Rotating machinery

Abstract

A rotary machine is provided with: an electric motor (2) provided with a rotor (21) and a stator (22); a rotary shaft (3) that rotates by driving of the electric motor (2); an impeller (4) installed to the rotary shaft (3); an inner case (9) that surrounds the stator (22), and the stator (22) is fixed to the inner case (9); and an outer cover portion (8) that is externally attached to the inner case (9), and the outer cover portion (8) is provided with an inner peripheral surface (Sa) that faces an outer peripheral surface of the inner case (9) and a flow path groove (11) that is formed in the inner peripheral surface (Sa) and through which a refrigerant passes.

Description

Technical Field

[0001] This disclosure relates to rotating machinery. Background Technology

[0002] As a cooling structure for electric motors, the technologies disclosed in Patent Documents 1-4 are known, for example. Additionally, there are rotating machines such as turbochargers equipped with impellers. These rotating machines include an electric motor that rotates the impeller, either primarily or secondarily. A cooling flow path is provided near the electric motor, and the heat generated by the electric motor is suppressed using a refrigerant passing through the cooling flow path.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2006-033916

[0004] Patent Document 2: Japanese Patent Application Publication No. 2017-99281

[0005] Patent Document 3: Japanese Patent Application Publication No. 59-070162

[0006] Patent Document 4: Japanese Patent Application Publication No. 10-210702

[0007] In rotating machinery, there are more constraints when creating cooling flow paths through the structure around the stator of an electric motor and the configuration of the impeller. As a result, various problems may arise if the electric motor is not adequately cooled. Summary of the Invention

[0008] This disclosure describes rotating machinery capable of cooling an electric motor.

[0009] One aspect of this disclosure is a rotating machine comprising: an electric motor having a rotor and a stator; a rotating shaft that is rotated by the electric motor; an impeller mounted on the rotating shaft; an inner housing surrounding the stator, the stator being fixed to the inner housing; and an outer casing fitted onto the inner housing, the outer casing having an inner circumferential surface facing the outer circumferential surface of the inner housing, and a flow channel formed on the inner circumferential surface for refrigerant passage.

[0010] One aspect of this disclosure is a rotating machine comprising: an electric motor having a rotor and a stator; a rotating shaft that is rotated by the electric motor; an impeller mounted on the rotating shaft; an inner housing surrounding the stator and the stator being fixed to the inner housing; and an outer casing fitted onto the inner housing, the inner housing having ends on both sides along the axial direction of the rotating shaft, the outer casing having: an inner wall facing one end of one of the ends on both sides of the inner housing; and an inner wall groove provided in the inner wall for refrigerant to pass through.

[0011] According to certain methods of this disclosure, it is possible to cool an electric motor. Attached Figure Description

[0012] Figure 1 This is a cross-sectional view of a rotating machine according to one embodiment of the present disclosure.

[0013] Figure 2 This is an exploded perspective view showing a portion of the rotating machinery in the embodiment.

[0014] Figure 3 It is a three-dimensional view showing the inner circumferential surface of the motor housing.

[0015] Figure 4 It is an explanatory diagram that roughly unfolds the cooling flow path on a plane and schematically shows the refrigerant flow in the cooling flow path.

[0016] Figure 5 This is an exploded perspective view showing a portion of a rotating machine according to other embodiments.

[0017] Figure 6 It is an explanatory diagram that schematically unfolds the cooling flow path involved in other embodiments on a plane and schematically shows the refrigerant flow in the cooling flow path. Detailed Implementation

[0018] One example of this disclosure is a rotating machine comprising: an electric motor having a rotor and a stator; a rotating shaft that is driven to rotate by the electric motor; an impeller mounted on the rotating shaft; an inner housing surrounding the stator, and the stator being fixed to the inner housing; and an outer casing fitted onto the inner housing. In this rotating machine, the outer casing has an inner circumferential surface facing the outer circumferential surface of the inner housing, and a flow channel formed on the inner circumferential surface for refrigerant to pass through.

[0019] In one example of rotating machinery, the stator of an electric motor is fixed to an inner housing, and an outer casing is fitted around the inner housing. A flow channel for refrigerant is formed on the inner circumferential surface of the outer casing, and the flow channel is positioned around the inner housing. The stator of the electric motor is cooled via the inner housing using the refrigerant flowing through the flow channel. As a result, the electric motor can be cooled. Here, the flow channel is formed on the outer casing in the main body. That is, there are fewer constraints on the dimensions, structure, etc., of the inner housing used to form the flow channel. Therefore, for example, it is easy to thin the wall thickness of the inner housing to cool the stator uniformly over a wider range.

[0020] In some examples, the structure may be configured such that the inner housing has ends on both sides along the axial direction of the rotation shaft, and the outer cover has: a side wall having the aforementioned inner circumferential surface; an inner wall facing one end of one of the two ends of the inner housing; and a return groove provided on the inner wall and communicating with the flow path groove. Because a return groove for refrigerant to pass through is formed on the inner wall, cooling can be achieved on one end of the stator fixed to the inner housing.

[0021] In some examples, the flow path can be configured such that the flow path has multiple main channels extending axially, the multiple main channels being arranged side by side in the circumferential direction of the inner shell and communicating with each other via return channels. Since the multiple main channels are arranged side by side in the circumferential direction of the inner shell and communicate with each other via return channels, the stator can be cooled from a wider circumferential range of the inner shell.

[0022] In some examples, the configuration may include: a sidewall with a stepped portion axially positioned opposite the inner wall and having an enlarged inner diameter; a flow channel with a connecting groove that connects multiple main channels and opens at the stepped portion; and an inner shell with a flange that abuts against the stepped portion to close the connecting groove. Because the multiple main channels are interconnected via the connecting groove, a wider range of cooling can be achieved using a shared refrigerant.

[0023] In some examples, the flow path can be configured such that the flow path has an inlet for receiving refrigerant and an outlet for discharging refrigerant, and the flow path and return section form a single-pass flow path connecting the inlet and outlet. By forming a single-pass flow path, the number of refrigerant stagnation points can be reduced, facilitating smooth refrigerant flow.

[0024] In some cases, the flow path profile of the return channel can be smaller than the maximum flow path profile of the flow channel. The flow velocity in the return channel is higher than that in the flow channel, which is beneficial for improving cooling efficiency at the inner wall.

[0025] In some examples, the inner wall can be configured such that, axially, at least a portion of the return channel overlaps with the impeller. This allows both the stator and the impeller to be cooled using refrigerant passing through the return channel.

[0026] In some examples, the inner shell may be configured such that it has an outer peripheral surface that contacts the inner peripheral surface of the outer casing, wherein at least the area of ​​the inner shell facing the flow channel is flat. If the area of ​​the inner shell facing the flow channel is flat, a seal (becoming airtight or liquidtight) can be achieved when the flow channel, which serves as the flow path for the refrigerant, is closed.

[0027] In some examples, the flow path can be configured such that the flow path has a connecting groove that connects multiple main grooves to each other, with one end of the main groove connected to the return groove and the other end connected to the connecting groove.

[0028] In some examples, the configuration may be such that multiple connecting slots are arranged circumferentially, multiple return slots are arranged circumferentially, and the connecting slots and return slots are alternately arranged circumferentially.

[0029] One example of this disclosure is a rotating machine comprising: an electric motor having a rotor and a stator; a rotating shaft that is rotated by the electric motor; an impeller mounted on the rotating shaft; an inner housing surrounding the stator and the stator being fixed to the inner housing; and an outer casing fitted onto the inner housing, the inner housing having ends on both sides along the axial direction of the rotating shaft, the outer casing having: an inner wall facing one end of one of the ends on both sides of the inner housing; and an inner wall groove provided in the inner wall for refrigerant to pass through.

[0030] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. Furthermore, in the description of the drawings, the same reference numerals are used to denote the same elements, and repeated descriptions are omitted.

[0031] Figure 1 and Figure 2 This invention represents an example of a rotating machine 1, specifically an electric booster. The rotating machine 1 of this invention includes an electric motor 2, a rotating shaft 3 that rotates under the drive of the electric motor 2, and a compressor impeller 4 mounted on the rotating shaft 3. Furthermore, the rotating machine 1 includes a frequency converter 6 that controls the drive of the electric motor 2.

[0032] The electric motor 2 includes a rotor 21 fixed to a rotating shaft 3 and a stator 22 arranged to surround the rotor 21. The stator 22 has teeth 22a and coils 22b wound around the teeth 22a. The stator housing 9 (an example of an inner housing) is arranged to surround the electric motor 2, and in particular to surround the stator 22. The stator 22 is fixed inside the stator housing 9.

[0033] The stator housing 9 is a bottomed cylindrical shape and has a cylindrical peripheral wall 91 on which the stator 22 is fixed. The peripheral wall 91 is arranged along the axial direction Da of the rotation axis 3. The stator housing 9 has a bottom wall 92 located at one end of the peripheral wall 91 along the axial direction Da. An opening is formed in the center of the bottom wall 92, and a bearing 31 supporting the rotation axis 3 is fixed in the opening. The stator housing 9 has an end located on the opposite side of the bottom wall 92, and this end is open. A flange 93 is formed on the outer periphery of the open end. In the following description, the outer peripheral surface Sb of the stator housing 9 refers to the outer peripheral surface 91a of the peripheral wall 91 and the outer peripheral surface 92a of the bottom wall 92.

[0034] The rotating machinery 1 includes an impeller housing 70 that houses a compressor impeller 4 and a motor housing 8 that houses an electric motor 2. The motor housing 8 is connected to the compressor impeller 4 along the axial direction Da of the rotating shaft 3. Furthermore, the rotating machinery 1 includes an inner cover 71 that closes the open end of the stator housing 9 and an outer cover 72 that closes the open portion of the motor housing 8. A central hole is formed in the inner cover 71 for the rotating shaft 3 to pass through. A cylindrical sleeve 73 is provided between the inner cover 71 and the outer cover 72. A bearing 32 that supports the rotating shaft 3 and enables it to rotate is fixed inside the sleeve 73.

[0035] The motor housing 8 includes: a motor housing 81 (an example of an outer cover), which is externally mounted to the stator housing 9 and substantially houses the electric motor 2 inside; and a frequency converter housing 82, which houses the frequency converter 6. The frequency converter 6, which controls the drive of the electric motor 2, is housed in the frequency converter housing 82. A cover 61 that covers the frequency converter 6 is fixed to the frequency converter housing 82.

[0036] The inner circumferential surface Sa of the motor housing 81 substantially abuts against the outer circumferential surface Sb of the stator housing 9, and a cooling flow path F is formed between the inner circumferential surface Sa of the motor housing 81 and the outer circumferential surface Sb of the stator housing 9. In the cooling flow path F, a coolant C (see reference) is used to cool the electric motor 2. Figure 4 (Passed.) The construction of the cooling flow path F will be described below.

[0037] The motor housing 81 has a side wall 83 that surrounds the peripheral wall 91 of the stator housing 9. An inner wall 84 is provided at one end of the side wall 83 on the axial direction Da (see reference). Figure 3 The end on the opposite side (hereinafter referred to as "open end 85") is open. A bearing 31 supporting the rotating shaft 3 and enabling it to rotate is fixed in the inner wall 84. The side wall 83 has an inner peripheral surface 83a that faces the outer peripheral surface 91a of the peripheral wall 91 of the stator housing 9. A stepped portion 83b is formed in the inner peripheral surface 83a, which widens in inner diameter from one end to the other end. The flange portion 93 of the stator housing 9 abuts against the stepped portion 83b. Furthermore, in the following description, the inner peripheral surface Sa of the motor housing portion 81 refers to the inner peripheral surface 83a of the side wall 83 and the inner peripheral surface 84a of the inner wall 84.

[0038] The stator housing 9 is inserted into the side wall 83 from the open end 85 (see reference). Figure 2The stator housing 9 has a flange portion 93, and a sealing member 94 is assembled at the outer peripheral end 93a of the flange portion 93. The flange portion 93 moves along the axial direction Da. The sealing member 94 follows the movement of the flange portion 93 and moves in a state of sliding contact with the inner peripheral surface 83a of the sidewall 83. The flange portion 93 moves to a position abutting against the stepped portion 83b. By abutting the flange portion 93 against the stepped portion 83b, the sealing member 94 can ensure the sealing performance (air tightness or liquid tightness) of the cooling flow path F. Furthermore, in this embodiment, the sealing member 94 moves in a state of sliding contact with the inner peripheral surface 83a of the sidewall 83. Therefore, even if the flange portion 93 is slightly offset in the axial direction Da, the basic sealing performance of the cooling flow path F can be ensured.

[0039] like Figure 2 , Figure 3 and Figure 4 As shown, a flow path groove 11 for refrigerant C to pass through is formed on the inner peripheral surface 83a of the sidewall 83. The flow path groove 11 has a plurality of main groove portions 12 provided on the inner peripheral surface 83a of the sidewall 83, and a connecting groove portion 13 connecting the plurality of main groove portions 12. When used as a cooling flow path F, the connecting groove portion 13 is open at the step portion 83b of the sidewall 83, and abuts against the flange portion 93 of the stator housing 9 through the step portion 83b, and the connecting groove portion 13 is closed, thus failing to perform its function as a cooling flow path F.

[0040] The main groove 12 is a longitudinally elongated groove extending along the axial direction Da of the rotation axis 3. Multiple main grooves 12 are arranged side-by-side at equal intervals in the circumferential direction Db of the stator housing 9, i.e., in the rotational direction of the rotation axis 3. Furthermore, each main groove 12 can be configured as a cone shape, becoming wider the further away from the inner wall 84. As described above, the connecting groove 13 opens at the stepped portion 83b of the side wall 83, making it difficult for the connecting groove 13 to become a recessed section when the motor housing 8 (motor housing 81) is die-cast. Furthermore, by configuring the main grooves 12 as cones, it is also difficult for the flow path groove 11 as a whole to become a recessed section. As a result, the burden of finishing processes such as machining can be reduced, and efficient manufacturing can be achieved by improving workability during manufacturing.

[0041] The inner peripheral surface 84a of the inner wall 84 faces the bottom wall 92 (one end) of the stator housing 9. A return groove 14 (an example of an inner wall groove) is formed on the inner peripheral surface 84a of the inner wall 84. The return groove 14 communicates with the flow path groove 11 and becomes part of the cooling flow path F. The return groove 14 connects the ends of the multiple main grooves 12 on the inner wall 84 side to each other in a manner that allows refrigerant C to communicate. On the other hand, a connecting groove 13 is provided on the side opposite to the inner wall 84. The connecting groove 13 connects the ends of the multiple main grooves 12 to each other in a manner that allows refrigerant C to communicate. That is, one end of the multiple main grooves 12 is connected to the return groove 14, resulting in adjacent main grooves 12 communicating with each other. In addition, the other end of the multiple main grooves 12 is connected to the connecting groove 13, resulting in adjacent main grooves 12 communicating with each other.

[0042] When the stator housing 9 is assembled inside the motor housing 81, the flow path groove 11 and the return groove 14 are closed by the outer peripheral surface Sb of the stator housing 9, forming a cooling flow path F for the refrigerant C to pass through. The cooling flow path F in this embodiment is formed as a one-pass flow path. A one-pass flow path refers to a flow path that connects two parts in a non-branching manner. In this embodiment, the connecting groove 13 and the return groove 14 are alternately arranged in the circumferential direction Db. The refrigerant C passing through the connecting groove 13 flows unidirectionally along the main groove 12 (outbound flow). Then, the refrigerant C flows in reverse through the return groove 14, and at this time flows in the opposite direction along the adjacent main groove 12 (return flow). As a result, a one-pass flow path is formed in which outbound flow and return flow alternate. An inlet 15a for receiving refrigerant C is provided at the upstream end of the one-pass flow path. An outlet 15b for discharging refrigerant C is provided at the downstream end of the single-pass flow path. By forming a single-pass flow path, the stagnation points of refrigerant C can be reduced, thereby facilitating the smooth flow of refrigerant C.

[0043] In this embodiment, the main channel section 12 near the connecting channel section 13 of the flow channel 11 has the largest flow path cross-section, becoming the maximum flow path cross-section. In contrast, the flow path cross-section of the return channel section 14 is smaller than the maximum flow path cross-section. By making the flow path cross-section of the return channel section 14 smaller than the maximum flow path cross-section of the flow channel 11, the flow velocity in the return channel section 14 is faster than the flow velocity in the flow channel 11, thereby enabling cooling at the inner wall 84.

[0044] Additionally, the inner wall 84 with the return groove 14 is provided on the compressor impeller 4 (see reference). Figure 1The return groove 14 is located between the stator 22 and the compressor impeller 4. Furthermore, at least a portion of the return groove 14 is configured to overlap with the compressor impeller 4 in the axial direction Da. As a result, both the stator 22 and the compressor impeller 4 can be cooled using the refrigerant C passing through the return groove 14. Moreover, the phrase "at least a portion of the return groove 14 is configured to overlap with the compressor impeller 4 in the axial direction Da" means that, when viewed from the inner wall 84 in the axial direction Da, at least a portion of the return groove 14 overlaps with the compressor impeller 4.

[0045] A portion of the outer peripheral surface Sb of the stator housing 9, namely the outer peripheral surface 91a of the peripheral wall 91, is a part of the outer peripheral surface Sb of the stator housing 9. The outer peripheral surface 91a contacts the inner peripheral surface 83a of the side wall 83 of the motor housing 81. The outer peripheral surface 91a is a substantially flat, cylindrical surface without any irregularities, and is flat at least in the area facing the flow channel 11. As a result, when the flow channel 11, which serves as the cooling flow channel F, is closed, a seal (becoming airtight or liquid-tight) can be achieved.

[0046] Next, the operation and effects of the rotating machinery 1 according to the embodiment will be explained. The rotating machinery 1 includes a stator housing 9 and a motor housing 81 externally mounted on the stator housing 9. A flow channel 11 through which refrigerant C passes is formed on the inner peripheral surface Sa of the motor housing 81, and the flow channel 11 is disposed around the stator housing 9. The stator 22 of the electric motor 2 is cooled by the refrigerant C passing through the flow channel 11 via the stator housing 9. As a result, the electric motor 2 can be cooled. In addition, a cooling flow channel F (the flow channel 11 through which refrigerant C passes) is provided between the stator housing 9 and the motor housing 81. Therefore, it is easy to obtain a cooling flow channel F with a stable shape, and it is easy to guide the refrigerant C with a faster flow rate within a narrower range, thus easily improving the cooling performance.

[0047] Furthermore, in this embodiment, since the flow channel 11, which can serve as the cooling flow path F, is formed in the motor housing 81, the range of forming methods for the stator housing 9 is expanded. For example, the stator housing 9 can also be formed by deep drawing steel, which reduces the manufacturing cost per unit of the stator housing 9. Moreover, by using steel as the material for the stator housing 9, the interlocking of different types of metals is eliminated, thus improving reliability in terms of quality. Alternatively, the stator housing 9 can also be manufactured by stamping, machining, or other processes on tubing.

[0048] Furthermore, the flow channel 11 is formed on the motor housing 81 in the main body. That is, the constraints on the size, structure, etc., for forming the flow channel 11 are reduced regarding the stator housing 9. As a result, for example, it is easy to make the wall thickness of the stator housing 9 thinner and cool the stator 22 uniformly over a wider range, and cooling of the electric motor 2 can be performed. In addition, in this embodiment, the outer peripheral surface Sb of the stator housing 9 is flat, which is an excellent way to seal. However, if it is permissible, a groove that becomes part of the cooling flow channel F may be provided auxiliaryly on the outer peripheral surface Sb of the stator housing 9, given the constraints related to the strength and structure of the stator housing 9.

[0049] Furthermore, the motor housing 81 has an inner wall 84, on which a return groove 14 communicating with the flow path groove 11 is formed. By forming the return groove 14 on the inner wall 84, the inner end (one-sided end) of the stator 22 fixed to the stator housing 9 can be cooled. In addition, since the return groove 14 is provided on the inner wall 84 rather than the side wall 83 of the motor housing 81, the return groove 14 is less likely to become a recessed part when the motor housing 81 is die-cast, thus improving formability.

[0050] Furthermore, the flow path groove 11 includes a plurality of main groove portions 12. These main groove portions 12 are arranged side-by-side on the circumferential Db of the stator housing 9 and communicate with each other via return groove portions 14. As a result, the stator 22 can be cooled from a wider range of the circumferential Db of the stator housing 9. In particular, since the plurality of main groove portions 12 involved in this embodiment are arranged side-by-side at equal intervals, it is advantageous for uniformly cooling the stator 22. This "arranged side-by-side at equal intervals" refers to a state where small errors are allowed and the arrangement is at substantially equal intervals.

[0051] Furthermore, since the multiple main grooves 12 are interconnected via the connecting grooves 13, a wider range of cooling can be achieved using a shared refrigerant C. Also, since the connecting grooves 13, which connect the multiple main grooves 12, are open at the stepped portion 83b, when the motor housing portion 81 is formed by die casting, the main grooves 12 and the connecting grooves 13 are less likely to become recessed portions, thus improving formability.

[0052] Next, refer to Figure 5 and Figure 6 Other embodiments of the rotating machine 1A will be described. Furthermore, the rotating machine 1A according to these other embodiments has the same construction and structure as the rotating machine 1 described above. It can essentially perform the same function and effect as the rotating machine 1. Therefore, in the following description, the focus will be on the differences, and the same reference numerals will be used for the same construction and structure, with detailed descriptions omitted.

[0053] Rotating machinery 1A includes: a stator housing 9, which surrounds a stator 22 (see reference). Figure 1 The stator 22 is fixed to the stator housing 9; and the motor housing 81 is externally mounted to the stator housing 9. The inner peripheral surface Sa of the motor housing 81 faces the outer peripheral surface Sb of the stator housing 9. The motor housing 81 has a side wall 83, and the inner peripheral surface 83a of the side wall 83 faces the outer peripheral surface 91a of the peripheral wall 91 of the stator housing 9. A flow channel 11 for refrigerant C to pass through is formed on the inner peripheral surface 83a of the side wall 83.

[0054] The flow path 11 includes multiple main groove sections 12 and connecting groove sections 13. Each main groove section 12 is a longitudinally elongated groove along the axial direction Da of the rotation shaft 3. Multiple main groove sections 12 are arranged side-by-side at equal intervals along the circumferential direction Db of the stator housing 9. One of the main groove sections 12 has a refrigerant inlet 15a, and a refrigerant outlet 15b is formed in a main groove section 12 adjacent to the main groove section 12 with the inlet 15a. Except for the areas dividing the main groove section 12 with the inlet 15a and the main groove section 12 with the outlet 15b, the connecting groove sections 13 substantially cover the entire circumference Db, connecting the multiple main groove sections 12 in a manner that allows them to communicate.

[0055] The motor housing 81 has an inner wall 84 facing the bottom wall 92 of the stator housing 9. A return groove 14 is provided on the inner wall 84. Except for the area that divides the main groove 12 of the inlet 15a and the main groove 12 of the outlet 15b, the return groove 14 basically covers the entire circumference Db and is connected in a way that allows multiple main grooves 12 to be connected.

[0056] In rotating machinery 1A, similar to rotating machinery 1 described above, a flow path 11 for refrigerant C is formed on the inner circumferential surface Sa of the motor housing 81. The flow path 11 is disposed around the stator housing 9. The stator 22 of the electric motor 2 is cooled by the refrigerant C passing through the flow path 11 via the stator housing 9. As a result, the electric motor 2 can be cooled. Furthermore, the flow path 11 is formed on the main body of the motor housing 81. That is, there are fewer constraints on the size, structure, etc. of the flow path 11 for forming the stator housing 9 inside the motor housing 81. Therefore, it is easy to improve the cooling performance for cooling the electric motor 2. In addition, the connecting groove 13 and the return groove 14 involved in this embodiment are formed as a plurality of main grooves 12 connected throughout the whole, and are not formed as a single-pass flow path.

[0057] This disclosure is not limited to the embodiments described above. For example, in the embodiments described above, an electric booster was described as an example of rotating machinery, but it can be widely applied to rotating machinery that has an impeller that rotates by the drive of an electric motor, and for example, it can also be an electrically assisted booster.

[0058] In addition, the flow channel forming the cooling flow path can take various shapes, such as a shape along the circumference of the stator housing, a wave shape, etc.

[0059] Explanation of reference numerals in the attached figures:

[0060] 1, 1A… Rotating machinery; 2… Electric motor; 3… Rotating shaft; 4… Compressor impeller; 9… Stator housing; 8… Motor housing; 11… Flow channel; 12… Main channel; 13… Connecting channel; 14… Return channel (inner wall channel); 15a… Inlet; 15b… Outlet; 21… Rotor; 22… Stator; 81… Motor housing (outer cover); 83… Side wall; 84… Inner wall; 83b… Stepped section; 93… Flange; Sa… Inner circumferential surface; Sb… Outer circumferential surface.

Claims

1. A rotating machine, characterized in that, have: An electric motor, which has a rotor and a stator; A rotating shaft that rotates by being driven by the electric motor; An impeller is mounted on the rotating shaft; An inner shell that surrounds the stator, and the stator being fixed to the inner shell; and The outer cover is fitted onto the inner shell. The outer casing has an inner peripheral surface that faces the outer peripheral surface of the inner shell, and a flow channel formed on the inner peripheral surface for refrigerant to pass through. The inner shell has ends on both sides along the axial direction of the rotating shaft. The outer casing includes: a sidewall having the inner circumferential surface; an inner wall facing one end of one of the two ends of the inner shell; and a return groove disposed on the inner wall and communicating with the flow path groove. The flow path groove has multiple main groove portions extending along the axial direction. The plurality of main grooves are arranged side by side in the circumferential direction of the inner shell. The main groove is formed in a conical shape, with its width increasing in the circumferential direction of the inner shell as it moves further away from the inner wall. The sidewall has a stepped portion, which is located on the side opposite to the inner wall in the axial direction and has an enlarged inner diameter. The flow path groove has a connecting groove that connects the plurality of main grooves to each other, and is open at the step portion. The inner shell has a flange portion that abuts against the stepped portion to close the connecting groove portion. A sealing member is provided at the outer peripheral end of the flange portion. The sealing member moves in a state of sliding contact with the inner peripheral surface of the sidewall as the flange portion moves.

2. The rotating machinery according to claim 1, characterized in that, The multiple main slots are interconnected via the return slots.

3. The rotating machinery according to claim 1 or 2, characterized in that, The flow channel has an inlet for receiving the refrigerant and an outlet for discharging the refrigerant. The flow path groove and the return groove form a single-pass flow path connecting the inlet and the outlet.

4. The rotating machinery according to claim 1 or 2, characterized in that, The flow path profile of the return channel is smaller than the maximum flow path profile of the flow path channel.

5. The rotating machinery according to claim 1 or 2, characterized in that, The inner wall is disposed between the impeller and the stator. In the axial direction, at least a portion of the return groove is configured to overlap with the impeller.

6. The rotating machinery according to claim 1 or 2, characterized in that, The inner shell has an outer peripheral surface that contacts the inner peripheral surface of the outer cover. In the outer peripheral surface, at least the area of ​​the inner shell facing the flow channel is flat.

7. The rotating machinery according to claim 1, characterized in that, The flow path groove includes a connecting groove that connects the plurality of main groove sections to each other. One end of the main groove is connected to the return groove, and the other end is connected to the connecting groove.

8. The rotating machinery according to claim 7, characterized in that, The connecting grooves are arranged in multiple ways along the circumferential direction. The return slots are arranged in multiple ways along the circumferential direction. The connecting groove and the returning groove are arranged alternately in the circumferential direction.

9. A rotating machine, characterized in that, have: An electric motor, which has a rotor and a stator; A rotating shaft that rotates by being driven by the electric motor; An impeller is mounted on the rotating shaft; An inner shell that surrounds the stator, and the stator being fixed to the inner shell; and The outer cover is fitted onto the inner shell. The inner shell has ends on both sides along the axial direction of the rotating shaft. The outer casing includes: an inner wall facing one of the two ends of the inner shell; an inner wall groove disposed on the inner wall for refrigerant to pass through; an inner peripheral surface facing the outer peripheral surface of the inner shell; and a main groove formed on the inner peripheral surface and communicating with the inner wall groove for refrigerant to pass through. The main groove extends axially along the rotation axis. The main groove is formed in a conical shape, with its width increasing in the circumferential direction of the inner shell as it moves further away from the inner wall. The outer cover portion includes a stepped portion, which is located on the side opposite to the inner wall in the axial direction, and has an enlarged inner diameter. The inner shell has a flange portion that abuts against the stepped portion. A sealing member is provided at the outer peripheral end of the flange portion. The sealing member moves in a state of sliding contact with the inner peripheral surface, following the movement of the flange portion.

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