, heat input from the motor to the coolant flowing through the coolant flow passage of the turbine can be suppressed, thereby improving the operating efficiency of the turbine. Furthermore, since the fixed vanes are fixed to the shroud-side passage wall section, a deterioration in the heat insulating performance of the heat insulating mechanism due to the provision of a fixing member (e.g., a deterioration in heat insulating performance due to the coolant flowing between the intermediate passage and the heat insulating mechanism through a space provided with the fixing member) can be suppressed compared to when, for example, the fixed vanes are fixed to the motor-side passage wall section (the partition section side) using a fixing member such as a fixing pin. Therefore, it is possible to realize an electric turbomachine that has a high degree of freedom in designing the structure for fixing the fixed vanes while suppressing a deterioration in turbine performance.

[0080] [2] In some embodiments, in the electric turbomachine described in [1] above, the casing includes a turbine housing (e.g., the above-mentioned turbine housing 40) that houses the turbine wheel and forms at least a part of the scroll flow path, and a nozzle mount (e.g., the above-mentioned nozzle mount 44) that forms the shroud-side flow path wall portion, the fixed vane is configured integrally with the nozzle mount by being welded to the nozzle mount or by being integrally molded with the nozzle mount, and the turbine includes fixing members (e.g., the above-mentioned fixing pin 68, fixing pin 71, first elastic member 77, second elastic member 78, fixing pin 81, fixing pin 84) for fixing the nozzle mount to the turbine housing.

[0081] According to the electric turbomachine described in the above [2], it is possible to realize an electric turbomachine with a high degree of freedom in designing the structure for fixing the fixed vanes while suppressing a decrease in turbine performance.

[0082] [3] In some embodiments, in the electric turbomachine described in [2] above, the fixing member is fixed to the turbine housing by passing through a through hole (e.g., the above-mentioned through hole 69 or through hole 86) formed in the shroud-side flow path wall portion.

[0083] According to the electric turbomachine described in [3] above, it is possible to realize an electric turbomachine with a high degree of freedom in designing the structure for fixing the fixed vanes while suppressing a decrease in turbine performance. Furthermore, compared to the electric turbomachine described in [4] below, it is possible to reduce the risk of the fixed members coming into contact with the tips of the turbine blades.

[0084] [4] In some embodiments, in the electric turbomachine described in [2] above, the nozzle mount includes an annular shroud wall portion (e.g., the above-mentioned shroud wall portion 67) that is connected to the shroud-side flow path wall portion and faces a tip (e.g., the above-mentioned tip 30a) of a turbine blade (e.g., the above-mentioned turbine blade 30) of the turbine wheel, and the fixing member is fixed to the turbine housing by passing through a through hole (e.g., the above-mentioned through hole 72) formed in the shroud wall portion.

[0085] According to the electric turbomachine described in [4] above, it is possible to realize an electric turbomachine with a high degree of freedom in designing the structure for fixing the fixed vanes while suppressing a decrease in turbine performance.

[0086] [5] In some embodiments, in the electric turbomachine described in [2] above, the nozzle mount includes a shroud wall portion (e.g., the above-mentioned shroud wall portion 67) that is connected to the shroud-side flowpath wall portion and faces a tip (e.g., the above-mentioned tip 30a) of a turbine blade (e.g., the above-mentioned turbine blade 30) of the turbine wheel, the shroud-side flowpath wall portion includes a first wall surface (e.g., the above-mentioned first wall surface 45) that faces opposite to the motor-side flowpath wall portion and faces the turbine housing, a first groove (e.g., the above-mentioned first groove 75) that extends along a circumferential direction of the electric turbomachine is formed in the first wall surface, and a second groove (e.g., the above-mentioned second groove 76) that extends along the circumferential direction is formed in an outer peripheral surface of the shroud wall portion, and the turbine includes a first elastic member (e.g., the above-mentioned first elastic member 77) that is accommodated in the first groove and abuts against the turbine housing, and a second elastic member (e.g., the above-mentioned second elastic member 78) that is accommodated in the second groove and abuts against the turbine housing.

[0087] According to the electric turbomachine described in [5] above, the nozzle mount can be fixed to the turbine housing by utilizing the repulsive forces of the first elastic member and the second elastic member.

[0088] [6] In some embodiments, in the electric turbomachine described in any of [1] to [5] above, the casing includes a turbine housing (e.g., the above-mentioned turbine housing 40) that houses the turbine wheel and forms at least a part of the scroll flow passage, and the fixed vanes are welded to the turbine housing or integrally formed with the turbine housing.

[0089] According to the electric turbomachine described in [6] above, there is no need to provide a nozzle mount that is a separate part from the turbine housing, and there is also no need to provide a fixing pin for fixing the nozzle mount to the turbine housing. This allows the number of parts in the electric turbomachine to be reduced. Furthermore, when the fixed vane and the turbine housing are integrally molded, welding work is not required, as compared to when the fixed vane is welded to the turbine housing, and alignment work between the fixed vane and the turbine housing is also not required.

[0090] [7] In some embodiments, in the electric turbomachine described in [2] above, the fixing member is a fixing pin (e.g., the fixing pin 81 described above) including a shaft portion (e.g., the shaft portion 81a described above) and a head portion (e.g., the head portion 81b described above) having an outer diameter larger than that of the shaft portion, the nozzle mount includes a first wall surface (e.g., the first wall surface 45 described above) facing away from the motor-side flow path wall portion and facing the turbine housing, a through hole (e.g., the through hole 82 described above) is formed in a portion (e.g., portion 51) adjacent to the first wall surface in the turbine housing, a first hole (e.g., the fitting hole 83 described above) communicating with the through hole is formed in the first wall surface, and the fixing pin passes through the through hole, and the shaft portion of the fixing pin fits into the first hole in the first wall surface.

[0091] According to the electric turbomachine described in [7] above, compared to when the fixing member is passed through the nozzle mount from the intermediate flow path side (for example, in the case of [3] above), there is no need to pass the fixing member through the space between circumferentially adjacent fixed vanes, so the nozzle mount can be easily fixed to the turbine housing even when the circumferential pitch of multiple fixed vanes is small.

[0092] [8] In some embodiments, in the electric turbomachine described in [2] above, the fixing member is a fixing pin (e.g., the fixing pin 84 described above) including a shaft portion (e.g., the shaft portion 84a described above) and a head portion (e.g., the head portion 84b described above) having an outer diameter larger than that of the shaft portion, the fixing vane has a first through hole (e.g., the through hole 85 described above) formed therein that penetrates in the axial direction of the electric turbomachine, the nozzle mount has a second through hole (e.g., the through hole 86 described above) that communicates with the first through hole, and the turbine housing has an opposing surface (e.g., the opposing surface 50a described above) that faces the nozzle mount and a first hole (e.g., the fitting hole 87 described above) that communicates with the second through hole, and the fixing pin passes through the first through hole of the fixing vane and the second through hole of the nozzle mount, and the shaft portion of the fixing pin fits into the first hole of the turbine housing.

[0093] According to the electric turbomachine described in [8] above, compared to when the fixing member is passed through the nozzle mount from the intermediate flow path side (for example, in the case of [3] above), there is no need to pass the fixing member through the space between circumferentially adjacent fixed vanes, so the nozzle mount can be easily fixed to the turbine housing even when the circumferential pitch of multiple fixed vanes is small.

[0094] [9] In some embodiments, in the electric turbomachine described in any of [1] to [8] above, the flow path width (e.g., the above-mentioned flow path width W1) of the intermediate flow path in the axial direction of the electric turbomachine at the position of the leading edge of the fixed vane (e.g., the above-mentioned leading edge 26a) is larger than the flow path width (e.g., the above-mentioned flow path width W2) of the intermediate flow path in the axial direction at the position of the trailing edge of the fixed vane (e.g., the above-mentioned trailing edge 26b).

[0095] According to the electric turbomachine described in [9] above, the coolant flow velocity at the leading edge of the fixed vane can be made smaller than the coolant flow velocity at the trailing edge, thereby suppressing separation of the coolant flow on the vane surface and improving turbine performance.

[0096]

[10] In some embodiments, in the electric turbomachine described in [9] above, if a plane that passes through the position where the trailing edge of the fixed vane and the motor-side flow path wall portion are connected (for example, the above-mentioned position P1) and is perpendicular to the axial direction of the electric turbomachine is defined as a first plane (for example, the above-mentioned first plane H1), the axial distance (for example, the above-mentioned distance d1) between the flow path wall surface on the opposite side to the motor in the intermediate flow path and the first plane becomes larger toward the radial outside of the electric turbomachine.

[0097] According to the electric turbomachine described in

[10] above, the flow (main flow) of the refrigerant at the trailing edge of the fixed vane is closer to the hub of the turbine wheel, so that leakage loss at the tip side of the turbine blade can be reduced.

[0098]

[11] In some embodiments, in the electric turbomachine described in [9] or

[10] above, if a plane that passes through a position where the trailing edge of the fixed vane and the motor side flow path wall portion are connected (for example, the above-mentioned position P1) and is perpendicular to the axial direction of the electric turbomachine is defined as a first plane (for example, the above-mentioned first plane H1), the axial distance (for example, the above-mentioned distance d2) between the motor side flow path wall surface in the intermediate flow path and the first plane becomes larger toward the radial outside of the electric turbomachine.

[0099] According to the electric turbomachine described in

[11] above, the flow path wall surface on the opposite side of the intermediate flow path from the motor (for example, the above-mentioned flow path wall surface 36b) can be formed along a plane perpendicular to the axial direction, which makes it easier to process the fixed vane when fixing it with a fixing pin (for example, to process a through hole in the nozzle mount to pass the fixing pin through).

[0100]

[12] In some embodiments, in the electric turbomachine described in any of [1] to [5] and [7] to

[11] above, the turbine includes a plurality of the fixed vanes arranged in the intermediate flow passage at intervals in the circumferential direction of the electric turbomachine, and when a flow passage formed between the plurality of fixed vanes in the circumferential direction is defined as a nozzle flow passage (for example, the above-mentioned nozzle flow passage 36c), the casing includes a bypass flow passage (for example, the above-mentioned bypass flow passage 90) that bypasses an inlet of the nozzle flow passage (for example, the above-mentioned inlet 36i) and supplies the refrigerant flowing in the scroll flow passage to a position midway along the nozzle flow passage (for example, the position of the above-mentioned outlet 90b).

[0101] In a low-temperature environment of a refrigerator (for example, an environment where the turbine inlet temperature is approximately −70°C and the turbine outlet temperature is −90°C or lower), there is a risk that ice that has formed in narrow flow passages, such as the outlet of the nozzle flow passage, will grow and cause blockage of the nozzle flow passage. In this regard, in the electric turbomachine described in

[12] above, the high-pressure refrigerant flowing through the scroll flow passage passes through the bypass flow passage and is supplied as a jet to a position midway through the nozzle flow passage. Therefore, even if ice forms near the outlet of the nozzle flow passage, the jet coming out of the bypass flow passage can push the ice out of the nozzle flow passage, thereby suppressing the growth of ice in the nozzle flow passage. Therefore, blockage of the nozzle flow passage due to ice formation can be suppressed.

[0102]

[13] In some embodiments, in the electric turbomachine described in

[12] above, at least a part of the outlet of the bypass flow path (e.g., the above-mentioned outlet 90b) is arranged at a throat position (e.g., the above-mentioned throat position P0) where the flow path width in the nozzle flow path is minimum.

[0103] According to the electric turbomachine described in

[13] above, by arranging at least a part of the outlet of the bypass flow path at a throat position where icing is likely to occur in the nozzle flow path, it is possible to effectively suppress icing in the nozzle flow path.

[0104]

[14] In some embodiments, in the electric turbomachine described in

[12] or

[13] above, the casing includes a turbine housing (e.g., the above-mentioned turbine housing 40) that accommodates the turbine wheel and forms at least a part of the scroll flow path, and a nozzle mount (e.g., the above-mentioned nozzle mount 44) that forms the shroud-side flow path wall, the nozzle mount includes a first wall surface (e.g., the above-mentioned first wall surface 45) that faces away from the motor-side flow path wall and faces the turbine housing, the turbine housing includes a first opposing surface (e.g., the above-mentioned opposing surface 50a) that faces the first wall surface, a first gap (e.g., the above-mentioned first gap g1) is formed between the first wall surface of the nozzle mount and the first opposing surface of the turbine housing, the first gap is a part of the bypass flow path, and an inlet of the bypass flow path (e.g., the above-mentioned inlet 90a) is defined by the first wall surface of the nozzle mount and the first opposing surface of the turbine housing.

[0105] According to the electric turbomachine described in

[14] above, the first gap, which is the gap between the first wall surface of the nozzle mount and the opposing surface of the turbine housing, can be used as part of the bypass flow path, thereby making it possible to suppress icing in the nozzle flow path with a simple configuration.

[0106]

[15] In some embodiments, in the electric turbomachine described in

[14] above, a size of the first gap in the axial direction of the electric turbomachine increases toward the inlet of the bypass flow path.

[0107] According to the electric turbomachine described in

[15] above, the refrigerant flowing through the scroll passage can be guided to the bypass passage, thereby enhancing the effect of suppressing icing in the nozzle passage.

[0108]

[16] In some embodiments, in the electric turbomachine described in

[14] or

[15] above, the nozzle mount includes an inner circumferential surface facing radially inward of the electric turbomachine, the turbine housing includes a second opposing surface opposing the inner circumferential surface, a second gap is formed between the inner circumferential surface of the nozzle mount and the second opposing surface of the turbine housing, the second gap is a part of the bypass flow path, and an outlet of the bypass flow path is defined by the inner circumferential surface of the nozzle mount and the second opposing surface of the turbine housing.

[0109] According to the electric turbomachine described in

[16] above, the second gap, which is the gap between the inner circumferential surface of the nozzle mount and the second opposing surface of the turbine housing, can be used as part of the bypass flow path, thereby making it possible to suppress icing in the nozzle flow path with a simple configuration.

[0110]

[17] In some embodiments, in the electric turbomachine described in

[16] above, the size of the second gap in the radial direction varies depending on the circumferential position of the electric turbomachine, and a location where the size of the second gap in the radial direction is maximum is defined as a large gap portion, and for two adjacent fixed vanes among the plurality of fixed vanes that are sandwiched between the large gap portion, the fixed vane downstream of the large gap portion in the rotational direction of the turbine wheel is defined as a downstream fixed vane (e.g., the above-mentioned downstream fixed vane 26D), and the fixed vane upstream of the large gap portion in the rotational direction is defined as an upstream fixed vane (e.g., the above-mentioned upstream fixed vane 26U), the distance between the suction side of the downstream fixed vane (e.g., the above-mentioned suction side 26Dp) and the large gap portion (e.g., the above-mentioned distance dp) is smaller than the distance between the ventral side of the upstream fixed vane (e.g., the above-mentioned ventral side 26Us) and the large gap portion (e.g., the above-mentioned distance ds).

[0111] If ice forms on the suction side of the fixed vanes, the throat of the nozzle flow path is likely to narrow, which can have a significant impact on turbine performance. Therefore, as described in

[17] above, by making the distance between the suction side of the downstream fixed vane and the large gap smaller than the distance between the ventral side of the upstream fixed vane and the large gap, ice formation near the suction side of the fixed vanes can be effectively suppressed.

[0112] 2 Electric turbomachine 4 Motor 6A, 6B Rotating shaft 8 Turbine 10 Compressor 12 Rotor 14 Stator 16A Turbine side bearing 16B Compressor side bearing 18 Turbine wheel 20 Compressor impeller 22 Refrigerant flow path 24 Casing 26 Stationary vane 26D Downstream side stationary vane 26Dp Suction side 26U Upstream side stationary vane 26Us Pressure side 26a Leading edge 26b Trailing edge 28 Hub 30 Turbine blade 30a Tip 32 Scroll flow path 34 Wheel flow path 36 Intermediate flow path 36a, 36b Flow path wall surface 36c Nozzle flow path 36i, 90a Inlet 40 Turbine housing 42 Bearing housing 43 End portion 44 Nozzle mount 45 First wall surface 46 Scroll section 46a, 58 Part 48 Flange portion 49 Fastening member 50 Nozzle mount support portion 50a, 50b Opposing surface 51 Site 52 Cylindrical portion 53 Convex portion 54 Partition portion 56 Heat insulating mechanism 60 Hollow portion 62 Heat insulating material 64 Motor side flow path wall portion 66 Shroud side flow path wall portion 67 Shroud wall portion 67a Outer circumferential surface 68, 71, 81, 84 Fixing pin 68a, 71a, 81a, 84a Shaft portion 68b, 71b, 81b, 84b Head portion 69, 72, 82, 85, 86 Through hole 69a, 72a, 82a, 85a Large hole portion 69b, 72b, 82b, 85b Small hole portion 70, 73, 83, 87 Fitting hole 75 First groove 76 Second groove 77 First elastic member 78 Second elastic member 79 Rotation stop pin 80 Pin hole 90 Bypass flow path 90b Outlet 91 First flow path section 92 Second flow path section 93 Inner peripheral surface 94 Axial hole 95 Gap 96 Inclined hole H1 First plane P0 Throat position P1 Position W, W1, W2 Flow path width d1, d2, dp, ds Distance g1 First gap g2 Second gap gc Constant gap section gd Large gap section

Claims

1. An electric turbomachine for a refrigerator, comprising: a motor; and a turbine connected to the motor via a rotating shaft, wherein the turbine includes: a turbine wheel; a casing that houses the turbine wheel and forms a refrigerant flow path through which a refrigerant flows; and fixed vanes provided upstream of the turbine wheel in the refrigerant flow path, wherein the casing includes a partition configured to separate the motor from the refrigerant flow path of the turbine, and the partition is provided with a heat insulating mechanism for suppressing heat input from the motor to the refrigerant flowing through the refrigerant flow path, wherein the refrigerant flow path includes a scroll flow path provided on the outer periphery of the turbine wheel, and an intermediate flow path provided between the scroll flow path and the turbine wheel, and the casing includes a motor-side flow path wall that forms a flow path wall surface on the motor side of the intermediate flow path, and a shroud-side flow path wall that forms a flow path wall surface of the intermediate flow path on the opposite side to the motor, and the fixed vanes are fixed to the shroud-side flow path wall.

2. The electric turbomachine according to claim 1, wherein the casing includes a turbine housing that houses the turbine wheel and forms at least a part of the scroll flow path, and a nozzle mount that forms the shroud-side flow path wall, the fixed vanes are configured integrally with the nozzle mount by being welded to the nozzle mount or by being integrally molded with the nozzle mount, and the turbine includes a fixing member for fixing the nozzle mount to the turbine housing.

3. The electric turbomachine according to claim 2, wherein the fixing member is fixed to the turbine housing by passing through a through hole formed in the shroud-side flow path wall portion.

4. An electric turbomachine according to claim 2, wherein the nozzle mount includes an annular shroud wall portion that is connected to the shroud-side flow path wall portion and faces the tips of the turbine blades of the turbine wheel, and the fixing member is fixed to the turbine housing by passing through a through-hole formed in the shroud wall portion.

5. The electric turbomachine according to claim 2, wherein the nozzle mount includes a shroud wall portion connected to the shroud-side flowpath wall portion and facing the tips of the turbine blades of the turbine wheel, the shroud-side flowpath wall portion includes a first wall surface facing away from the motor-side flowpath wall portion and facing the turbine housing, a first groove extending along the circumferential direction of the electric turbomachine is formed in the first wall surface, and a second groove extending along the circumferential direction is formed in the outer peripheral surface of the shroud wall portion, and the turbine includes a first elastic member accommodated in the first groove and abutting against the turbine housing, and a second elastic member accommodated in the second groove and abutting against the turbine housing.

6. The electric turbomachine according to claim 1, wherein the casing includes a turbine housing that houses the turbine wheel and defines at least a part of the scroll flow passage, and the stationary vanes are welded to the turbine housing or integrally formed with the turbine housing.

7. An electric turbomachine as described in claim 2, wherein the fixing member is a fixing pin including a shaft portion and a head portion having an outer diameter larger than that of the shaft portion, the nozzle mount includes a first wall surface facing away from the motor-side flowpath wall portion and facing the turbine housing, a through hole is formed in a portion of the turbine housing adjacent to the first wall surface, a first hole communicating with the through hole is formed in the first wall surface, the fixing pin passes through the through hole, and the shaft portion of the fixing pin fits into the first hole in the first wall surface.

8. The electric turbomachine according to claim 2, wherein the fixing member is a fixing pin including a shaft portion and a head portion having an outer diameter larger than that of the shaft portion, the fixed vane has a first through hole formed therein that passes through in the axial direction of the electric turbomachine, the nozzle mount has a second through hole formed therein that communicates with the first through hole, and the turbine housing has an opposing surface that faces the nozzle mount and that communicates with the second through hole, the fixing pin passes through the first through hole of the fixed vane and the second through hole of the nozzle mount, and the shaft portion of the fixing pin fits into the first hole of the turbine housing.

9. The electric turbomachine according to claim 1, wherein the flow path width of the intermediate flow path in the axial direction of the electric turbomachine at the position of the leading edge of the fixed vane is greater than the flow path width of the intermediate flow path in the axial direction at the position of the trailing edge of the fixed vane.

10. The electric turbomachine according to claim 9, wherein, when a plane that passes through a position where the trailing edge of the fixed vane and the motor-side flow path wall portion are connected and is perpendicular to the axial direction of the electric turbomachine is defined as a first plane, the axial distance between the flow path wall surface on the opposite side from the motor in the intermediate flow path and the first plane increases toward the outside in the radial direction of the electric turbomachine.

11. The electric turbomachine according to claim 9, wherein, when a plane that passes through a position where the trailing edge of the fixed vane and the motor-side flow path wall portion are connected and is perpendicular to the axial direction of the electric turbomachine is defined as a first plane, the axial distance between the motor-side flow path wall surface in the intermediate flow path and the first plane increases toward the outside in the radial direction of the electric turbomachine.

12. The electric turbomachine according to claim 1, wherein the turbine includes a plurality of the fixed vanes arranged in the intermediate flow passage at intervals in the circumferential direction of the electric turbomachine, and when a flow passage formed between the plurality of fixed vanes in the circumferential direction is defined as a nozzle flow passage, the casing includes a bypass flow passage that bypasses an inlet of the nozzle flow passage and supplies the refrigerant flowing in the scroll flow passage to a position midway along the nozzle flow passage.

13. The electric turbomachine according to claim 12, wherein at least a portion of the outlet of the bypass flow passage is disposed at a throat position where a flow passage width of the nozzle flow passage is minimum.

14. The electric turbomachine according to claim 12, wherein the casing includes a turbine housing that houses the turbine wheel and forms at least a part of the scroll flow path, and a nozzle mount that forms the shroud-side flow path wall, the nozzle mount includes a first wall surface that faces away from the motor-side flow path wall and faces the turbine housing, the turbine housing includes a first opposing surface that faces the first wall surface, a first gap is formed between the first wall surface of the nozzle mount and the first opposing surface of the turbine housing, the first gap is a part of the bypass flow path, and an inlet of the bypass flow path is defined by the first wall surface of the nozzle mount and the first opposing surface of the turbine housing.

15. The electric turbomachine according to claim 14, wherein the size of the first gap in the axial direction of the electric turbomachine increases toward the inlet of the bypass flow path.

16. The electric turbomachine according to claim 14, wherein the nozzle mount includes an inner circumferential surface facing radially inward of the electric turbomachine, the turbine housing includes a second opposing surface opposing the inner circumferential surface, a second gap is formed between the inner circumferential surface of the nozzle mount and the second opposing surface of the turbine housing, the second gap is a part of the bypass flow path, and an outlet of the bypass flow path is defined by the inner circumferential surface of the nozzle mount and the second opposing surface of the turbine housing.

17. The electric turbomachine according to claim 16, wherein the size of the second gap in the radial direction varies depending on the circumferential position of the electric turbomachine, and a location where the size of the second gap in the radial direction is maximum is defined as a large gap portion, and for two adjacent fixed vanes among the plurality of fixed vanes that are sandwiched between the large gap portion, the fixed vane downstream of the large gap portion in the rotational direction of the turbine wheel is defined as a downstream fixed vane, and the fixed vane upstream of the large gap portion in the rotational direction is defined as an upstream fixed vane, and the distance between the suction side of the downstream fixed vane and the large gap portion is smaller than the distance between the ventral side of the upstream fixed vane and the large gap portion.

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