Rotary electric machine

Abstract

To provide a rotary electric machine having direct-cooling structure that is capable of ensuring a coolant flow even at a low speed at which a revolving speed of a motor is low, with a simple configuration at a low cost.SOLUTION: A rotary electric machine 50 cooled by a liquid coolant comprises: a rotor 2; a low-speed time first channel 9a formed inside the rotor 2, in which the liquid coolant flows; an oil pump 19 by which the liquid coolant is fed into the low-speed time first channel 9a; and a clutch by which the oil pump 19 is connected with the low-speed time first channel 9a when the number of revolutions of the rotor 2 is a predetermined threshold value or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a rotating electric machine, and more particularly to a rotating electric machine having a rotor in which a cooling passage is formed so that a coolant flows in the longitudinal direction. [Background technology]

[0002] Patent Document 1 states that "the rotating electric machine comprises a rotor, a shaft that passes through the rotor along the rotation axis and is supported by a bearing, a stator that houses the rotor inside, a rotor cover that is attached to the axial end face of the rotor, and a housing that has a flow path for supplying oil to the bearing. The rotor cover forms a concentric gap between itself and the shaft, and has an oil receiving portion that receives oil from the bearing in the gap, and an oil distribution path that communicates with the oil receiving portion to the axial end face of the rotor. The rotating electric machine cools the rotor by supplying oil that has been guided into the gap to the oil distribution path by centrifugal force."

[0003] Patent Document 2 states that "In a twin-rotor motor having an inner rotor and an outer rotor, an oil passage is provided on the outer periphery of the outer rotor. Cooling oil is supplied by being discharged from a supply unit fixed to the case onto the rotating surface of the outer rotor. The cooling oil flows into an oil receiving unit due to the action of centrifugal force, and then flows into the interior through a supply port. After passing through the oil passage, the cooling oil is discharged to the outside through a discharge port. In such a cooling structure, the supply unit discharges the cooling oil in a direction that gives it a speed component along the rotational direction. Furthermore, the discharge unit is provided at a position closer to the center of rotation than the oil passage, and the rotational speed of the cooling oil is reduced before being discharged."

[0004] Patent Document 3 states that "The cooling mechanism uses a cooling medium to cool heat-generating equipment installed in the vehicle. The cooling pipes are filled with the cooling medium and connect the vicinity of the heat-generating equipment to a radiator that cools the cooling medium. The water pump is driven using the rotation of the axle of the electric vehicle, generating a flow of cooling water in the cooling pipes. The electromagnetic clutch connects and disconnects the transmission of the axle rotation to the water pump. The vehicle ECU connects the electromagnetic clutch to drive the water pump when the charging rate of the driving battery is above a predetermined value and there is a request to decelerate the electric vehicle." [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 7243780 [Patent Document 2] Japanese Patent Application Laid-Open No. 2000-358345 [Patent Document 3] Japanese Patent Application Publication No. 2017-77041 Summary of the Invention [Problem to be solved by the invention]

[0006] 2. Description of the Related Art In the fields of industry and mobility, rotating electrical machines such as motors need to cool their stators and rotors, and are provided with a cooling structure for this purpose.

[0007] In industrial applications, there is a demand for smaller motors with higher power density to reduce installation space. In recent years, with the advancement of electrification in mobility, there has been a push to increase the power density of motors for aircraft, which have strict weight restrictions, and then for automobiles.

[0008] Under these circumstances, further improvements in the cooling performance of rotating electrical machines are required in all fields.

[0009] Direct liquid cooling methods such as oil cooling are effective for improving the cooling performance of rotating electrical machines, but the rotor, being a moving part, has the problem that the cooling structure tends to be complicated.

[0010] The following Patent Documents 1 and 2 are known as background art of the present invention.

[0011] Patent document 1 discloses a technology in which cooling oil is supplied to the inside of the motor housing through a bearing from a flow path provided radially within a housing cover at the axial end of a rotating electric machine, and the oil flows radially outward within a radial flow path formed by installing a rotor cover at the rotor end, and then passes through a cooling flow path provided axially within the rotor to directly cool the rotor.

[0012] Patent Document 2 discloses a technology for directly cooling the rotor by providing an oil pan at the end of the rotor, spraying oil from a supply unit toward the oil pan, and guiding the cooling oil in the oil pan into an axial oil passage provided in the rotor.

[0013] Cooling the rotor of a rotating electrical machine involves the following problems.

[0014] As mentioned in Patent Documents 1 and 2, the centrifugal force acting on the radial flow passages of the rotor can be used to circulate the coolant through the cooling passages. This has the advantage of eliminating the need for a separate pump and drive motor for pumping the coolant, simplifying the structure. However, when the rotation speed is slow, the centrifugal force becomes weaker, resulting in a problem of reduced coolant flow rate.

[0015] This is an issue that needs to be resolved particularly when used in a wide operating range from low to high speeds, such as in drive motors for mobility vehicles, or when variable speed operation is required in industrial applications.Mobility applications in particular often require large torque and large current when starting, so ensuring the refrigerant flow rate during low-speed rotation is extremely important.

[0016] Furthermore, Patent Document 3 discloses a control method for an electric vehicle that connects a clutch between the vehicle's drive shaft and the cooling water pump when decelerating, but this technology aims to ensure braking force even when the battery is fully charged, so a different measure is required.

[0017] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a rotating electric machine having a direct cooling structure that is simple and low-cost, and that can ensure a sufficient refrigerant flow rate even when the motor is running at low speeds. [Means for solving the problem]

[0018] The present invention includes multiple means for solving the above-mentioned problems, and one example is a rotating electric machine cooled by a liquid refrigerant, comprising: a rotor; a refrigerant flow path formed within the rotor through which the liquid refrigerant flows; a pump that supplies the liquid refrigerant to the refrigerant flow path; and a clutch that connects the pump and the refrigerant flow path when the rotation speed of the rotor is below a predetermined threshold. [Effects of the Invention]

[0019] According to the present invention, it is possible to ensure a sufficient refrigerant flow rate even when the motor is rotating at a low speed with a simple and low-cost structure. Objects, configurations, and effects other than those described above will become apparent from the following description of the embodiment. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a cross-sectional view illustrating the structure of a rotating electrical machine to which a first embodiment is applied. [Figure 2] FIG. 10 is a cross-sectional view illustrating the structure of a rotating electrical machine to which a second embodiment is applied. [Figure 3] FIG. 10 is a top view illustrating the structure of a rotating electrical machine to which a third embodiment is applied. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, embodiments of the rotating electric machine of the present invention will be described with reference to the drawings. In the drawings used in this specification, identical or similar reference numerals are used to designate identical or corresponding components, and repeated description of these components may be omitted.

[0022] Example 1 A first embodiment of the rotating electrical machine of the present invention will be described with reference to FIG.

[0023] (Configuration of rotating electric machine) A rotating electric machine to which the first embodiment is applied will be described with reference to Fig. 1. Fig. 1 is an explanatory diagram of a rotating electric machine to which the first embodiment is applied.

[0024] The rotating electric machine 50 shown in FIG. 1 has a structure cooled by a liquid refrigerant, and is an inner rotor type rotating electric machine that has a stator 1 having a stator core 7 on the outer diameter side of the rotating electric machine 50, and a rotor 2 having a permanent magnet 4 arranged on the inner diameter side between this stator 1 and an air gap 3.

[0025] The rotor 2 has a rotation axis that is rotated by a shaft 5, and has a plurality of permanent magnets 4 arranged in the circumferential direction. The rotor 2 is also supported by bearings 6 so as to be rotatable.

[0026] A first flow path is formed in the axial direction in the rotor core 8 of the rotor 2, and a second flow path is provided on the vertically upper side as the upstream side of the first flow path, and a third flow path is provided on the vertically lower side as the downstream side of the first flow path.

[0027] Of these, the first low-speed flow path 9a and the first high-speed flow path 9b formed in the rotor core 8 of the rotor 2 are generally formed by punching holes in corresponding positions of electromagnetic steel sheets in advance and then stacking the electromagnetic steel sheets to form the rotor core 8, but this is not limited to this and they can be formed by various methods.

[0028] In the rotor 2 of this embodiment, the first flow path is composed of two types of cooling flow paths: a low-speed first flow path 9a through which the liquid refrigerant is pumped by the oil pump 19 when the rotation speed of the rotor 2 is equal to or lower than a predetermined speed (predetermined threshold), and a high-speed first flow path 9b through which the liquid refrigerant is self-excitedly circulated by a centrifugal pump action utilizing the centrifugal force of the rotor 2 when the rotation speed of the rotor 2 is equal to or higher than the predetermined speed (predetermined threshold). The high-speed first flow path 9b is arranged circumferentially offset from the low-speed first flow path 9a.

[0029] The second flow path is configured with two types of cooling flow paths: a low-speed second flow path 10a connected upstream of the low-speed first flow path 9a, through which the liquid refrigerant is pumped by the oil pump 19 when the rotation speed of the rotor 2 is equal to or lower than a predetermined speed; and a high-speed second flow path 10b connected upstream of the high-speed first flow path 9b, which self-excites the liquid refrigerant to circulate by a centrifugal pump action utilizing the centrifugal force of the rotor 2 when the rotation speed of the rotor 2 is higher than the predetermined speed.

[0030] The third flow path is configured with two types of cooling flow paths: a low-speed third flow path 11a that is connected downstream of the low-speed first flow path 9a and through which the liquid refrigerant is pumped by the oil pump 19 when the rotation speed of the rotor 2 is equal to or lower than a predetermined speed; and a high-speed third flow path 11b that is connected downstream of the high-speed first flow path 9b and which self-excites the liquid refrigerant to circulate by a centrifugal pump action that utilizes the centrifugal force of the rotor 2 when the rotation speed of the rotor 2 is higher than the predetermined speed.

[0031] The first low-speed flow path 9a, the second low-speed flow path 10a, and the third low-speed flow path 11a, which are connected at low speeds, and the first high-speed flow path 9b, the second high-speed flow path 10b, and the third high-speed flow path 11b, which are connected at high speeds, do not need to be in the same number, and can be selected appropriately depending on the specifications of the rotating electric machine 50.

[0032] Furthermore, the first low-speed flow path 9a, the second low-speed flow path 10a, and the third low-speed flow path 11a do not need to be the same in number, and the first high-speed flow path 9b, the second high-speed flow path 10b, and the third high-speed flow path 11b do not need to be the same in number, and these can be selected appropriately depending on the specifications of the rotating electric machine 50.

[0033] First, the configuration of the system relating to the first low-speed flow path 9a, which is the main part of the present invention, will be described below.

[0034] A centrifugal clutch 25 is installed on the upper part of the shaft 5 of the rotating electrical machine 50. The centrifugal clutch 25 connects the oil pump 19 to the second low-speed flow path 10a, the first low-speed flow path 9a, and the third low-speed flow path 11a when the rotation speed of the rotor 2 is equal to or lower than a predetermined threshold, and is configured to switch between connection and disconnection between the drive shaft 24 of the oil pump 19 and the shaft 5 of the rotating electrical machine. The centrifugal clutch 25 includes a clutch housing 21 connected to the shaft 5, a compression spring 22, and a weight shoe 23.

[0035] In this embodiment, the shaft 5 of the rotor 2 and the drive shaft 24 of the oil pump 19 are coaxially arranged via a centrifugal clutch 25 .

[0036] When the rotation speed of the rotor 2 is slow and below a predetermined threshold, the weight shoe 23 of the centrifugal clutch 25 is pressed against the drive shaft 24 of the oil pump 19 by the compression spring 22, and the oil pump 19 is driven by part of the shaft power of the rotating electric machine 50, and the oil in the reservoir 20 is pressurized and pumped into the rotating electric machine 50 by the oil pump 19.

[0037] In this embodiment, the drive shaft 24 of the oil pump 19 is hollow, and cooling oil is fed into it through a central hole 26 provided at the top of the shaft 5. The cooling oil then passes through the second low-speed flow path 10a formed in the radial direction, cools the rotor core 8 of the rotor 2 while passing through the first low-speed flow path 9a formed in the axial direction, and flows out to the bottom of the housing 12 of the rotating electrical machine 50 through the third low-speed flow path 11a also formed in the radial direction. The cooling oil in the housing 12 is discharged from the outlet 14 and returns to the reservoir 20.

[0038] When the rotation speed of the rotor 2 increases and exceeds a predetermined threshold, the centrifugal force acting on the weight shoe 23 overcomes the pressing force of the compression spring 22, causing the weight shoe 23 to separate from the drive shaft 24, cutting off the axial output from the shaft 5 of the electric motor. The threshold rotation speed at which the centrifugal clutch 25 is connected / disconnected is determined by the weight of the weight shoe 23 and the spring strength of the compression spring 22, and is therefore set appropriately depending on the required performance.

[0039] A typical centrifugal clutch used between an engine and a driving wheel such as a tire wheel is in a disengaged state when the engine rotation speed is low and is engaged as the engine rotation speed increases. In contrast, the centrifugal clutch 25 in this embodiment is in an engaged state when the rotation speed of the rotor 2 is equal to or less than a predetermined threshold and is disengaged when the rotation speed exceeds the predetermined threshold, and is configured to perform the disengagement / engagement operation opposite to that of a typical centrifugal clutch.

[0040] Therefore, in this embodiment, when the rotation speed of the rotor 2 increases, a cooling flow path is formed within the rotor 2 to serve as a flow path that connects to the reservoir 20 when the centrifugal clutch 25 is disengaged, and that uses the centrifugal pump action of the flow path to self-excite the refrigerant to flow.The first high-speed flow path 9b, second high-speed flow path 10b, and third high-speed flow path 11b, through which the liquid refrigerant flows self-excitedly using the centrifugal pump action, are provided separately from the first low-speed flow path 9a, etc.

[0041] As a result, when the rotor rotates at a speed higher than a certain threshold, the refrigerant that flows naturally down from the reservoir 20 due to gravity flows into the housing 12 of the rotating electric machine through the inlet 13 and flows down to the upper end of the rotor 2, on the inner diameter side of the upper plate blade 15.

[0042] Furthermore, the refrigerant that flows down flows toward the outer diameter side due to centrifugal force, passes through the second high-speed flow path 10b formed by the upper cover 16 and the upper plate blade 15, and cools the rotor core 8 of the rotor 2 as it flows down the first high-speed flow path 9b that passes axially through the rotor core 8.

[0043] Thereafter, the air passes through the third high-speed flow path 11 b formed by the lower cover 18 and the lower plate blade 17 , flows down to the bottom of the housing 12 , and then flows out from the discharge port 14 .

[0044] As described above, the second high-speed flow path 10b and the third high-speed flow path 11b are radial flow paths, and generate a centrifugal pump action due to centrifugal force as the rotor 2 rotates, so that when the rotation speed is high, the refrigerant can circulate self-excited.

[0045] Next, the effects of this embodiment will be described.

[0046] The rotating electric machine 50 cooled by a liquid refrigerant of the above-mentioned embodiment 1 of the present invention comprises a rotor 2, a first low-speed flow path 9a formed within the rotor 2 and through which the liquid refrigerant flows, an oil pump 19 that supplies the liquid refrigerant to the first low-speed flow path 9a, and a clutch that connects the oil pump 19 to the first low-speed flow path 9a when the rotation speed of the rotor 2 is below a predetermined threshold, the clutch being a centrifugal clutch 25 that connects the oil pump 19 to the first low-speed flow path 9a when the rotation speed is below the predetermined threshold, and the drive shaft 24 of the oil pump 19 is arranged coaxially with the shaft 5 of the rotor 2.

[0047] With the above configuration, even when the rotation speed of rotor 2 is low and the centrifugal pumping action of the cooling flow path cannot be utilized, centrifugal clutch 25 is engaged, and the driving force from shaft 5 of rotating electric machine 50 is used to drive oil pump 19 and pump the refrigerant into rotating electric machine 50, thereby ensuring a sufficient refrigerant flow rate. In particular, when an electric vehicle starts, a large torque is required, which increases the current and the heat generation due to copper loss, so it is effective to be able to ensure a sufficient refrigerant flow rate at low rotation speeds.

[0048] Furthermore, when the rotation speed increases, the centrifugal clutch 25 is disengaged, and power to the oil pump 19 is cut off, so that power is not wasted.

[0049] Furthermore, because the oil pump 19 is driven using the shaft power of the rotating electric machine 50, which is the object to be cooled, there is no need to install a separate dedicated drive motor, simplifying the structure. In addition, the shaft 5 of the rotor 2 and the drive shaft 24 of the oil pump 19 are installed coaxially via the centrifugal clutch 25, so the electric motor, oil pump 19, and centrifugal clutch 25 can be integrated, resulting in a more compact design.

[0050] Furthermore, by further providing the first high-speed flow path 9b, the second high-speed flow path 10b, and the third high-speed flow path 11b formed within the rotor 2 and through which the liquid refrigerant flows self-excited by utilizing the centrifugal pump action, cooling can be performed without using a special drive source during high-speed operation, and it is possible to maintain high cooling efficiency without complicating the structure.

[0051] Many electric vehicle motors have characteristics in which the required torque is smaller at high speeds and copper loss is lower than at low speeds. Therefore, the required refrigerant flow rate may be lower at high speeds than at low speeds. In such cases, the number of high-speed first flow path 9b, high-speed second flow path 10b, and high-speed third flow path 11b, which use centrifugal pump action to circulate the refrigerant, may be reduced or even completely eliminated.

[0052] <Example 2> Second Embodiment A rotating electric machine according to a second embodiment of the present invention will be described with reference to Fig. 2. Fig. 2 is an explanatory diagram of a rotating electric machine to which the second embodiment is applied.

[0053] The rotating electric machine 50A of this embodiment shown in Figure 2 is equipped with a power transmission mechanism 28 such as a gear as a clutch unit 31 that connects the oil pump 19 to the first low-speed flow path 9a when the rotation speed of the rotor 2 is below a predetermined threshold in order to transmit axial power from the shaft 5 of the rotor 2 to the oil pump 19, a clutch 27, a detection unit 29 that detects the rotation speed of the rotor 2 and also at least one of the temperature of the rotor 2, the supplied current, and the torque, and a control unit 30 that connects the oil pump 19 to the first low-speed flow path 9a when the rotation speed detected by the detection unit 29 is below a predetermined threshold, and / or connects the oil pump 19 to the first low-speed flow path 9a when at least one of the temperature of the rotor 2, the supplied current, and the torque is above a threshold.

[0054] The other structures including the cooling structure are the same as those in the first embodiment.

[0055] In a rotating electric machine 50A configured in this manner, the size increases due to the addition of the power transmission mechanism 28, but by using an electromagnetic clutch or the like for the clutch 27, it is possible to perform detailed clutch control according to the operating conditions using one or more state quantities of the rotational speed of the rotor 2, the temperature of the rotating electric machine, the current, or the torque.

[0056] For example, in the case of a drive motor for an electric vehicle, it is sometimes impossible to distinguish between starting and stopping in terms of rotational speed. Therefore, regardless of whether the rotational speed is below a predetermined speed, the magnitude of losses such as copper loss can be estimated from torque and current, and the clutch can be engaged when these exceed a threshold value, thereby enabling control with minimal power loss. It is also possible to more directly engage the clutch 27 and allow a refrigerant to flow for cooling when the temperature of the coil of the stator 1 or the permanent magnet 4 of the rotor 2 exceeds a threshold value that is the design upper limit.

[0057] The other configurations and operations are substantially the same as those of the rotating electrical machine of the first embodiment, and the details are omitted here.

[0058] As in the rotating electric machine of Example 2 of the present invention, the clutch 27 has a detection unit 29 that detects the rotation speed, and a control unit 30 that connects the oil pump 19 to the first low-speed flow path 9a when the rotation speed detected by the detection unit 29 is below a predetermined threshold, thereby achieving almost the same effect as the rotating electric machine of Example 1 described above, i.e., making it possible to easily and reliably ensure cooling performance at low speeds.

[0059] Furthermore, the control unit 30 can also or alternatively connect the oil pump 19 to the first low-speed flow path 9a when at least one of the temperature of the rotor 2, the supplied current, and the torque is above a threshold value, thereby making it possible to supply liquid refrigerant at times when cooling is required even when the speed is not low, thereby making it possible to provide a rotating electric machine with higher cooling performance.

[0060] Example 3 A rotating electric machine according to a third embodiment of the present invention will be described with reference to Fig. 3. Fig. 3 is an explanatory diagram of a rotating electric machine to which the third embodiment is applied.

[0061] In the rotating electric machine of this embodiment shown in Figure 3, the rotor 2A is different from the rotor 2 of the rotating electric machine 50 of embodiment 1 or the rotating electric machine 50A of embodiment 2 in that the first low-speed flow path 9a, through which the refrigerant flows during low-speed rotation, is located on the outer diameter side of the first high-speed flow path 9b, through which the refrigerant flows during high-speed rotation.

[0062] Generally, in an electric vehicle, when the rotation speed is low when starting, a large current is required to generate torque, and heat from the coil of the stator 1 is transmitted through the outer surface of the rotor 2A. For this reason, the first low-speed flow path 9a, through which the refrigerant flows during low-speed rotation, is located on the outer periphery of the permanent magnets 4 of the rotor core 8 of the rotor 2A, to prevent the temperature of the permanent magnets 4, which are sensitive to heat, from rising.

[0063] On the other hand, during high-speed rotation, iron loss due to harmonic components of the magnetic flux increases, so the first high-speed flow path 9b is arranged on the inner diameter side of the rotor core 8 to mainly cool the rotor core 8.

[0064] The other configurations and operations are substantially the same as those of the rotating electric machine 50 of the first embodiment or the rotating electric machine 50A of the second embodiment, and therefore details thereof will be omitted.

[0065] The rotating electric machine according to the third embodiment of the present invention also provides substantially the same effects as the rotating electric machine 50 according to the first embodiment or the rotating electric machine 50A according to the second embodiment.

[0066] Furthermore, within the rotor 2A, the first low-speed flow path 9a is positioned radially outward of the first high-speed flow path 9b, allowing the refrigerant flow path to be located in a position appropriate for the type and location of loss that changes depending on the operating conditions, thereby improving cooling performance regardless of the operating conditions.

[0067] <Other> It should be noted that the present invention is not limited to the above-described embodiment, and includes various modifications. The above-described embodiment has been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to an embodiment having all of the described configurations.

[0068] It is also possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment.It is also possible to add, delete, or replace a part of the configuration of each embodiment with the configuration of another embodiment.

[0069] For example, although the present invention has been described in the embodiment with reference to an inner rotor type rotating electrical machine, it can also be implemented in an outer rotor type rotating electrical machine.

[0070] Furthermore, other embodiments conceivable within the scope of the technical idea of ​​the present invention are also included within the scope of the present invention. [Explanation of symbols]

[0071] 1...Stator 2,2A...Rotor 3...Air gap 4...Permanent magnet 5... Shaft (output shaft) 6...Bearing 7...Stator core 8...Rotor core 9a...First flow path at low speed (refrigerant flow path) 9b...First flow path at high speed (centrifugal pump flow path) 10a...Second flow path at low speed (refrigerant flow path) 10b...Second flow path at high speed (centrifugal pump flow path) 11a...Third flow path at low speed (refrigerant flow path) 11b...Third flow path at high speed (centrifugal pump flow path) 12. Housing 13...Entrance 14...Exhaust port 15...Upper blade 16...Top cover 17...Lower blade 18...Lower cover 19...Oil pump 20...Reservoir 21...Clutch housing 22...Compression spring 23...Weight shoe 24...Drive shaft (drive shaft) 25...Centrifugal clutch (centrifugal type clutch) 26…Center hole 27…Clutch 28...Power transmission mechanism 29...Detection unit 30...Control unit 31...Clutch section 50,50A...Rotating electric machine

Claims

1. A rotating electric machine cooled by a liquid refrigerant, A rotor; a refrigerant flow path formed in the rotor through which the liquid refrigerant flows; a pump for supplying the liquid refrigerant to the refrigerant flow path; a clutch that connects the pump and the refrigerant flow path when the rotation speed of the rotor is equal to or lower than a predetermined threshold value. Rotating electric motor.

2. 2. The rotating electric machine according to claim 1, the clutch is a centrifugal clutch that connects the pump and the refrigerant flow path when the rotation speed is equal to or less than the predetermined threshold value, The drive shaft of the pump is arranged coaxially with the output shaft of the rotor. Rotating electric motor.

3. 2. The rotating electric machine according to claim 1, The clutch has a detection unit that detects the rotation speed, and a control unit that connects the pump and the refrigerant flow path when the rotation speed detected by the detection unit is equal to or less than the predetermined threshold value. Rotating electric motor.

4. 4. The rotating electric machine according to claim 3, The control unit further connects the pump and the refrigerant flow path when at least one of the temperature of the rotor, the supplied current, and the torque is equal to or greater than a threshold value. Rotating electric motor.

5. 2. The rotating electric machine according to claim 1, The rotor further includes a centrifugal pump flow path through which the liquid refrigerant flows in a self-excited manner by utilizing a centrifugal pump action. Rotating electric motor.

6. 6. The rotating electric machine according to claim 5, In the rotor, the refrigerant flow path is disposed on the outer diameter side of the centrifugal pump flow path. Rotating electric motor.

7. A rotating electric machine cooled by a liquid refrigerant, A rotor; a refrigerant flow path formed in the rotor through which the liquid refrigerant flows; a pump for supplying the liquid refrigerant to the refrigerant flow path; a clutch that connects the pump and the refrigerant flow path when the rotation speed of the rotor is equal to or lower than a predetermined threshold value, The clutch has a detection unit that detects at least one of the temperature of the rotor, the supplied current, and the torque, and a control unit that connects the pump and the refrigerant flow path when at least one of the temperature of the rotor, the supplied current, and the torque detected by the detection unit is equal to or lower than the predetermined threshold value. Rotating electric motor.

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