Motor system

Abstract

To provide a motor system that can achieve both of reduction of stirring resistance loss during high-speed rotation and cooling of a stator coil.SOLUTION: A motor system includes: refrigerant supply passages 18 that each communicate with a sliding surface 22 of a sliding bearing 20 through a housing 15; and injection passages 32 that each open from the sliding surface 22 into an internal space 15b of the housing 15. Each of the sliding bearings 20 is configured to be lubricated by a CO2 refrigerant R supplied to a support space 22a between the sliding bearing 20 and a rotor shaft 13 through the refrigerant supply passages 18. The injection passages 32 are oriented such that the CO2 refrigerant R injected from the injection passage 32 reaches a coil 12b wound around a stator 12.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a motor system, and particularly to a motor system having a bearing portion.

Background Art

[0002] Conventionally, a technique of cooling a coil end by injecting oil onto the coil end wound around a stator of an electric motor is known (see, for example, Patent Document 1). In the electric motor of Patent Document 1, oil is introduced into a hollow rotor shaft of the electric motor, and the oil jets out of the rotor shaft to the outside through through-holes formed in the circumferential surface of the rotor shaft. The jetted oil is directed toward the coil end through a member attached to the rotor shaft to cool the coil end.

[0003] Generally, a rotor shaft of an electric motor is configured to be supported by a rolling bearing or a sliding bearing. In the electric motor of Patent Document 1, the rotor shaft is supported by a rolling bearing.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Generally, when the rotational speed of an electric motor becomes high (for example, more than 30,000 rmp), rolling fatigue becomes a problem in a rolling bearing. To avoid this, in such a super-high-speed rotating motor, an oil-lubricated sliding bearing may be employed instead of a rolling bearing. In an oil-lubricated sliding bearing, oil is supplied to the sliding bearing. However, in this case, in a super-high-speed rotating motor, due to the viscosity of the oil, stirring resistance loss during high-speed rotation of the rotor shaft becomes a problem.

[0006] The present invention was made to solve the problems of the prior art described above, and aims to provide a motor system that can achieve both a reduction in stirring resistance loss during high-speed rotation and cooling of the stator coils. [Means for solving the problem]

[0007] To achieve the above objective, the motor system of the present invention comprises a stator, a rotor, a rotor shaft fixed to the rotor and extending in the axial direction, a sliding bearing that rotatably supports the rotor shaft, and a housing that holds the sliding bearing, further comprising a refrigerant supply passage that communicates with the sliding surface of the sliding bearing relative to the rotor shaft, at least through the housing, and an injection passage having an opening that penetrates at least the sliding bearing from the sliding surface and opens into the internal space of the housing 15, wherein the sliding bearing is configured to be lubricated by CO2 refrigerant supplied to the support space between the sliding bearing and the rotor shaft through the refrigerant supply passage, and the injection passage is directed to cause the CO2 refrigerant injected from the injection passage to reach the coil wound around the stator.

[0008] In the present invention configured as described above, the motor system can lubricate the sliding surface of the sliding bearing by supplying CO2 refrigerant to the support space between the sliding bearing and the rotor shaft. The motor system also injects the lubricated CO2 refrigerant from the support space through an injection passage into the internal space of the housing. The injection passage is directed towards the stator coil, allowing the coil, which is a high-temperature part of the motor, to be cooled. Thus, in the present invention, CO2 refrigerant can be used for both lubricating the sliding bearing and cooling the motor. Therefore, the motor system of the present invention can achieve both a reduction in stirring resistance loss during high-speed rotation and cooling of the stator coil.

[0009] In this invention, the CO2 refrigerant can be in the form of a supercritical fluid when supplied to the sliding bearing. This supercritical fluid expands as it is ejected from the support space through the injection passage into the housing, and displaces into a gas-liquid mixture state. Furthermore, this gas-liquid mixture evaporates through heat exchange with the stator coils, and displaces into a gas.

[0010] Furthermore, in the present invention, preferably, the injection passage extends toward the coil so that the CO2 refrigerant injected from the injection passage reaches the coil directly. With the present invention configured in this way, the CO2 refrigerant flowing from the support space can be directed by the injection passage and released into the internal space of the housing.

[0011] Furthermore, in the present invention, preferably, the openings of the injection passage are arranged in a ring shape around the circumferential direction of the rotor shaft. With the present invention configured in this way, CO2 refrigerant is injected from the multiple openings toward multiple locations on the coil, so that the coil can be cooled more uniformly in the circumferential direction.

[0012] Furthermore, the present invention preferably further includes a refrigerant circulation system that supplies CO2 refrigerant to a refrigerant supply passage and recovers the CO2 refrigerant from within the housing. With the present invention configured in this way, a motor system comprising a refrigerant circulation system and a motor can be mounted, for example, on a vehicle.

[0013] Furthermore, in the present invention, preferably, the refrigerant circulation system includes a compressor that compresses gaseous CO2 refrigerant recovered from the housing to produce supercritical CO2 refrigerant fluid, and a condenser (heat exchanger) that condenses the CO2 refrigerant output from the compressor, exchanges heat with the external environment, and supplies the supercritical CO2 refrigerant fluid to the refrigerant supply passage. With the present invention configured in this way, the gaseous CO2 refrigerant after heat exchange in the motor is compressed by the compressor to form a high-temperature, high-pressure supercritical fluid (compression stroke). Next, the compressed CO2 refrigerant is condensed in the condenser to a medium-temperature, high-pressure state (condensation stroke). Furthermore, the condensed CO2 refrigerant is expanded in the motor to a low-temperature, low-pressure gas-liquid mixture state (expansion stroke). Finally, it is evaporated by heat exchange in the motor to produce high-temperature, low-pressure gaseous CO2 refrigerant (evaporation stroke). In the present invention, a refrigeration cycle can be formed in this way.

[0014] Furthermore, the present invention preferably includes a flow control valve for adjusting the flow rate of CO2 refrigerant flowing through the refrigerant supply passage. With the present invention configured in this way, by adjusting the opening degree of the flow control valve, the flow rate of CO2 refrigerant supplied to the sliding bearing can be adjusted, and the injection flow rate of CO2 refrigerant released into the internal space of the housing via the sliding bearing can be adjusted.

[0015] Furthermore, in the present invention, preferably, the refrigerant supply passage is formed to penetrate the sliding bearing and communicate with the sliding surface. With the present invention configured in this way, for example, a supercritical fluid CO2 refrigerant can be directly supplied to the sliding surface of the sliding bearing via the refrigerant supply passage. [Effects of the Invention]

[0016] The motor system according to the present invention makes it possible to reduce stirring resistance loss during high-speed rotation and to cool the stator coils at the same time. [Brief explanation of the drawing]

[0017] [Figure 1] This is a schematic diagram of a motor system according to an embodiment of the present invention. [Figure 2]It is an explanatory diagram of a refrigerant cycle according to an embodiment of the present invention. 4> [Figure 3] It is an explanatory diagram of a bearing according to an embodiment of the present invention. [Figure 4] It is an explanatory diagram of a bearing according to an embodiment of the present invention. [Figure 5] It is an explanatory diagram of a bearing according to a modified example of an embodiment of the present invention. [Figure 6] It is an explanatory diagram of a bearing according to an embodiment of the present invention.

Mode for Carrying Out the Invention

[0018] Hereinafter, a motor system according to an embodiment of the present invention will be described with reference to the accompanying drawings. [Overall Configuration] First, referring to FIG. 1, the overall configuration of the motor system according to the present embodiment will be described. FIG. 1 is a schematic configuration diagram of the motor system according to the present embodiment. The motor system S shown in FIG. 1 is mounted on a vehicle such as an electric vehicle, for example, and can provide a rotational driving force to the vehicle.

[0019] The motor system S includes a motor (electric motor) 1 and a refrigerant circulation system ⑧. The motor 1 provides a rotational driving force to the vehicle. The refrigerant circulation system 8 is configured to circulate the refrigerant R in a refrigeration cycle and cool the motor 1. That is, in this refrigeration cycle, the expansion stroke and evaporation stroke of the refrigerant R are executed in the motor 1, and the compression stroke and condensation stroke of the refrigerant R are executed in the refrigerant circulation system 8. In the present embodiment, it is preferable to use CO₂ refrigerant, which is a natural refrigerant, as the refrigerant R. Note that, as the refrigerant R, a natural refrigerant and oil may be mixed and used at a predetermined mixing ratio.

[0020] [Configuration of Refrigerant Circulation System] The refrigerant circulation system 8 includes a compressor (compressor) 81 for compressing the refrigerant R, a heat exchanger (condenser) 83 including a condenser, a fan, etc. for cooling the refrigerant R compressed by the compressor 81, a pipe 85, and valves (not shown). The motor 1 is incorporated in the refrigerant circulation system 8.

[0021] [Configuration of the motor] The motor 1 according to the present embodiment includes a rotor 11, a stator 12, a rotor shaft (rotating shaft) 13 fixed to the rotor 11 and extending in the axial direction, a pair of bearings (sliding bearings) 20 that rotatably support the rotor shaft 13, and a housing 15 that houses and supports the rotor 11, the stator 12, the rotor shaft 13, the bearings 20, etc. A sealing member 16 is provided to seal between the housing 15 and the rotor shaft 13. One end of the rotor shaft 13 is connected to a vehicle's transaxle (not shown), etc.

[0022] The substantially cylindrical stator 12 is formed by winding a coil 12b around a stator core 12a. As shown in FIG. 1, when the coil 12b is wound around the stator core 12a, coil ends 12c project from both axial ends of the stator core 12a. The rotor 11 has a rotor core and a plurality of permanent magnets attached to the rotor core. The rotor shaft 13 is fixed to the rotor core. The rotor 11 is configured to be rotatable within the stator 12 with the rotor shaft 13 as the rotation axis.

[0023] The sealing member 16 seals between the end portion of the rotor shaft 13 that protrudes to the outside through a through hole 15a formed in the housing 15 and the housing 15, and prevents the leakage of the refrigerant R from the inside of the housing 15 to the outside.

[0024] Furthermore, the motor 1 has a refrigerant supply passage 18 that supplies refrigerant R supplied from the refrigerant circulation system 8 to the bearing 20, and a refrigerant discharge passage 19 that returns the refrigerant R from inside the motor 1 to the refrigerant circulation system 8. Specifically, the refrigerant supply passage 18 supplies refrigerant R to the gap between the rotor shaft 13 and the bearing 20. As a result, the refrigerant R is supplied to the sliding surface of the bearing 20 relative to the rotor shaft 13 and used for lubrication of the bearing 20. In this embodiment, refrigerant R, which is a high-pressure supercritical fluid, is used as a lubricant for the bearing 20. The refrigerant R used as a lubricant exits the bearing 20 and enters the housing 15, vaporizes through heat exchange with motor components, and then returns to the refrigerant circulation system 8 through the refrigerant discharge passage 19.

[0025] Motor 1 is an ultra-high-speed rotating motor, configured to operate at high rotational speeds exceeding, for example, 30,000 rpm. Therefore, if a rolling bearing were to be used for bearing 20, rolling fatigue would become a problem. Furthermore, if a typical oil-lubricated sliding bearing using oil were to be used, the loss due to oil stirring resistance by the rotor shaft 13 would be significant. Therefore, in this embodiment, a sliding bearing using a supercritical fluid refrigerant R, which has significantly lower viscosity than oil, is used as bearing 20 instead of oil. In this embodiment, by supplying a supercritical fluid refrigerant R, which has higher density and viscosity than gaseous refrigerant R, to bearing 20, a necessary liquid film can be provided on the sliding surface. This eliminates problems such as rolling fatigue and oil stirring resistance.

[0026] [Refrigerant refrigeration cycle] Next, with reference to Figure 2, the refrigeration cycle of the refrigerant R in this embodiment will be described. Figure 2 is a pH diagram of the CO2 refrigerant, with the horizontal axis representing enthalpy and the vertical axis representing pressure. The viscosity (μPa·s) of the CO2 refrigerant is also shown in Figure 2. When the pressure and temperature of the CO2 refrigerant are increased from the ambient environment (room temperature, 1 atmosphere) to reach the critical point (31°C, 7.4 MPa), it becomes a supercritical fluid.

[0027] First, in the refrigeration cycle (ABCD) of this embodiment, a compression stroke (AB) is performed by the compressor 81. The compressor 81 is a rotary type and receives high-temperature, low-pressure CO2 refrigerant R (gas) from the motor 1 via piping 85 (point A), compresses the received refrigerant R, and discharges high-temperature, high-pressure CO2 refrigerant R (supercritical fluid) (point B).

[0028] Next, a condensation process (BC) is performed by the heat exchanger 83. The heat exchanger 83 receives high-temperature, high-pressure CO2 refrigerant R (point B), exchanges heat with the external environment (cold air, cooling water, etc.), and generates medium-temperature, high-pressure CO2 refrigerant R (supercritical fluid) (point C). The medium-temperature, high-pressure CO2 refrigerant R is supplied to the bearing 20 of the motor 1 and lubricates the bearing 20.

[0029] Furthermore, an expansion stroke (CD) takes place inside the motor 1. The CO2 refrigerant R enters the internal space 15b of the housing 15 through the annular support space between the bearing 20 and the rotor shaft 13, and through the injection passage. At this time, the CO2 refrigerant R expands as it moves from a narrow space to a wider space, becoming a low-temperature, low-pressure CO2 refrigerant R (gas-liquid mixture) (point D). Furthermore, an evaporation stroke (DA) takes place inside the motor 1. The low-temperature, low-pressure CO2 refrigerant R evaporates within the housing 15 by exchanging heat with the high-temperature part of the motor 1, becoming a high-temperature, low-pressure CO2 refrigerant R (gas). This high-temperature, low-pressure CO2 refrigerant R is returned to the compressor 81 (point A).

[0030] [Bearing structure] Figures 3 and 4 are explanatory diagrams of the bearing structure of this embodiment. Figure 3 shows a radial cross-section of the bearing 20, and Figure 4 shows the bearing 20 viewed from the rotor 11 along the axial direction L. As shown in Figure 3, the bearing 20 rotatably supports the end of the rotor shaft 13. The bearing 20 is a substantially cylindrical member and has an outer circumferential surface 21, a sliding surface (inner circumferential surface) 22 with respect to the rotor shaft 13, and a thrust surface (rotor end surface) 24 facing the rotor 11. The rotor shaft 13 has a main portion 13a to which the rotor 11 is attached, and a support portion 13b supported by the bearing 20. The diameter of the support portion 13b is smaller than the diameter of the main portion 13a. Therefore, an annular sliding surface 13c is provided in the stepped portion between the main portion 13a and the support portion 13b. The sliding surface 13c of the rotor shaft 13 and the thrust surface 24 of the bearing 20 are perpendicular to the axial direction L so that they can slide against each other.

[0031] Furthermore, the bearing 20 has a through hole 23 that extends radially from the outer circumferential surface 21 through the side wall and communicates with the sliding surface 22. The through hole 23 communicates with the refrigerant supply passage 18 and forms part of the refrigerant supply passage 18. The refrigerant supply passage 18 may also be directly connected to the support space 22a between the rotor shaft 13 and the bearing 20 without passing through the through hole 23.

[0032] Furthermore, the bearing 20 and the housing 15 have injection passages 32 formed therein, extending from the support space 22a of the bearing 20 to the internal space 15b of the housing 15. The injection passages 32 have a communication hole 32a formed in the bearing 20 and a communication hole 32b formed in the housing 15. The communication hole 32a extends from the sliding surface 22 through the side wall of the bearing 20 to the outer circumferential surface 21. The communication hole 32b communicates with the communication hole 32a and extends to an opening 32c that opens into the internal space 15b. The injection passages 32 extend linearly or curvilinearly obliquely with respect to the axial direction L such that the coil end 12c is located on the extension of their path. The injection passages 32 define the injection direction and also function as expansion valves.

[0033] As shown in Figure 4, when viewing the bearing 20 from the axial direction L, multiple (12 in Figure 4) openings 32c are arranged at equal intervals in the circumferential direction on the thrust surface 24 of the bearing 20. In this embodiment, the coolant R is injected from the multiple openings 32c toward the coil end 12c. Note that at least one opening 32c is sufficient. However, in order to allow the stator 12 to be cooled uniformly in the circumferential direction, it is preferable to arrange multiple openings 32c at equal intervals in the circumferential direction.

[0034] Figure 5 shows a modified example of the bearing 20. Figure 5 is an alternative example in which the injection passage 32 does not include the communication hole 32b formed in the housing 15. In this example, the thrust surface 24 of the bearing 20 is larger in diameter than in the embodiment of Figure 3. In this case, the injection passage 32 consists only of the communication hole 32a formed in the bearing 20, and the opening 32c is formed on the thrust surface 24 of the bearing 20.

[0035] During operation of motor 1, the refrigerant circulation system 8 pumps the supercritical fluid refrigerant R to the bearing 20 through the refrigerant supply passage 18 and through-hole 23. The supercritical fluid refrigerant R maintains a high-pressure state and lubricates the bearing 20 by filling the support space 22a between the rotor shaft 13 and the bearing 20. The refrigerant R flows axially L through the narrow support space 22a and is then injected into the internal space 15b of the housing 15 through the narrow injection passage 32. The refrigerant R expands as it enters the wider internal space 15b of the housing 15, becoming a gas-liquid mixture. The expanded refrigerant R is directed by the injection passage 32 and guided to the coil end 12c. Upon reaching the coil end 12c, the refrigerant R cools the coil end 12c. The refrigerant R that has vaporized after heat exchange with the coil end 12c is discharged to the outside through the refrigerant discharge passage 19.

[0036] [Flow rate adjustment control] Next, with reference to Figure 6, an embodiment of flow rate adjustment control for the refrigerant R that cools the coil ends 12c of the stator 12 will be described. In Figure 6, the non-output ends of the rotor shaft 13 that are not connected to external structures (such as transaxles) are shown, but a similar configuration is provided at the output end.

[0037] In this embodiment, power to support the rotor shaft 13 can be obtained by supplying a supercritical fluid refrigerant R to the bearing 20. However, if the refrigerant R vaporizes in the bearing 20, the desired density and viscosity cannot be secured, leading to increased frictional resistance and wear. Furthermore, if the flow rate of the refrigerant R ejected from the bearing 20 into the internal space 15b of the housing 15 is large, the refrigerant R that does not vaporize completely will be supplied to the downstream compressor 81, causing liquid compression. In addition, the cooling requirements for the coil ends 12c differ depending on the operating state of the motor 1. For this reason, in this embodiment, the flow rate of the refrigerant R ejected from the bearing 20 into the internal space 15b of the housing 15 is appropriately controlled.

[0038] In Figure 6, the flow rate of the refrigerant R supplied to the bearing 20 is adjusted by the flow rate adjustment unit 40. For this flow rate adjustment control, the flow rate adjustment unit 40 includes a flow rate adjustment valve 41 provided in the refrigerant supply passage 18 and a controller 42 that controls the flow rate adjustment valve 41. The controller 42 is a computer with a processor, etc., which receives signals from various sensors provided in the motor system S (refrigerant temperature, refrigerant pressure, refrigerant flow rate, motor rotation speed, stator temperature, etc.) and outputs operating signals to each component of the refrigerant circulation system 8, as well as to solenoid valves, electromagnets, etc.

[0039] Based on sensor signals SR such as motor rotation speed, the controller 42 can increase the flow rate by opening the flow control valve 41 when the cooling requirement for the motor 1 is high (for example, when the motor 1 is operating at a high rotation speed), and decrease the flow rate by opening the flow control valve 41 when the cooling requirement is low (for example, when the motor 1 is operating at a low rotation speed). In this embodiment, it is possible to appropriately adjust the injection flow rate from the bearing 20 to the coil end 12c in response to the cooling requirement.

[0040] [Mechanism of Action and Effects] Next, the operation and effects of the motor system S according to this embodiment will be described. The motor system S according to this embodiment includes a stator 12, a rotor 11, a rotor shaft 13 fixed to the rotor 11 and extending in the axial direction L, a sliding bearing 20 that rotatably supports the rotor shaft 13, and a housing 15 that holds the sliding bearing 20. The motor system S further includes a refrigerant supply passage 18 that communicates with the sliding surface 22 of the sliding bearing 20 relative to the rotor shaft 13, passing through at least the housing 15, and an injection passage 32 that penetrates at least the sliding bearing 20 from the sliding surface 22 and has an opening 32c that opens into the internal space 15b of the housing 15. The sliding bearing 20 is configured to be lubricated by a CO2 refrigerant R supplied through the refrigerant supply passage 18 to the support space 22a between the sliding bearing 20 and the rotor shaft 13, and the injection passage 32 is directed to cause the CO2 refrigerant R injected from the injection passage 32 to reach the coil 12b wound around the stator 12.

[0041] In this embodiment, the motor system S can lubricate the sliding surface 22 of the sliding bearing 20 by supplying CO2 refrigerant R to the support space 22a between the sliding bearing 20 and the rotor shaft 13. The motor system S also injects the lubricated CO2 refrigerant R from the support space 22a through the injection passage 32 into the internal space 15b of the housing 15. The injection passage 32 is directed toward the coil 12b of the stator 12, and can cool the coil 12b, which is a high-temperature part of the motor 1. Thus, in this embodiment, the CO2 refrigerant R can be used for both lubrication of the sliding bearing 20 and cooling of the motor 1. Therefore, the motor system S of this embodiment can achieve both a reduction in stirring resistance loss during high-speed rotation and cooling of the coil 12b of the stator 12.

[0042] In this embodiment, the CO2 refrigerant R can be in the form of a supercritical fluid when supplied to the sliding bearing 20. This supercritical fluid expands and displaces into a gas-liquid mixture state when it is ejected from the support space 22a through the injection passage 32 into the housing 15. Furthermore, this gas-liquid mixture evaporates and displaces into a gas by exchanging heat with the coil 12b of the stator 12.

[0043] Furthermore, according to this embodiment, the injection passage 32 extends toward the coil 12b so that the CO2 refrigerant R injected from the injection passage 32 reaches the coil 12b directly. In this embodiment, the CO2 refrigerant R flowing from the support space 22a can be directed by the injection passage 32 and released into the internal space 15b of the housing 15.

[0044] Furthermore, according to this embodiment, the openings 32c of the injection passage 32 are arranged in an annular manner around the rotor shaft 13. In this embodiment, since the CO2 refrigerant R is injected from the multiple openings 32c toward multiple locations on the coil 12b, the coil 12b can be cooled more uniformly in the circumferential direction.

[0045] Furthermore, according to this embodiment, a refrigerant circulation system 8 is provided that supplies CO2 refrigerant R to the refrigerant supply passage 18 and recovers the CO2 refrigerant R from inside the housing 15. In this embodiment, the motor system S, which includes the refrigerant circulation system 8 and the motor 1, can be mounted, for example, on a vehicle.

[0046] Furthermore, according to this embodiment, the refrigerant circulation system 8 includes a compressor 81 that compresses the gaseous CO2 refrigerant R recovered from the housing 15 to produce a supercritical fluid CO2 refrigerant R, and a condenser (heat exchanger) 83 that condenses the CO2 refrigerant R output from the compressor 81, exchanges heat with the external environment, and supplies the supercritical fluid CO2 refrigerant R to the refrigerant supply passage 18. In this embodiment, the gaseous CO2 refrigerant R after heat exchange in the motor 1 is compressed by the compressor 81 to form a high-temperature, high-pressure supercritical fluid (compression stroke). Next, the compressed CO2 refrigerant R is condensed in the condenser 83 to a medium-temperature, high-pressure state (condensation stroke). Furthermore, the condensed CO2 refrigerant R is expanded in the motor 1 to a low-temperature, low-pressure gas-liquid mixture state (expansion stroke). Finally, it is evaporated by heat exchange in the motor 1 to produce a high-temperature, low-pressure gaseous CO2 refrigerant R (evaporation stroke). In this embodiment, a refrigeration cycle can be formed.

[0047] Furthermore, this embodiment includes a flow control valve 41 for adjusting the flow rate of the CO2 refrigerant R flowing through the refrigerant supply passage 18. In this embodiment, by adjusting the opening degree of the flow control valve 41, the flow rate of the CO2 refrigerant R supplied to the sliding bearing 20 can be adjusted, and the injection flow rate of the CO2 refrigerant R released into the internal space 15b of the housing 15 via the sliding bearing 20 can be adjusted.

[0048] Furthermore, according to this embodiment, the refrigerant supply passage 18 is formed to penetrate the sliding bearing 20 and communicate with the sliding surface 22. In this embodiment, for example, a supercritical fluid CO2 refrigerant R can be directly supplied to the sliding surface 22 of the sliding bearing 20 via the refrigerant supply passage 18. [Explanation of symbols]

[0049] 1 motor 11 rotors 12 Stator, 12b Coil, 12c Coil terminal 13 Rotor shaft 15 Housing, 15b Interior space 18 Refrigerant supply passage, 19 Refrigerant discharge passage 20 Bearing, 21 Outer surface, 22 Sliding surface, 22a Support space 23 Through hole, 24 Thrust surface 32 injection passage, 32c opening 40 Flow rate adjustment unit, 41 Flow rate adjustment valve, 42 Controller 8. Refrigerant circulation system 81 Compressor 83 Heat exchanger L axis direction R refrigerant S Motor System

Claims

1. A motor system comprising a stator, a rotor, a rotor shaft fixed to the rotor and extending in the axial direction, a sliding bearing that rotatably supports the rotor shaft, and a housing that holds the sliding bearing, A refrigerant supply passage that communicates with the sliding surface of the sliding bearing relative to the rotor shaft, through at least the housing, An injection passage having an opening that penetrates at least the sliding bearing from the sliding surface and opens into the internal space of the housing, Furthermore, The sliding bearing receives CO2 supplied through the refrigerant supply passage into the support space between the sliding bearing and the rotor shaft. 2 It is configured to be lubricated by a refrigerant. The injection passage receives the CO2 injected from the injection passage. 2 A motor system in which a refrigerant is directed to reach coils wound around the stator.

2. The injection passage receives the CO2 injected from the injection passage. 2 The motor system according to claim 1, wherein the motor extends toward the coil so as to directly deliver the refrigerant to the coil.

3. The motor system according to claim 1, wherein the openings of the injection passage are arranged in a ring shape in the circumferential direction of the rotor shaft.

4. The aforementioned CO 2 The refrigerant is supplied to the refrigerant supply passage, and the CO 2 The motor system according to claim 1, further comprising a refrigerant circulation system for recovering refrigerant from within the housing.

5. The refrigerant circulation system is The CO gas recovered from the housing 2 The refrigerant is compressed to form a supercritical fluid CO 2 A compressor that generates a refrigerant, The CO output from the compressor 2 condenses the refrigerant, exchanges heat with the external environment, and supplies the supercritical fluid CO 2 A condenser that supplies the refrigerant to the refrigerant supply passage, and the motor system according to claim 4.

6. The CO2 flowing through the refrigerant supply passage 2 The motor system according to claim 1, further comprising a flow control valve for adjusting the flow rate of refrigerant.

7. The motor system according to claim 1, wherein the refrigerant supply passage is formed to penetrate the sliding bearing and communicate with the sliding surface.

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