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 more particularly to a motor system having a bearing portion. [Background technology]

[0002] A conventional technique for cooling the coil ends by injecting oil onto the coil ends wound around the 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 the hollow rotor shaft of the electric motor, and the oil is ejected to the outside of the rotor shaft from through holes formed in the circumferential surface of the rotor shaft. The ejected oil is directed toward the coil ends via a member attached to the rotor shaft, thereby cooling the coil ends.

[0003] In general, the 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] Japanese Patent Application Publication No. 2023-17291 Summary of the Invention [Problem to be solved by the invention]

[0005] Generally, when the rotation speed of an electric motor becomes high (for example, above 30,000 rpm), rolling fatigue becomes a problem for rolling bearings. To avoid this, such ultra-high speed rotation motors may use oil-lubricated sliding bearings instead of rolling bearings. In oil-lubricated sliding bearings, oil is supplied to the sliding bearings. In this case, however, in ultra-high speed rotation motors, the viscosity of the oil causes a problem of stirring resistance loss at high rotation speeds of the rotor shaft.

[0006] The present invention has been made to solve the problems of the conventional technology described above, and aims to provide a motor system that can achieve both reduced agitation resistance loss during high-speed rotation and cooling of the stator coil. [Means for solving the problem]

[0007] In order to achieve the above object, 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 plain bearing rotatably supporting the rotor shaft, and a housing for holding the plain bearing, and further comprises a refrigerant supply passage that passes through at least the housing and communicates with the sliding surface of the plain bearing relative to the rotor shaft, and a spray passage that passes from the sliding surface through at least the plain bearing and has an opening that opens into the internal space of the housing (15), wherein the plain bearing is configured to be lubricated by CO2 refrigerant supplied to the support space between the plain bearing and the rotor shaft through the refrigerant supply passage, and the spray passage is oriented so that the CO2 refrigerant sprayed from the spray passage reaches the coil wound around the stator.

[0008] In the present invention configured as described above, the motor system can lubricate the sliding surfaces of the plain bearing by supplying CO2 refrigerant to the support space between the plain bearing and the rotor shaft. The motor system also ejects the lubricated CO2 refrigerant from the support space through the injection passage into the internal space of the housing. The injection passage is oriented toward the stator coil, allowing it to cool the coil, which is a high-temperature part of the motor. This makes it possible for the present invention to use CO2 refrigerant to both lubricate the plain bearing and cool the motor. Therefore, the motor system of the present invention can simultaneously reduce agitation resistance loss during high-speed rotation and cool the stator coil.

[0009] In the present invention, the CO refrigerant can be a supercritical fluid when supplied to the sliding bearing. This supercritical fluid expands and changes to a gas-liquid mixed state when it is ejected from the support space through the injection passage into the housing. This gas-liquid mixed fluid then evaporates and changes to a gas through heat exchange with the stator coil.

[0010] In the present invention, the spray passage preferably extends toward the coil so that the CO refrigerant sprayed from the spray passage reaches the coil directly. According to the present invention configured in this manner, the CO refrigerant flowing from the support space can be directed by the spray passage and discharged into the interior space of the housing.

[0011] In the present invention, preferably, a plurality of openings of the injection passage are arranged annularly in the circumferential direction of the rotor shaft. According to the present invention configured in this manner, the CO refrigerant is injected from the plurality of openings toward a plurality of locations on the coil, thereby making it possible to cool the coil more evenly in the circumferential direction.

[0012] Preferably, the present invention further includes a refrigerant circulation system that supplies a CO2 refrigerant to the refrigerant supply passage and recovers the CO2 refrigerant from within the housing. According to the present invention configured in this manner, a motor system including the refrigerant circulation system and a motor can be installed in, for example, a vehicle.

[0013] In the present invention, the refrigerant circulation system preferably includes a compressor that compresses the gaseous CO2 refrigerant recovered from the housing to generate a supercritical CO2 refrigerant, and a condenser that condenses the CO2 refrigerant output from the compressor, exchanges heat with the external environment, and supplies the supercritical CO2 refrigerant to the refrigerant supply passage. According to the present invention configured in this manner, the gaseous CO2 refrigerant after heat exchange in the motor is compressed by the compressor to generate a high-temperature, high-pressure supercritical fluid (compression stroke). Next, the compressed CO2 refrigerant is condensed in the condenser to generate a medium-temperature, high-pressure CO2 refrigerant (condensation stroke). The condensed CO2 refrigerant is then expanded in the motor to generate a low-temperature, low-pressure gas-liquid mixture (expansion stroke). Finally, the CO2 refrigerant is evaporated by heat exchange in the motor to generate a high-temperature, low-pressure gaseous CO2 refrigerant (evaporation stroke). This is how the present invention forms a refrigeration cycle.

[0014] Furthermore, the present invention preferably further comprises a flow rate adjustment valve that adjusts the flow rate of CO2 refrigerant flowing through the refrigerant supply passage. According to the present invention configured in this manner, by adjusting the aperture of the flow rate adjustment valve, it is possible to adjust the flow rate of CO2 refrigerant supplied to the plain bearing and to adjust the spray flow rate of CO2 refrigerant released into the internal space of the housing via the plain bearing.

[0015] In the present invention, the refrigerant supply passage is preferably formed so as to pass through the sliding bearing and communicate with the sliding surface. According to the present invention configured in this manner, for example, a supercritical fluid CO refrigerant can be supplied directly 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 can achieve both a reduction in agitation resistance loss during high-speed rotation and cooling of the stator coil. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a schematic configuration diagram of a motor system according to an embodiment of the present invention. [Figure 2]1 is an explanatory diagram of a refrigeration cycle of a refrigerant according to an embodiment of the present invention. [Figure 3] 1 is an explanatory diagram of a bearing according to an embodiment of the present invention. [Figure 4] 1 is an explanatory diagram of a bearing according to an embodiment of the present invention. [Figure 5] FIG. 10 is an explanatory diagram of a bearing according to a modified example of the embodiment of the present invention. [Figure 6] 1 is an explanatory diagram of a bearing according to an embodiment of the present invention. DETAILED DESCRIPTION OF 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, the overall configuration of a motor system according to this embodiment will be described with reference to Fig. 1. Fig. 1 is a schematic configuration diagram of a motor system according to this embodiment. The motor system S shown in Fig. 1 is mounted on a vehicle such as an electric vehicle, and can provide 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 rotational driving force to the vehicle. The refrigerant circulation system 8 is configured to circulate a refrigerant R in a refrigeration cycle to cool the motor 1. That is, in this refrigeration cycle, the expansion stroke and evaporation stroke of the refrigerant R are carried out within the motor 1, and the compression stroke and condensation stroke of the refrigerant R are carried out in the refrigerant circulation system 8. In this embodiment, it is preferable to use a CO2 refrigerant, which is a natural refrigerant, as the refrigerant R. Note that the refrigerant R may also be a mixture of a natural refrigerant and oil at a predetermined mixing ratio.

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

[0021] [Motor configuration] The motor 1 according to this 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 (slide bearings) 20 that rotatably support the rotor shaft 13, a housing 15 that accommodates and supports the rotor 11, stator 12, rotor shaft 13, and bearings 20, and a seal member 16 that seals between the housing 15 and the rotor shaft 13. One end of the rotor shaft 13 is connected to a transaxle (not shown) of the vehicle or the like.

[0022] The stator 12, which has a substantially cylindrical shape, is configured by winding a coil 12b around a stator core 12a. As shown in FIG. 1, the coil 12b is wound around the stator core 12a, so that coil ends 12c protrude 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 seal member 16 seals the gap between the housing 15 and the end of the rotor shaft 13 that protrudes to the outside through a through hole 15a formed in the housing 15, thereby preventing leakage of the refrigerant R from the inside of the housing 15 to the outside.

[0024] The motor 1 also has a refrigerant supply passage 18 that supplies the 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. More specifically, the refrigerant supply passage 18 supplies the 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 is used to lubricate the bearing 20. In this embodiment, the 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 leaves the bearing 20 and enters the housing 15, where it is vaporized by heat exchange with the motor components, and then returns to the refrigerant circulation system 8 through the refrigerant discharge passage 19.

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

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

[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 the high-temperature, high-pressure CO2 refrigerant R (point B) and exchanges heat with the external environment (cold air, cooling water, etc.) to generate a medium-temperature, high-pressure CO2 refrigerant R (supercritical fluid) (point C). The medium-temperature, high-pressure CO2 refrigerant R is supplied to the bearings 20 of the motor 1 to lubricate the bearings 20.

[0029] Furthermore, an expansion stroke (CD) takes place inside the motor 1. The CO2 refrigerant R passes through the annular support space between the bearing 20 and the rotor shaft 13 and the injection passage, and enters the internal space 15b of the housing 15. At this time, the CO2 refrigerant R expands as it moves from the narrow space to the wide 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 parts 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] 3 and 4 are explanatory diagrams of the bearing structure of this embodiment. FIG. 3 shows a radial cross section of the bearing 20, and FIG. 4 shows the bearing 20 viewed from the rotor 11 along the axial direction L. As shown in FIG. 3, the bearing 20 rotatably supports the end of the rotor shaft 13. The bearing 20 is a substantially cylindrical member and includes an outer circumferential surface 21, a sliding surface (inner circumferential surface) 22 with the rotor shaft 13, and a thrust surface (rotor end surface) 24 facing the rotor 11. The rotor shaft 13 includes 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 at a step 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 as to be in sliding contact with each other.

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

[0032] Furthermore, an injection passage 32 is formed in the bearing 20 and the housing 15, connecting the support space 22a of the bearing 20 to the internal space 15b of the housing 15. The injection passage 32 has a communication hole 32a formed in the bearing 20 and a communication hole 32b formed in the housing 15. The communication hole 32a passes through the side wall of the bearing 20 from the sliding surface 22 to the outer peripheral surface 21. The communication hole 32b communicates with the communication hole 32a and leads to an opening 32c that opens into the internal space 15b. The injection passage 32 extends obliquely in a straight line or a curved line with respect to the axial direction L, so that the coil end 12c is located on an extension of the injection passage 32. The injection passage 32 determines the injection direction and also functions as an expansion valve.

[0033] As shown in FIG. 4, when the bearing 20 is viewed from the axial direction L, a plurality of (12 in FIG. 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 refrigerant R is sprayed from the plurality of openings 32c toward the coil ends 12c. Note that at least one opening 32c is sufficient. However, to enable the stator 12 to be cooled evenly in the circumferential direction, it is preferable to arrange the plurality of openings 32c at equal intervals in the circumferential direction.

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

[0035] During operation of the motor 1, the refrigerant circulation system 8 pressure-feeds the supercritical fluid refrigerant R through the refrigerant supply passage 18 and the through-hole 23 to the bearing 20. The supercritical fluid refrigerant R maintains a high pressure state and fills the support space 22a between the rotor shaft 13 and the bearing 20, lubricating the bearing 20. The refrigerant R flows in the axial direction L through the narrow support space 22a and then passes through the narrow injection passage 32 to be injected into the internal space 15b of the housing 15. The refrigerant R expands upon entering the large 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 toward the coil ends 12c. The refrigerant R that reaches the coil ends 12c cools them. The vaporized refrigerant R exchanges heat with the coil ends 12c and is discharged to the outside through the refrigerant discharge passage 19.

[0036] [Flow rate adjustment control] Next, an embodiment of flow rate adjustment control of the refrigerant R that cools the coil ends 12c of the stator 12 will be described with reference to Fig. 6. Fig. 6 shows the non-output end of the rotor shaft 13 that is not connected to an external structure (such as a transaxle), but the output end also has a similar configuration.

[0037] In this embodiment, power to support the rotor shaft 13 can be obtained by supplying the 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 ensured, resulting in 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 has not completely vaporized will be supplied to the downstream compressor 81, causing liquid compression. Furthermore, the cooling requirements for the coil end 12c vary 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] 6, the flow rate of refrigerant R supplied to bearing 20 is adjusted by flow rate adjustment unit 40. To achieve this flow rate adjustment control, flow rate adjustment unit 40 includes a flow rate adjustment valve 41 provided in refrigerant supply passage 18 and a controller 42 that controls flow rate adjustment valve 41. Controller 42 is a computer having a processor or the like, which receives signals (refrigerant temperature, refrigerant pressure, refrigerant flow rate, motor rotation speed, stator temperature, etc.) from various sensors provided in motor system S, and outputs operation signals to each component of refrigerant circulation system 8, solenoid valves, electromagnets (electromagnetic solenoids), etc.

[0039] Based on the sensor signal SR of the motor rotation speed, etc., the controller 42 can increase the flow rate by increasing the opening of the flow rate adjustment valve 41 when the cooling demand for the motor 1 is large (for example, when the motor 1 is operating at a high rotation speed), and can decrease the opening of the flow rate adjustment valve 41 to decrease the flow rate when the cooling demand is small (for example, when the motor 1 is operating at a low rotation speed). As a result, in this embodiment, it is possible to appropriately adjust the injection flow rate from the bearing 20 to the coil end 12c according to the cooling demand.

[0040] [Action and effect] 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 plain bearing 20 that rotatably supports the rotor shaft 13, and a housing 15 that holds the plain bearing 20. The motor system S further includes a refrigerant supply passage 18 that passes through at least the housing 15 and communicates with a sliding surface 22 of the plain bearing 20 relative to the rotor shaft 13, and a spray passage 32 that passes from the sliding surface 22 through at least the plain bearing 20 and has an opening 32c that opens into an internal space 15b of the housing 15. The plain bearing 20 is configured to be lubricated by CO2 refrigerant R supplied to a support space 22a between the plain bearing 20 and the rotor shaft 13 through the refrigerant supply passage 18, and the spray passage 32 is oriented so that the CO2 refrigerant R sprayed from the spray passage 32 reaches the coil 12b wound around the stator 12.

[0041] In this embodiment, the motor system S supplies CO2 refrigerant R to the support space 22a between the plain bearing 20 and the rotor shaft 13, thereby lubricating the sliding surface 22 of the plain bearing 20. The motor system S also sprays the lubricated CO2 refrigerant R from the support space 22a through the spray passage 32 into the internal space 15b of the housing 15. The spray passage 32 is oriented toward the coil 12b of the stator 12, allowing it to cool the coil 12b, which is a high-temperature part of the motor 1. This makes it possible for the CO2 refrigerant R to be used to lubricate the plain bearing 20 and cool the motor 1. Therefore, the motor system S of this embodiment can simultaneously reduce agitation resistance loss during high-speed rotation and cool the coil 12b of the stator 12.

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

[0043] Furthermore, according to this embodiment, the spray passage 32 extends toward the coil 12b so that the CO2 refrigerant R sprayed from the spray 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 spray passage 32 and discharged into the internal space 15b of the housing 15.

[0044] Furthermore, according to this embodiment, a plurality of openings 32c of the spray passage 32 are arranged annularly in the circumferential direction of the rotor shaft 13. In this embodiment, CO2 refrigerant R is sprayed from the plurality of openings 32c toward a plurality of locations on the coil 12b, thereby enabling the coil 12b to be cooled more evenly in the circumferential direction.

[0045] Moreover, according to this embodiment, the system further includes a refrigerant circulation system 8 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 on, for example, a vehicle.

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

[0047] Moreover, according to this embodiment, there is also provided a flow rate adjustment valve 41 that adjusts the flow rate of CO2 refrigerant R flowing through the refrigerant supply passage 18. In this embodiment, by adjusting the aperture of the flow rate adjustment valve 41, it is possible to adjust the flow rate of CO2 refrigerant R supplied to the plain bearing 20 and adjust the injection flow rate of CO2 refrigerant R released into the internal space 15b of the housing 15 via the plain bearing 20.

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

[0049] 1 motor 11 rotor 12 stator, 12b coil, 12c coil end 13 rotor shaft 15 housing, 15b internal space 18 refrigerant supply passage, 19 refrigerant discharge passage 20 bearing, 21 outer peripheral surface, 22 sliding surface, 22a support space 23 through hole, 24 thrust surface 32 injection passage, 32c opening 40 flow rate adjusting section, 41 flow rate adjusting 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 including a stator, a rotor, a rotor shaft fixed to the rotor and extending in an axial direction, a plain bearing that rotatably supports the rotor shaft, and a housing that holds the plain bearing, a refrigerant supply passage that passes through at least the housing and communicates with a sliding surface of the plain bearing relative to the rotor shaft; an injection passage that penetrates at least the sliding bearing from the sliding surface and has an opening that opens into the internal space of the housing; Further provided with The sliding bearing is configured to circulate the CO refrigerant supplied through the refrigerant supply passage to a support space between the sliding bearing and the rotor shaft. 2 configured to be lubricated by a refrigerant; The injection passage is configured to 2 The motor system is configured to direct refrigerant to reach coils wound around the stator.

2. The injection passage is configured to 2 The motor system of claim 1 , wherein the refrigerant extends toward the coils so as to allow the refrigerant to reach the coils directly.

3. The motor system according to claim 1 , wherein a plurality of the openings of the injection passages are arranged annularly in the circumferential direction of the rotor shaft.

4. The CO 2 A refrigerant is supplied to the refrigerant supply passage, and the CO 2 The motor system of claim 1 , further comprising a coolant circulation system that recovers coolant from within the housing.

5. The refrigerant circulation system includes: The CO gas recovered from the housing 2 The refrigerant is compressed to produce the supercritical fluid CO 2 a compressor for generating a refrigerant; The CO output from the compressor 2 The refrigerant is condensed and heat exchanged with the external environment, and the CO 2 The motor system of claim 4 further comprising a condenser that supplies refrigerant to the refrigerant supply passage.

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

7. The motor system according to claim 1 , wherein the refrigerant supply passage is formed so as to pass through the plain bearing and communicate with the sliding surface.

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