Self-circulation motor end wing disc cooling device and method based on two-phase flash evaporation

Abstract

The invention discloses a self-circulation motor end wing disc cooling device based on two-phase flash evaporation, which comprises a stator iron core, a winding, an oil separation ring, an end cover, a cooling wing disc, an oil inlet interface and an oil outlet interface, and is characterized in that the cooling wing disc is coaxially mounted on the inner side of the end cover through a supporting bearing, and the side close to the end part of the stator is a wing-shaped bent surface; the side far away from the stator is an inclined perforated plane; when the motor runs, an alternating magnetic field at the end part of the winding induces eddy current in the wing disc to generate electromagnetic torque to drive the wing disc to rotate, the opening plane axially sucks a cooling medium to a gap between the wing disc and the end part of the winding, and the cooling medium forms a local low-pressure area on the suction surface side to induce flash boiling when flowing through the wing-shaped surface; and the gas-liquid mixture subjected to enhanced heat exchange is thrown to the outer side of the oil separation ring through centrifugal force, is discharged through the oil outlet connector, is condensed and naturally flows back to the oil inlet connector side to form self-circulation. According to the invention, driving, pumping and strengthening are integrated into a single rotating part, and the device has the characteristics of self-adaptive adjustment, high reliability and compact structure.

Description

Technical Field

[0001] This invention relates to the field of motor cooling technology, specifically to a self-circulating cooling device and method that utilizes the leakage magnetic field at the motor's end to drive a rotating airfoil without contact, thereby inducing localized low-pressure flash boiling on the airfoil surface to achieve efficient cooling of the stator end. Background Technology

[0002] Existing high-power-density motor end cooling primarily employs forced oil circulation or spray cooling methods, requiring the installation of independent oil pumps, filters, flow control valves, and shaft seals externally to the motor. Forced circulation of cooling oil is achieved through mechanical pumping. While this solution meets basic cooling requirements, it significantly increases the number of system parts, prolongs assembly time, and raises overall costs. More critically, the shaft seals are prone to wear and aging during long-term operation, with leakage rates increasing exponentially with service time. For explosion-proof motors, shaft seal leakage is a fatal safety hazard, directly leading to motor failure. Furthermore, the oil pump motor consumes a certain proportion of the main unit's rated power, significantly reducing the overall system efficiency.

[0003] In publicly available technologies, some researchers have attempted to use the extension of a motor rotor shaft to drive a fan or oil pump. However, such solutions still face challenges in mechanical connection and dynamic sealing. They require a drive shaft to penetrate the oil chamber, resulting in low reliability of the dynamic sealing structure. Furthermore, when the rotor speed does not match the cooling requirements, a speed reduction mechanism must be added, further increasing the complexity.

[0004] None of the above technologies fully utilize the inherent end leakage magnetic field energy of the motor (this part of the magnetic field is considered "waste energy" in conventional motor design). This invention addresses this technological gap by proposing to couple electromagnetic induction drive, wing pumping effect, and flash phase change enhancement to a single rotating component, completely eliminating the need for external oil pumps and mechanical shaft extensions, and achieving highly reliable, high-efficiency, and adaptive end cooling of the motor. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a cooling device and method for the end vane of a self-circulating motor based on two-phase flash evaporation, which utilizes the leakage magnetic field at the end of the motor for non-contact driving and induces local low-pressure flash boiling through the airfoil surface to achieve efficient cooling of the stator end of the motor.

[0006] The technical solution adopted by the present invention to solve the technical problem is as follows; A self-circulating motor end-plate cooling device based on two-phase flash evaporation includes a stator core, windings, an oil separator ring, a front end cover, two-phase end-plate cooling vanes, an oil inlet port, an oil outlet port, and a rear end cover. The ends of the windings extend from the axial end face of the stator core. The oil separator ring is a thin-walled cylindrical component that abuts against the inner wall of the stator core, completely isolating the rotor-side dry area from the stator-side oil area radially. The front end cover and the rear end cover are respectively sealed to the motor housing and together with the oil separator ring, form an annular cooling cavity containing an electrically insulating cooling medium. At least one cooling vane is provided and coaxially mounted in the annular cooling cavity inside the oil inlet end cover via a support bearing. It can rotate freely around the motor axis and has no mechanical contact with the rotor. The cooling vane is integrally made of conductive metal material, and its surface near the stator end is configured to be continuously arranged along the circumferential direction. The airfoil-shaped curved surface and the side of the airfoil away from the stator are constructed with an opening plane that is inclined relative to the plane of the airfoil. When the motor is running, the alternating magnetic field at the end of the winding passes through the oil separator ring and induces eddy currents in the cooling airfoil. The electromagnetic torque generated by the interaction between the eddy currents and the alternating magnetic field drives the cooling airfoil to rotate. The rotating opening plane axially draws the cooling medium into the narrow gap between the cooling airfoil and the end of the winding. When the drawn-in cooling medium flows through the airfoil-shaped curved surface, a local low-pressure area is generated on the suction side. The static pressure of this low-pressure area is lower than the saturation pressure of the cooling medium at the current temperature, which induces the cooling medium to flash and boil, forming a gas-liquid two-phase flow on the surface of the winding end. The gas-liquid mixture after enhanced heat exchange is thrown to the outside of the oil separator ring under the action of centrifugal force, discharged through the oil outlet, and condensed and naturally flows back to the oil inlet side, forming a self-circulation.

[0007] Furthermore, the outer diameter of the cooling vane is smaller than the outer diameter of the stator core and larger than the outer diameter of the oil separator ring; the cooling vane has sufficient axial thickness to withstand the pressure load of the cooling medium; the airfoil curved surface has an angle of attack and curvature, so that a local low-pressure area is generated on the suction side when the cooling medium flows through it; the opening plane is inclined relative to the cooling vane plane, so that the cooling vane generates an axial suction effect when it rotates.

[0008] Furthermore, the conductive metal material of the cooling vane has sufficient electrical conductivity to generate driving torque and is a non-ferromagnetic material; the oil separator ring is a non-magnetic thin-walled material; the cooling medium in the annular cooling cavity is an electrically insulating liquid, and the system operating pressure is controlled by an external pressure stabilizing device, so that the cooling medium is in a near-saturated state at its operating temperature.

[0009] Furthermore, the support bearing is installed in the bearing housing inside the end of the oil separator ring, with its inner ring fixed to the oil separator ring and its outer ring engaging with the central journal of the cooling vane.

[0010] Furthermore, the support bearing is a bearing resistant to cooling medium corrosion; a sealing structure is provided between the oil separator ring and the end cover, and between the end cover and the housing, to prevent cooling medium leakage and maintain stable pressure inside the cavity; an insulating structure is provided between the oil separator ring and the stator core to ensure sufficient insulation distance between the cooling medium and the winding.

[0011] Furthermore, the sealing structure is an O-ring or a metal gasket; the insulating structure is an insulating gasket or an insulating coating.

[0012] One preferred embodiment of the present invention is as follows: the cooling vane is installed only on the inner side of the oil inlet end cap with the oil inlet port, and the oil outlet port is set on the oil outlet end cap, forming a self-circulating cooling system driven by a single vane and with axial flow.

[0013] A second preferred embodiment of the present invention is provided with an oil inlet on both end caps, and the cooling vanes are installed on the inner side of both end caps. The oil outlet is located in the middle of the housing, forming a self-circulating cooling system driven by dual vanes and radially converging.

[0014] A self-circulating cooling method for the motor end using the cooling device of claim 1 includes the following steps: A. System oil filling and pressure regulation: Before operation, inject electrically insulating cooling medium into the annular cooling cavity through the oil inlet on the end cover, so that the end two-phase cooling vanes, stator winding ends and iron core end faces are completely immersed in the cooling medium, and a gas phase space is reserved in the upper part of the cavity; adjust the initial pressure in the system through the oil tank or pressure stabilizing chamber so that the saturation temperature of the cooling medium at this pressure is slightly lower than the allowable temperature of the motor end; after venting, close the oil filling port to achieve end cavity sealing; B. Electromagnetic induction drive: After the stator winding of the motor is energized, an alternating magnetic field is generated in the end region of the winding. This alternating magnetic field passes through the oil separator ring and induces eddy currents in the cooling vane. The eddy currents interact with the alternating magnetic field to generate electromagnetic torque, which drives the cooling vane to rotate continuously in one direction around the motor axis. C. Cooling medium suction and low-pressure zone formation: The rotating cooling vane accelerates the suction of the cooling medium to the narrow gap between the cooling vane and the winding end through the inclined opening plane. When the cooling medium flows through the curved surface of the airfoil, a local low-pressure zone is formed on the suction side and a high-pressure zone is formed on the pressure side. D. Flash boiling and two-phase flow enhanced heat transfer: When the static pressure value of the local low-pressure area is lower than the saturation pressure of the cooling medium, the cooling medium is induced to flash boil on the surface of the winding end, forming a gas-liquid two-phase flow dominated by small bubbles. The small bubbles rapidly detach from the hot surface under the action of pressure difference and shear force, thereby destroying the wall gas film and significantly improving the boiling heat transfer capacity of the end area. E. Two-phase flow discharge and self-circulation closure: Under the action of centrifugal force, the gas-liquid two-phase flow is thrown to the outside of the oil separator ring, discharged through the oil outlet to the external cooling area for condensation, and then naturally flows back to the oil inlet side along the lower channel of the cavity under the action of gravity and density difference, and is sucked into the cooling vane again to form a closed-loop self-circulation.

[0015] Furthermore, the gas content of the gas-liquid two-phase flow is sufficient to significantly improve the heat transfer coefficient at the winding end, and the driving power consumption of the cooling vane is significantly lower than the operating power consumption of the motor.

[0016] This invention utilizes a three-field coupling effect—electromagnetic induction drive, wing pumping effect, and flash evaporation phase change enhancement—to convert the leakage magnetic field energy at the motor end into efficient cooling capacity, achieving self-circulating cooling of the stator winding end. Its core lies in a single rotating component (cooling vane) simultaneously performing the three functions of drive, pumping, and enhanced heat exchange, completely eliminating the need for external oil pumps and mechanical shaft extensions.

[0017] The innovation of this invention is reflected in the following aspects: I. Electromagnetic induction drive (power source): When the stator windings of the motor are energized, the leakage magnetic field at its ends passes through the non-magnetic oil separator ring and induces eddy currents in the cooling vane made of conductive metal. The interaction between the eddy currents and the alternating magnetic field generates electromagnetic torque, driving the cooling vane to rotate continuously around its axis. The innovation lies in the fact that the driving energy comes from the motor's own end magnetic field, eliminating the need for an external power source, permanent magnets, or mechanical transmission, thus achieving contactless, seal-free, and power-consumption-free power input.

[0018] II. Wing Pumping Effect (Self-Circulating Power): The rotating cooling vane establishes a self-circulating cooling medium through a dual-sided functional structure: 1. Axial suction: The side of the cooling vane away from the stator is an inclined open plane, creating an "axial fan" effect during rotation, accelerating the cooling medium from the end cover side to the narrow gap between the vane and the winding end. 2. Pressure regulation: The side of the vane closer to the stator is an airfoil-shaped curved surface, creating a pressure difference between the flowing medium on both sides: ① Suction side: The fluid accelerates, and the static pressure drops below the saturation pressure; ② Pressure side: The fluid decelerates, and the static pressure rises. The innovation lies in the fact that the pumping capacity automatically adjusts with the rotational speed; the greater the load, the higher the rotational speed, and the stronger the suction, forming an adaptive match.

[0019] III. Enhanced Flash Phase Change (High-Efficiency Heat Exchange): When the local pressure on the suction side of the airfoil surface is lower than the saturation pressure of the cooling medium, the high-temperature liquid on the winding end surface undergoes flash boiling, instantly generating a large number of microbubbles. Under the action of pressure difference and shear force, the bubbles rapidly detach from the hot surface and mix with the surrounding liquid to form a gas-liquid two-phase flow dominated by small bubbles. The innovations are: (1) the bubble impact breaks the vapor film on the wall, maintaining direct contact between the liquid and the metal; (2) the bubble phase interface significantly increases the effective heat transfer area; (3) compared with single-phase flow, the heat transfer capacity is significantly improved.

[0020] IV. Adaptive Adjustment Characteristics: The core advantage of this invention lies in its ability to automatically match cooling intensity with heat load without the need for control circuitry: Increased load leads to increased winding current, enhanced end magnetic field, increased induced torque, increased cooling vane speed, increased pump flow rate, increased pressure drop in the low-pressure zone, enhanced flash evaporation intensity, and improved cooling capacity. Conversely, reduced load results in reverse adjustment of each component, preventing overcooling and energy waste. Within a wide load range, the end temperature rise remains stable, and drive power consumption is consistently maintained at an extremely low level.

[0021] The operational differences between the two arrangement schemes (claims 7 and 8) of this invention: Option 1 (Single-sided vane): A cooling vane is installed only on the oil inlet side end cover. The cooling medium enters from the oil inlet side end cover, is drawn in and flashed by the vane, and then exits from the opposite end of the casing. This option is suitable for motors with a small axial length, resulting in a short flow path and low pressure drop.

[0022] Option 2 (Dual-sided finned discs): A cooling finned disc is installed on each end cover. The cooling medium enters simultaneously from both ends, is drawn in and flashed by the respective finned discs, and then flows out as oil in the middle of the casing. This option is suitable for motors with a large axial length, providing coordinated cooling from both sides with a balanced cooling path.

[0023] This invention achieves integrated driving, pumping, and phase change enhancement through passive coupling of electromagnetic, flow, and thermal fields, completely solving the technical problems of complex structure, low reliability, and inability to adaptively adjust traditional cooling systems.

[0024] The positive and beneficial effects of this invention are as follows: 1. Passive drive: It is driven entirely by the leakage magnetic field induction at the end of the motor, without the need for external oil pumps, shaft seals or independent power supplies, thus completely eliminating the risk of leakage. It is especially suitable for occasions with strict explosion-proof requirements.

[0025] 2. Adaptive adjustment: The cooling capacity automatically increases or decreases with the motor load. The greater the load, the stronger the magnetic field, the higher the speed, the stronger the pumping, and the stronger the flashing, forming a negative feedback closed loop. Stepless matching can be achieved without any control circuit.

[0026] 3. Enhanced heat transfer: The local low pressure induced by the airfoil triggers microbubble flash boiling, which effectively breaks the air film on the wall, significantly increasing the critical heat flux density compared to single-phase flow, allowing the motor to output more power in the same volume.

[0027] 4. High reliability: The rotating part is only a single metal disk, without permanent magnets, windings, or vulnerable mechanical shaft seals. The structure is extremely simple, and the mean time between failures is greatly improved.

[0028] 5. Cost reduction and efficiency improvement: By eliminating traditional auxiliary equipment such as oil pumps, filters, and flow valves, the number of system parts is reduced, the size is reduced, assembly is simplified, the overall cost is reduced, and maintenance requirements are significantly reduced. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure of Scheme 1 (single-sided wing disk) in this invention; Figure 2 for Figure 1 A magnified view of a portion of the image; Figure 3 for Figure 1 A schematic diagram of the structure from another direction (without an inorganic shell); Figure 4 for Figure 3 Schematic diagram of the structure without end caps; Figure 5 for Figure 4 A schematic diagram of the structure in another direction (without windings); Figure 6 for Figure 1 A schematic diagram of the structure from another direction (without end caps, with housing); Figure 7 This is a schematic diagram of the cooling medium flow in Scheme 1 (single-sided wing disk) of the present invention; Figure 8 This is a schematic diagram of the cooling medium flow in Scheme 2 (double-sided wing disk) of the present invention; In the various attached figures: 1--stator core, 2--winding, 3--oil separator ring, 4--front end cover, 5--end two-phase cooling vane, 6--support bearing, 7--annular cooling cavity, 8--oil inlet, 9--casing, 10--oil outlet, 11--rear end cover. Detailed Implementation

[0030] The present invention will be further explained and described below with reference to the accompanying drawings and specific embodiments: Example 1, First Arrangement Scheme (Single-sided wing disc drive, such as...) Figures 1 to 7 (as shown) This embodiment provides an end cooling device for small and medium-sized motors, such as... Figure 1As shown, this device only installs one end two-phase cooling vane 5 in the annular cooling cavity 7 inside the oil inlet end cover. No cooling vane is installed inside the rear end cover 11 on the opposite side. The oil inlet port 8 is located on the front end cover 4 on the oil inlet side, while the oil outlet port 10 is located on the rear end cover 11. The cooling vane 5 is integrally machined from conductive metal. This material has excellent conductivity and is non-ferromagnetic, ensuring effective eddy current induction without interfering with the main magnetic field. The surface of the cooling vane 5 near the stator end is machined with a continuously arranged airfoil-shaped curved surface along the circumferential direction. The cross-sectional profile of this surface references a standard airfoil, and it is designed with an angle of attack and camber, arranged in a radially concentric annular array. The cooling vane 5... The side away from the stator is an inclined plane with holes. This plane is inclined at a certain angle relative to the vane plane and has multiple evenly distributed circular holes. The axis of all holes forms an acute angle with the normal to the vane plane, and the inclination direction is consistent with the vane rotation direction to ensure the best suction effect during rotation. The support bearing 6 is installed in the bearing seat inside the end of the oil separator ring 3. Its inner ring is interference-fitted to the oil separator ring 3, and its outer ring is fitted to the central journal of the cooling vane 5 to achieve rotational support. This bearing has self-lubricating properties and does not require an additional lubrication system. The annular cooling cavity 7 is filled with electrically insulating cooling medium. The system working pressure is controlled within a certain range by the external pressure stabilizing cavity, so that the cooling medium is in a near-saturated state at its working temperature.

[0031] When the motor starts, the leakage magnetic field at the end of the stator winding 2 passes through the oil separator ring 3 and induces eddy currents in the cooling vane 5, generating electromagnetic torque to drive the cooling vane 5 to rotate stably. The rotating inclined opening plane generates an axial suction effect, drawing the cooling medium into the narrow gap between the cooling vane 5 and the end of the winding 2. When the cooling medium flows through the curved surface of the airfoil, a local low-pressure area below the saturation pressure is formed on the suction side, inducing the cooling medium to flash boil on the surface of the end of the winding 2, generating microbubbles, forming a gas-liquid two-phase flow dominated by bubbles, which significantly improves the end heat transfer coefficient.

[0032] After enhanced heat exchange, the gas-liquid mixture is thrown to the outside of the oil separator ring 3 under the action of centrifugal force, and discharged to the external cooler for condensation through the oil outlet 10 at the end of the casing. The cooled liquid flows back naturally to the side of the oil inlet 8 along the lower channel of the cavity under the action of gravity and density difference, and is sucked into the cooling vane 5 again, forming a closed-loop self-circulating circuit, without the need for an external oil pump to provide driving force throughout the process.

[0033] Example 2, Second Arrangement Scheme (Dual-sided wing disc drive, such as...) Figure 8 (As shown) This embodiment provides an end cooling device for a high-power motor. A two-phase cooling vane is installed in each of the annular cooling cavities inside the end caps at both ends. The structural parameters of the two cooling vanes are basically the same as in Embodiment 1, and the similarities will not be repeated. The difference lies in that: the oil inlet ports 8 are respectively located on the end caps at both ends of the housing, serving as inlets for the cooling medium on both sides, while the oil outlet port 10 is located in the middle of the housing 9, serving as the total outlet for the cooling medium; the two cooling vanes can work independently or collaboratively, each drawing cooling medium from the corresponding oil inlet port 8, forming flash evaporation-enhanced heat transfer in their respective winding end regions; the gas-liquid two-phase flow is thrown to the outside of the oil separator ring under centrifugal force, then flows axially towards the middle of the housing, finally being discharged from the total oil outlet port 10 in the middle of the housing to the external cooling system.

[0034] This embodiment effectively shortens the flow path length on one side and reduces pressure drop along the flow path through a symmetrical arrangement on both sides, making it particularly suitable for motors with large axial dimensions and high heat flux density. The rotation directions of the cooling vanes on both sides can be designed to be opposite to each other to balance the axial force and improve bearing life.

[0035] Example 3: Support bearing and sealing insulation structure: The support bearing 6 is preferably a ceramic ball bearing. Its inner ring is interference-fitted with the bearing housing of the oil separator ring 3, and its outer ring is transition-fitted with the central journal of the cooling vane 5. The bearing is lubricated by the self-lubricating cooling medium, requiring no additional oil lubrication system, and is suitable for high-speed rotation conditions. Fluororubber O-rings are used for the sealing structures between the oil separator ring 3 and the end cover, and between the end cover and the housing 9. The compression is controlled within a reasonable range to ensure reliable sealing performance during long-term operation and prevent cooling medium leakage. The insulation structure between the oil separator ring 3 and the stator core 1 is formed by spraying a polyimide coating of a certain thickness to ensure that the insulation distance between the cooling medium and the winding meets the requirements, and the partial discharge intensity is lower than the specified value, meeting the insulation requirements of the high-voltage motor.

[0036] Example 4: Optimization of cooling vane structure parameters: The cross-sectional profile of the curved surface of the airfoil has an appropriate curvature and angle of attack (preferably NACA series airfoils, such as the NACA2412 airfoil), and multiple concentric rings are arranged radially along the cooling vane, with the chord length decreasing from the outside to the inside to accommodate the linear velocity differences at different radii. The holes on the perforated plane are preferably circular, with their centers evenly distributed in a concentric ring on the cooling vane. The hole axes form an acute angle with the normal to the cooling vane plane, and the inclination direction of all holes is consistent with the rotation direction of the cooling vane, ensuring maximum axial suction efficiency. By optimizing the above geometric parameters, pumping head increase and precise control of the low-pressure zone can be achieved within the cooling vane rotation speed range, ensuring that flash boiling occurs under optimal operating conditions.

[0037] The above are merely preferred embodiments of the present invention and do not limit the implementation methods and scope of protection of the present invention. For those skilled in the art, any modifications, equivalent substitutions, or improvements made without departing from the principles of the present invention should be included within the scope of protection defined by the claims of the present invention. The present invention innovatively couples electromagnetic induction drive, wing pumping effect, and flash phase change enhancement to a single rotating component, achieving passive, efficient, and adaptive adjustment of motor end-cooling, and possesses outstanding industrial application value.

Claims

1. A self-circulating motor end vane cooling device based on two-phase flash evaporation, characterized in that: It includes a stator core (1), windings (2), an oil separator ring (3), a front end cover (4), an end two-phase cooling vane (5), an oil inlet (8), an oil outlet (10), and a rear end cover (11); the end of the windings (2) extends from the axial end face of the stator core (1); the oil separator ring (3) is a thin-walled cylindrical piece that is attached to the inner wall of the stator core (1) to completely isolate the dry area on the rotor side from the oil area on the stator side in the radial direction; the front end cover (4) and the rear end cover (11) are respectively sealed to the housing (9) and together with the oil separator ring (3) form an annular cooling cavity (7) for containing electrically insulating cooling medium. At least one cooling vane (5) is provided and is coaxially mounted in the annular cooling cavity (7) inside the oil inlet end cover via a support bearing (6). It can rotate freely around the motor axis and has no mechanical contact with the rotor. The cooling vane (5) is integrally made of conductive metal material. Its surface near the stator end is constructed as an airfoil-shaped curved surface continuously arranged in the circumferential direction, and its surface away from the stator is constructed as an open plane inclined relative to the vane plane. When the motor is running, the alternating magnetic field at the end of the winding (2) passes through the oil separator ring (3) and induces eddy currents in the cooling vane (5). The electromagnetic torque generated by the interaction between the eddy currents and the alternating magnetic field drives the cooling vane (5) to rotate. The rotating open plane axially draws the cooling medium into the narrow gap between the cooling vane (5) and the end of the winding (2). When the drawn-in cooling medium flows through the curved surface of the airfoil, a local low-pressure area is generated on the suction side. The static pressure of this low-pressure area is lower than the saturation pressure of the cooling medium at the current temperature, which induces the cooling medium to flash and boil. A gas-liquid two-phase flow is formed on the surface of the end of the winding (2). The gas-liquid mixture after enhanced heat exchange is thrown to the outside of the oil separator ring (3) under the action of centrifugal force, discharged through the oil outlet (10), and condensed and naturally flowed back to the oil inlet (8) side, forming a self-circulation.

2. The self-circulating motor end vane cooling device based on two-phase flash evaporation according to claim 1, characterized in that: The outer diameter of the cooling fin disk (5) is smaller than the outer diameter of the stator core (1) and larger than the outer diameter of the oil separator ring (3); the cooling fin disk (5) has sufficient axial thickness to withstand the pressure load of the cooling medium; the airfoil curved surface has an angle of attack and curvature, so that a local low-pressure area is generated on the suction side when the cooling medium flows through it; the opening plane is inclined relative to the plane of the cooling fin disk (5), so that the cooling fin disk (5) generates an axial suction effect when it rotates.

3. The self-circulating motor end vane cooling device based on two-phase flash evaporation according to claim 1, characterized in that: The conductive metal material of the cooling vane (5) has sufficient electrical conductivity to generate driving torque and is a non-ferromagnetic material; the oil separator ring (3) is a non-magnetic thin-walled material; the cooling medium in the annular cooling cavity (7) is an electrically insulating liquid, and the system working pressure is controlled by an external pressure stabilizing device, so that the cooling medium is in a near-saturated state at its working temperature.

4. The self-circulating motor end vane cooling device based on two-phase flash evaporation according to claim 1, characterized in that: The support bearing (6) is installed in the bearing seat inside the end of the oil separator ring (3), with its inner ring fixed to the oil separator ring (3) and its outer ring engaged with the central journal of the cooling vane (5).

5. The self-circulating motor end vane cooling device based on two-phase flash evaporation according to claim 1, characterized in that: The support bearing (6) is a bearing resistant to cooling medium corrosion; the oil separator (3) and the end cover, as well as the end cover and the housing (9) are provided with sealing structures to prevent cooling medium leakage and maintain stable pressure in the cavity; the oil separator (3) and the stator core (1) are provided with an insulating structure to ensure that there is sufficient insulation distance between the cooling medium and the winding (2).

6. The self-circulating motor end vane cooling device based on two-phase flash evaporation according to claim 5, characterized in that: The sealing structure is an O-ring or a metal gasket; the insulation structure is an insulating gasket or an insulating coating.

7. The self-circulating motor end vane cooling device based on two-phase flash evaporation according to any one of claims 1 to 6, characterized in that: The cooling vane (5) is installed only on the inner side of the oil inlet end cap with the oil inlet port (8), and the oil outlet port (10) is set on the oil outlet end cap, forming a self-circulating cooling system driven by a single vane and with axial flow.

8. The self-circulating motor end vane cooling device based on two-phase flash evaporation according to any one of claims 1 to 6, characterized in that: An oil inlet (8) is provided on both end caps, and a cooling vane (5) is installed on the inner side of both end caps. The oil outlet (10) is located in the middle of the housing (9), forming a self-circulating cooling system driven by dual vanes and radially converging.

9. A method for self-circulating cooling of the motor end using the cooling device of claim 1, characterized in that, Includes the following steps: A. System oil filling and pressure regulation: Before operation, inject electrically insulating cooling medium into the annular cooling cavity (7) through the oil inlet (8) on the end cover, so that the end two-phase cooling vanes (5), the stator winding end and the iron core end face are completely immersed in the cooling medium, and a gas phase space is reserved in the upper part of the cavity; adjust the initial pressure in the system through the oil tank or pressure stabilizing cavity so that the saturation temperature of the cooling medium under this pressure is slightly lower than the allowable temperature of the motor end, and close the oil filling port after exhausting to achieve end cavity sealing; B. Electromagnetic induction drive: After the stator winding (2) of the motor is energized, an alternating magnetic field is generated in the winding end area. The alternating magnetic field passes through the oil separator ring (3) and induces eddy currents in the cooling vane (5). The eddy currents interact with the alternating magnetic field to generate electromagnetic torque, which drives the cooling vane (5) to rotate continuously in one direction around the motor axis. C. Cooling medium suction and low pressure zone formation: The rotating cooling vane (5) accelerates the suction of the cooling medium to the narrow gap between the cooling vane (5) and the end of the winding (2) through the inclined opening plane. When the cooling medium flows through the curved surface of the airfoil, a local low pressure zone is formed on the suction side and a high pressure zone is formed on the pressure side. D. Flash boiling and two-phase flow enhanced heat transfer: When the static pressure value of the local low-pressure area is lower than the saturation pressure of the cooling medium, the cooling medium is induced to flash boiling on the end surface of the winding (2), forming a gas-liquid two-phase flow dominated by small bubbles. The small bubbles rapidly detach from the hot surface under the action of pressure difference and shear force, thereby destroying the wall gas film and significantly improving the boiling heat transfer capacity of the end area. E. Two-phase flow discharge and self-circulation closure: Under the action of centrifugal force, the gas-liquid two-phase flow is thrown to the outside of the oil separator ring (3), and discharged to the external cooling area through the oil outlet (10). After condensation, it flows back naturally to the oil inlet (8) side along the lower channel of the cavity under the action of gravity and density difference, and is sucked into the cooling vane (5) again to form a closed-loop self-circulation.

10. The cooling method according to claim 9, characterized in that: The gas content of the gas-liquid two-phase flow is sufficient to significantly improve the heat transfer coefficient at the end of the winding (2), and the driving power consumption of the cooling vane (5) is significantly lower than the operating power consumption of the motor.

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