An electric machine and cooling system

Abstract

The application relates to the technical field of vehicles and provides a motor and a cooling system; the motor comprises a shell assembly, a stator assembly, a rotor assembly and a sealing assembly; the stator assembly and the rotor assembly are arranged in the shell assembly; the stator assembly is fixed to the inner surface of the shell assembly; the rotor assembly is rotationally connected to the shell assembly; the sealing assembly divides the inner cavity of the shell assembly into a stator cavity and a rotor cavity; one side of the shell assembly is provided with an air passage buffer cavity; the air passage buffer cavity is communicated with the rotor cavity through an air passage; oil-gas breather valves are arranged at the communication positions of the air passage buffer cavity and the stator cavity; through the oil-gas breather valves, gaseous cooling medium vaporized in the stator cavity passes through the air passage buffer cavity, and liquid cooling medium is prevented from entering the air passage buffer cavity. The application solves the technical problems that the existing motor cannot meet miniaturization and has low heat dissipation efficiency.

Description

Technical Field

[0001] This invention relates to the field of vehicle technology, and more particularly to an electric motor and a cooling system. Background Technology

[0002] In recent years, the market penetration of new energy vehicles has continued to increase. Vehicle manufacturers have placed stringent demands on the power density, peak performance, and lightweight volume of drive motors. Motor miniaturization and high power have become the mainstream development direction in the industry. However, this trend has also led to a significant increase in heat generation per unit volume, making motor heat dissipation a more prominent issue. During motor operation, the winding coils are the main heat source. If the heat generated by the continuous operation of the coils cannot be quickly dissipated, it can easily lead to technical problems such as winding insulation aging, limited peak power of the motor, and thermal degradation. To improve heat dissipation, existing technologies have gradually introduced various immersion cooling structures for motors, which directly immerse the heat-generating components in the cooling medium to increase the heat exchange contact area. However, current conventional immersion cooling solutions generally use ordinary cooling oil or cooling water as the heat exchange medium. Such media rely solely on their own temperature rise to absorb sensible heat to complete heat exchange, resulting in limited heat absorption capacity and low heat exchange rate. The medium maintains a single physical state throughout the process. When faced with high-speed, high-load conditions and short-term concentrated heat generation by the motor, heat dissipation is delayed, and the winding temperature rise suppression effect is poor. It still suffers from technical defects such as insufficient heat dissipation efficiency and the inability of the motor to maintain peak output for extended periods, making it difficult to meet the heat dissipation requirements of current high-power-density miniaturized drive motors. Summary of the Invention

[0003] The purpose of this invention is to provide a motor and a cooling system; this invention solves the technical problems of existing motors being unable to meet miniaturization requirements and having low heat dissipation efficiency. The specific solution is as follows: An electric motor includes: a housing assembly, a stator assembly, a rotor assembly, and a sealing assembly; The stator assembly and the rotor assembly are installed inside the housing assembly; wherein the stator assembly is fixed to the inner surface of the housing assembly; the rotor assembly is arranged inside the hollow stator assembly and is rotatably connected to the housing assembly; The sealing assembly is used to seal and isolate the rotor assembly from the stator assembly, and to divide the inner cavity of the housing assembly into a stator cavity for accommodating the stator assembly and a rotor cavity for accommodating the rotor assembly. A pneumatic buffer chamber communicating with the stator cavity is provided on one side of the housing assembly. The pneumatic buffer chamber is connected to the rotor cavity through a pneumatic passage. An oil and gas vent valve is provided at the connection between the pneumatic buffer chamber and the stator cavity. The oil-gas vent valve allows the vaporized gaseous cooling medium inside the stator cavity to pass through the air passage buffer cavity, while preventing the liquid cooling medium from entering the air passage buffer cavity.

[0004] Optionally, an oil inlet for conveying liquid cooling medium is provided on the middle side wall of the housing assembly, and an air outlet for discharging gaseous cooling medium from the rotor cavity is provided on the side of the housing assembly away from the air passage. Correspondingly, a channel assembly is provided between the housing assembly and the stator assembly; the oil inlet is connected to the stator cavities on both sides of the stator assembly through the channel assembly; The channel assembly includes: an axial channel and several radial channels; The axial channel is arranged around the middle of the outer surface of the stator assembly; Several radial channels are evenly spaced along the circumference on both sides of the axial channel; one end of each radial channel is connected to the axial channel, and the other end is connected to the corresponding stator cavity.

[0005] Optionally, when the temperature of the liquid cooling medium in the stator cavity reaches the vaporization threshold, the liquid cooling medium in the stator cavity vaporizes; After vaporization, the gaseous cooling medium enters the air passage buffer cavity through the oil-gas vent valve, and then enters the rotor cavity through the air passage to cool the rotor assembly. The cooled gaseous cooling medium flows along one side of the rotor cavity, through the gap channel to the other side, and is discharged through the air outlet on the other side of the rotor cavity. A gap channel is formed between the rotor assembly and the stator assembly.

[0006] Optionally, the housing assembly includes: a motor housing, a large end cover, and a small end cover; An oil inlet is provided on the middle side wall of the motor housing; The stator assembly is fixed to the inner surface of the motor housing; and an air duct buffer cavity is provided on one side of the motor housing; the bottom of the air duct buffer cavity has channel openings on both sides that connect to the stator cavity; and an oil and gas vent valve is installed at each of the channel openings. The motor housing has a large end cover and a small end cover sealed at its two ends respectively; correspondingly, both ends of the rotor assembly are rotatably supported by the large end cover and the small end cover via bearings. The large end cap has an air passage inside for connecting the air passage buffer chamber and the rotor chamber; the small end cap has an air outlet and a liquid seal for sealing the rotor assembly on its outer side.

[0007] Optionally, the stator assembly includes: a stator core, an injection-molded body, and a coil; The coil is arranged inside the slot of the stator core; the injection molded body is arranged between the stator core and the coil to provide insulation between the stator core and the coil. The outer surface of the stator core is fitted and fixed to the motor housing, and the outer surface of the stator core is provided with axial and radial channels for the flow of liquid cooling medium; and the interior of the stator cavity contains liquid cooling medium capable of immersing and covering the coil. Both ends of the injection molded body are provided with stop edges on their inner wall surfaces. The stator assembly is axially positioned and sealed at both ends by the stop and sealing components of the injection molded body.

[0008] Optionally, the sealing assembly includes: a front sealing sleeve and a rear sealing sleeve; The outer walls of the front sealing sleeve and the rear sealing sleeve are both fixed to the corresponding stops on both sides of the stator assembly by adhesive bonding.

[0009] Optionally, a liquid level sensor is provided on one side of the stator cavity.

[0010] A cooling system includes the aforementioned motor; it also includes: an axial flow pump, a cooling medium recovery tank, a filter, a delivery oil pump, and a control unit; The control unit is electrically connected to the axial flow pump and the delivery oil pump, respectively. The air outlet is connected to the condenser through an exhaust pipe; wherein, an axial flow pump and a pressure sensor are arranged on the exhaust pipe. The condenser is connected to the cooling medium recovery tank via an intermediate pipe; the cooling medium recovery tank is connected to the delivery oil pump via a first pipe; the delivery oil pump is connected to the oil inlet via a second pipe; wherein, a filter is installed on the first pipe.

[0011] Optionally, the control unit is configured to collect the cooling medium level inside the stator cavity through a liquid level sensor when the vehicle is in a horizontal state, and determine whether the cooling medium level inside the stator cavity is ≤ a preset safe liquid level in the horizontal state. If so, the operating speed of the delivery oil pump is increased so that the level of the cooling medium inside the stator cavity is greater than or equal to the redundant level threshold within a preset time. When the level of the cooling medium inside the stator cavity is greater than or equal to the redundant level threshold, the operating speed of the delivery oil pump is reduced to a set speed. Wherein, the redundant level threshold is greater than the preset safety level.

[0012] Optionally, the control unit is configured to start the axial flow pump on the exhaust pipe when the pressure in the rotor cavity is greater than or equal to a safety pressure setting threshold, to extract the gaseous cooling medium in the rotor cavity and deliver it to the condenser. The control unit is also configured to shut down the axial flow pump on the exhaust pipe when the pressure in the rotor cavity is less than or equal to a preset pressure.

[0013] The beneficial effects of this invention are as follows: This invention provides an electric motor and a cooling system. A sealing assembly divides the inner cavity of the housing assembly into independent stator and rotor cavities. An oil-gas vent valve is installed at the connection between the stator cavity and the air passage buffer cavity, allowing only the vaporized gaseous cooling medium to pass through while preventing the liquid cooling medium from flowing into the air passage buffer cavity. The air passage buffer cavity acts as a pressure buffer, mitigating the back pressure impact generated on one side of the rotor cavity, preventing pressure fluctuations in the downstream air passage and rotor cavity from directly affecting the oil-gas vent valve and causing it to malfunction. It also ensures that vapor is stably delivered to the rotor cavity for rotor cooling, thus addressing the challenges of vehicle bumps and coolant splashing inside the stator cavity at various driving angles. This design prevents liquid phase-change cooling medium from flowing into the air passage, achieving gas-liquid separation and ensuring a stable and reliable phase-change cooling cycle. While meeting the requirements for motor miniaturization, it also improves the overall cooling efficiency of the motor. Attached Figure Description

[0014] Figure 1 This is an exploded structural diagram of an electric motor according to an embodiment of the present invention; Figure 2 A cross-sectional schematic diagram of an electric motor according to one embodiment of the invention; Figure 3 A schematic diagram of a stator assembly according to an embodiment of the invention; Figure 4 A cross-sectional view of a stator assembly according to an embodiment of the invention; Figure 5 A schematic diagram of a rotor assembly according to one embodiment of the invention; Figure 6 A cross-sectional schematic diagram of an electric motor according to one embodiment of the invention; Figure 7 This is a schematic diagram of the flow of cooling medium inside an electric motor according to one embodiment of the invention.

[0015] In the picture: 1. Large end cover; 1.1 Air passage; 2. Rear sealing sleeve; 3. Stator assembly; 3.1 Iron core; 3.2 Injection molded body; 3.3 Coil; 3.4 Stop; 3.11 Axial channel; 3.12 Radial channel; 4. Front sealing sleeve; 5. Rotor assembly; 5.1 Shaft; 5.2 Bearing; 5.3 Balance plate; 5.4 Rotor iron core; 6. Motor housing; 6.1 Oil inlet; 6.2 Channel opening; 6.3 Air passage buffer chamber; 7. Liquid level sensor; 8. Small end cover; 8.1 Air outlet; 9. Liquid seal; 10. Stator cavity; 11. Rotor cavity. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this invention clearer, the following description will be provided in conjunction with the appendix. Figures 1 to 7The present invention will be described in further detail below. It is obvious that the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0017] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” as used in the embodiments of this invention and the appended claims are also intended to include the plural forms, and “multiple” generally includes at least two unless the context clearly indicates otherwise.

[0018] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0019] It should be understood that although the terms first, second, third, etc., may be used in the embodiments of the present invention, these descriptions should not be limited to these terms. These terms are only used to distinguish the descriptions. For example, first may also be referred to as second without departing from the scope of the embodiments of the present invention, and similarly, second may also be referred to as first.

[0020] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or device that includes said element.

[0021] It should be noted that any symbols and / or numbers present in the specification that are not marked in the accompanying drawings are not reference numerals.

[0022] See Figures 1 to 7 The electric motor shown includes: a housing assembly, a stator assembly 3, a rotor assembly 5, and a sealing assembly; The stator assembly 3 and the rotor assembly 5 are installed inside the housing assembly; wherein the stator assembly 3 is fixed to the inner surface of the housing assembly; the rotor assembly 5 is arranged inside the hollow stator assembly 3 and is rotatably connected to the housing assembly. The sealing assembly is used to seal and isolate the rotor assembly 5 from the stator assembly 3, and to divide the inner cavity of the housing assembly into a stator cavity 10 for accommodating the stator assembly 3 and a rotor cavity 11 for accommodating the rotor assembly 5. One side of the housing assembly is provided with an air duct buffer cavity 6.3 that communicates with the stator cavity 10. The air duct buffer cavity 6.3 is connected to the rotor cavity 11 through an air duct 1.1. Oil and gas vent valves are provided at the connection points between the air duct buffer cavity 6.3 and the stator cavity 10. The oil-gas vent valve allows the vaporized gaseous cooling medium inside the stator cavity 10 to pass through the air passage buffer cavity 6.3, while preventing the liquid cooling medium from entering the air passage buffer cavity 6.3.

[0023] Specifically, this invention uses a sealing assembly to divide the inner cavity of the housing assembly into two independent stator cavity 10 and rotor cavity 11. An oil-gas vent valve is installed at the connection point between the stator cavity 10 and the air duct buffer cavity 6.3, allowing only the vaporized gaseous cooling medium to pass through while preventing the liquid cooling medium from flowing into the air duct buffer cavity 6.3. The air duct buffer cavity 6.3 acts as a pressure buffer, mitigating the back pressure impact generated on one side of the rotor cavity 11 and preventing pressure fluctuations in the downstream air duct 1.1 and rotor cavity 11 from directly affecting the oil-gas vent valve and causing it to malfunction. It also ensures that vapor is stably delivered to the rotor cavity 11 to cool the rotor, thus addressing the conditions of vehicle bumps and coolant splashing inside the stator cavity at various driving angles. This design prevents the liquid phase-change cooling medium from flowing into the air duct passage, achieving gas-liquid separation and ensuring a stable and reliable phase-change cooling cycle. While meeting the requirements for motor miniaturization, it also improves the overall cooling efficiency of the motor.

[0024] It is understood that the present invention cools the stator assembly 3 in the stator cavity 10 using a liquid cooling medium, and cools the rotor assembly 5 in the rotor cavity 11 using a phase-change gaseous cooling medium. It should be further noted that under normal operating conditions of long-term heavy load, the hot spot temperature of the coil 3.3 of the stator assembly 3 can approach 150°C, and the steady-state operating temperature of the rotor assembly 5 is approximately 120°C.

[0025] In one specific embodiment, an oil inlet 6.1 for conveying liquid cooling medium is provided on the middle side wall of the housing assembly, and an air outlet 8.1 for discharging gaseous cooling medium from the rotor cavity 11 is provided on the side of the housing assembly away from the air passage 1.1. Correspondingly, a channel assembly is provided between the housing assembly and the stator assembly 3; the oil inlet 6.1 is connected to the stator cavities 10 on both sides of the stator assembly 3 through the channel assembly; The channel assembly includes: an axial channel 3.11 and a plurality of radial channels 3.12; The axial channel 3.11 is arranged around the middle of the outer surface of the stator assembly 3; The axial channel 3.11 has several radial channels 3.12 arranged at intervals along the circumference on both sides; one end of each radial channel 3.12 is connected to the axial channel 3.11, and the other end is connected to the corresponding stator cavity 10.

[0026] Specifically, the stator assembly 3 is provided with a channel assembly consisting of an axial channel 3.11 and multiple radial channels 3.12 on its outer side. The cooling medium is first fed into the annular axial channel 3.11 through the oil inlet 6.1 on the side wall of the housing. The axial channel 3.11 plays a role in uniform flow and buffering. Then, it is delivered to the stator cavities 10 on both sides of the stator assembly 3 through the radial channels 3.12 arranged around it. This allows the liquid cooling medium to be evenly distributed along the circumference of the stator outer ring, avoiding the defects of local high liquid level and uneven medium distribution caused by single-point oil inlet. The decentralized oil supply structure can increase the contact range between the cooling medium and the stator assembly 3, improve the phase change heat absorption cooling effect of the stator coil 3.3, and at the same time, the annular axial channel 3.11 can buffer oil pressure fluctuations, reduce the risk of liquid leakage caused by the medium impacting the oil and gas vent valve, and ensure the stable operation of the entire gas and liquid phase change cooling cycle.

[0027] In one specific embodiment, when the temperature of the liquid cooling medium in the stator cavity 10 reaches the vaporization threshold, the liquid cooling medium in the stator cavity 10 vaporizes. After vaporization, the gaseous cooling medium enters the air passage buffer chamber 6.3 through the oil-gas vent valve, and then enters the rotor cavity 11 through the air passage to cool the rotor assembly 5. The cooled gaseous cooling medium flows along one side of the rotor cavity 11, through the gap channel to the other side, and is discharged through the air outlet 8.1 on the other side of the rotor cavity 11. A gap channel is formed between the rotor assembly 5 and the stator assembly 3.

[0028] It is understood that the liquid cooling medium provided by this invention (e.g., with a boiling point of 70°C) After the insulating fluorinated phase change coolant (within the 80℃ range) reaches the vaporization temperature threshold, it undergoes a phase change to generate a gaseous medium. The gaseous coolant passes through the oil-gas vent valve to block liquid droplets and is then transported to the gas channel buffer chamber 6.3. It then enters one side of the rotor cavity 11 through the gas channel and enters the other side of the rotor cavity 11 along the annular gap channel. Finally, it is discharged outward through the outlet 8.1 on the other side of the rotor cavity 11. The advantages of this design are that the heat absorbed by the phase change vaporization can be efficiently removed from the stator assembly 3. The oil-gas vent valve can prevent the liquid medium from entering the subsequent gas path to avoid liquid leakage failure. The gas channel buffer chamber 6.3 buffers the gas pressure impact. The gap channel between the stator assembly and the rotor assembly 5 can extend the flow path of the gaseous coolant. The airflow can fully cover the rotor assembly 5, bearings and other heat-generating components, increasing the heat exchange time and removing the heat generated by the rotor assembly 5 from all directions. This improves the cooling effect of the rotor assembly 5 and the bearings at both ends, and prevents the bearings from aging and being damaged at high temperatures.

[0029] In one specific embodiment, the housing assembly includes: a motor housing 6, a large end cover 1, and a small end cover 8; An oil inlet 6.1 is provided on the middle side wall of the motor housing 6; The stator assembly 3 is fixed to the inner surface of the motor housing 6; and an air passage buffer cavity 6.3 is provided on one side of the motor housing 6; the bottom of the air passage buffer cavity 6.3 is provided with channel openings 6.2 communicating with the stator cavity 10 on both sides; and an oil and gas vent valve is installed at each of the channel openings 6.2. The motor housing 6 has a large end cover 1 and a small end cover 8 sealed at its two ends respectively; correspondingly, both ends of the rotor assembly 5 are rotatably supported by the large end cover 1 and the small end cover 8 through bearings. The large end cap 1 has an air passage inside for connecting the air passage buffer chamber 6.3 and the rotor chamber 11; the small end cap 8 has an air outlet 8.1 and a liquid seal 9 for sealing the rotor assembly 5 on its outer side.

[0030] In one specific embodiment, the stator assembly 3 includes: a stator core 3.1, an injection-molded body 3.2, and a coil 3.3; The coil 3.3 is arranged inside the slot of the stator core 3.1; the injection molded body 3.2 is arranged between the stator core 3.1 and the coil 3.3 to provide insulation between the stator core 3.1 and the coil 3.3. The outer surface of the stator core 3.1 is fitted and fixed to the motor housing 6, and the outer surface of the stator core 3.1 is provided with an axial channel 3.11 and a radial channel 3.12 for the flow of liquid cooling medium; and the stator cavity 10 has a liquid cooling medium inside that can immerse and cover the coil 3.3. Both ends of the injection-molded body 3.2 are provided with stop edges 3.4 on their inner wall surfaces; The stator assembly 3 is engaged with the sealing component through the stops 3.4 at both ends of the injection-molded body 3.2 to complete the axial positioning and end face sealing of the stator assembly 3.

[0031] It is understood that the present invention achieves insulation and isolation between the coil 3.3 and the stator core 3.1 through the injection-molded body 3.2 configured between them, thereby preventing the high temperature generated by the coil 3.3 during operation from being directly conducted to the stator core 3.1, thus playing a role in heat insulation and protection. The stator core 3.1 has axial channels 3.11 and radial channels 3.12 on its outer side, which allows the liquid cooling medium to flow evenly in the outer wall channels, dissipating heat and cooling the stator core 3.1 from the outside. By relying on the stop 3.4 on the inner wall of both ends of the injection-molded body 3.2 and the sealing components to be assembled and cooperate with each other, the axial positioning and fixing of the stator assembly 3 and the sealing of both end faces can be achieved at one time. There is no need to configure multiple positioning parts separately, which simplifies the overall structure. At the same time, the end face seal can separate the stator cavity 10 and the rotor cavity 11, preventing cross-cavity leakage of the phase change cooling medium and ensuring that the liquid cooling medium in the stator cavity 10 can stably soak the coil 3.3, so that the phase change cooling medium can operate reliably.

[0032] In one specific embodiment, the rotor assembly 5 includes: 5.1 a rotating shaft, 5.2 a bearing, 5.3 a balance plate, and 5.4 a rotor core; wherein the rotor core and two balance plates are fixed in the middle of the rotating shaft; bearings are installed at both ends of the rotating shaft.

[0033] In one specific embodiment, the sealing assembly includes: a front sealing sleeve 4 and a rear sealing sleeve 2; The outer walls of the front sealing sleeve 4 and the rear sealing sleeve 2 are both fixed to the corresponding stops 3.4 on both sides of the stator assembly 3 by adhesive bonding.

[0034] In one specific embodiment, a liquid level sensor 7 is provided on one side of the stator cavity 10.

[0035] On the other hand, the present invention provides a cooling system including the aforementioned motor; it also includes: an axial flow pump, a cooling medium recovery tank, a filter, a delivery oil pump, and a control unit; The control unit is electrically connected to the axial flow pump and the delivery oil pump, respectively. The exhaust port 8.1 is connected to the condenser through an exhaust pipe; wherein, an axial flow pump and a pressure sensor are arranged on the exhaust pipe. The condenser is connected to the cooling medium recovery tank via an intermediate pipe; the cooling medium recovery tank is connected to the oil delivery pump via a first pipe; the oil delivery pump is connected to the oil inlet 6.1 via a second pipe; wherein, a filter is installed on the first pipe.

[0036] It is understood that the cooling system provided by the present invention controls the axial flow pump and the delivery oil pump through the control unit. During operation: the high-temperature gaseous cooling medium discharged from the rotor cavity 11 is transported outward through the outlet 8.1 and the exhaust pipe. The pressure sensor monitors the gas pressure in the exhaust pipe (i.e., the gas pressure in the rotor cavity 11) in real time. When the pressure in the rotor cavity 11 exceeds the standard, the axial flow pump can actively extract the gaseous medium and accelerate the gas delivery to the condenser. After the gaseous medium is condensed back into liquid by the condenser, it flows into the cooling medium recovery tank for collection. After the liquid cooling medium is filtered to remove impurities, it is then transported to the oil inlet 6.1 of the motor by the delivery oil pump for recycling. The advantage of this design is that it can control the cooling medium supply speed according to the actual heating conditions of the motor, and continuously ensure the cooling effect of the stator, rotor and bearing parts.

[0037] In one specific embodiment, the control unit is configured to collect the cooling medium level inside the stator cavity 10 through the liquid level sensor 7 when the vehicle is in a horizontal state, and determine whether the cooling medium level inside the stator cavity 10 is ≤ a preset safe liquid level in the horizontal state. If so, the operating speed of the delivery oil pump is increased so that the cooling medium level inside the stator cavity 10 is greater than or equal to the redundant liquid level threshold within a preset time. When the cooling medium level inside the stator cavity 10 is greater than or equal to the redundant liquid level threshold, the operating speed of the delivery oil pump is reduced to the set speed. Wherein, the redundant liquid level threshold is greater than the preset safety liquid level.

[0038] It is understood that this invention uses a position sensor to collect the liquid level of the cooling medium undergoing phase change inside the stator cavity 10 in real time. By configuring a two-level judgment standard of preset safe liquid level and redundant liquid level threshold, the speed of the delivery oil pump is increased to quickly replenish the cooling medium when the liquid level is low. When the liquid level reaches a higher redundant liquid level, the speed of the delivery oil pump is reduced. Compared with the traditional fixed speed oil supply mode, this design can adaptively compensate for the reduction of coolant caused by vehicle bumps and cooling medium vaporization loss, ensuring that the coil 3.3 is always submerged in liquid cooling medium and ensuring that phase change heat dissipation can continue to be effective. At the same time, it will not continuously pump the medium at high speed, avoiding the risk of long-term high speed energy consumption of the delivery oil pump and excessively high liquid level inside the stator cavity 10 causing liquid coolant to break through the oil-gas vent valve and enter the rotor cavity 11. It is suitable for various vibration loss conditions during vehicle operation.

[0039] illustrative The preset safe liquid level is set to 22mm from the bottom of the stator cavity, and the redundant liquid level threshold is set to 30mm; the cooling medium is hydrofluoroether. The vehicle was driving normally and smoothly, and the motor was generating heat. 76 The hydrofluoroether medium with a boiling point of ℃ continues to vaporize and flow to the rotor cavity 11, while the liquid medium inside the stator cavity 10 is slowly consumed, and the liquid level drops to below 22mm (the preset safe liquid level). The control unit immediately increases the speed of the delivery oil pump to accelerate the delivery of coolant; when the liquid level rises to the 30mm redundant liquid level threshold, the controller reduces the delivery oil pump to the normal set speed for low-speed oil supply. In this way, the liquid level is maintained at 22. Within the 30mm range, the coil 3.3 is always immersed in the coolant to ensure phase change heat dissipation. The liquid level will not be too high, preventing the liquid medium from overflowing the gas channel inlet, passing through the oil-gas vent valve and entering the rotor cavity 11. Moreover, the oil pump does not need to run at high speed for a long time, reducing power consumption.

[0040] In one specific embodiment, the control unit is configured to start the axial flow pump on the exhaust pipe when the pressure of the rotor cavity 11 is greater than or equal to the safety pressure setting threshold, so as to extract the gaseous cooling medium in the rotor cavity 11 and deliver it to the condenser. The control unit is further configured to shut down the axial flow pump on the exhaust pipe when the pressure in the rotor cavity 11 is less than or equal to a preset pressure.

[0041] Specifically, the control unit involved in this invention controls the start and stop of the axial flow pump on the exhaust pipe based on the internal air pressure of the rotor cavity 11. When the high-temperature phase change gaseous cooling medium continuously accumulates in the rotor cavity 11, causing the internal pressure of the rotor cavity 11 to reach a safe pressure setting threshold, the axial flow pump is started to extract the gaseous cooling medium inside the rotor cavity 11 and deliver it to the condenser for condensation and pressure relief. This reduces the internal air pressure of the rotor cavity 11, improves the heat exchange conditions of the rotor, and prevents the rotor temperature from rising and damaging the bearings due to excessive pressure in the rotor cavity 11. At the same time, it avoids back pressure in the gas path, ensuring that the phase change vapor generated in the stator cavity 10 can flow smoothly to the rotor cavity 11 for cooling, and avoids the leakage of cooling medium due to continuous high pressure squeezing the sealing components and bearing positions. When the pressure in the rotor cavity 11 drops to the preset pressure, the axial flow pump is shut down, realizing intermittent on-demand exhaust, reducing the power consumption and component wear caused by continuous operation of the axial flow pump, and ensuring stable operation of the phase change cooling cycle.

[0042] Example The safety pressure setting threshold is 0.12 MPa, and the shutdown preset pressure is 0.08 MPa; The motor continues to work, the cooling medium vaporizes, and the gaseous cooling medium enters the rotor cavity 11 through the oil-gas vent valve, the air passage cavity, and the air passage; the rotor cavity pressure gradually increases to 0.12MPa, and the control unit starts the axial flow pump to pump air outward to relieve pressure.

[0043] Without the axial flow pump to relieve pressure, the pressure in the rotor cavity 11 continues to rise. On the one hand, the high-temperature steam in the rotor cavity cannot be discharged in time, the rotor temperature rises, and there is a risk of bearing overheating and burning. On the other hand, a large back pressure is formed in the gas path, which hinders the flow of gaseous cooling medium from the stator side to the rotor cavity 11, reducing the cooling effect of the stator and rotor. The high pressure will also act on the gap between the sealing sleeve and the bearing, causing the cooling medium to leak outward. When the pressure drops back to 0.08MPa, the axial flow pump stops working.

[0044] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

1. An electric motor, characterized in that, include: Housing assembly, stator assembly, rotor assembly and sealing assembly; The stator assembly and the rotor assembly are installed inside the housing assembly; wherein the stator assembly is fixed to the inner surface of the housing assembly; the rotor assembly is arranged inside the hollow stator assembly and is rotatably connected to the housing assembly; The sealing assembly is used to seal and isolate the rotor assembly from the stator assembly, and to divide the inner cavity of the housing assembly into a stator cavity for accommodating the stator assembly and a rotor cavity for accommodating the rotor assembly. A pneumatic buffer chamber communicating with the stator cavity is provided on one side of the housing assembly. The pneumatic buffer chamber is connected to the rotor cavity through a pneumatic passage. An oil and gas vent valve is provided at the connection between the pneumatic buffer chamber and the stator cavity. The oil-gas vent valve allows the vaporized gaseous cooling medium inside the stator cavity to pass through the air passage buffer cavity, while preventing the liquid cooling medium from entering the air passage buffer cavity.

2. The motor according to claim 1, characterized in that, The housing assembly has an oil inlet for conveying liquid cooling medium on the middle side wall, and an air outlet for discharging gaseous cooling medium from the rotor cavity is provided on the side of the housing assembly away from the air passage. Correspondingly, a channel assembly is provided between the housing assembly and the stator assembly; the oil inlet is connected to the stator cavities on both sides of the stator assembly through the channel assembly; The channel assembly includes: an axial channel and several radial channels; The axial channel is arranged around the middle of the outer surface of the stator assembly; Several radial channels are evenly spaced along the circumference on both sides of the axial channel; one end of each radial channel is connected to the axial channel, and the other end is connected to the corresponding stator cavity.

3. The motor according to claim 1, characterized in that, When the temperature of the liquid cooling medium in the stator cavity reaches the vaporization threshold, the liquid cooling medium in the stator cavity vaporizes. After vaporization, the gaseous cooling medium enters the air passage buffer cavity through the oil-gas vent valve, and then enters the rotor cavity through the air passage to cool the rotor assembly. The cooled gaseous cooling medium flows along one side of the rotor cavity, through the gap channel to the other side, and is discharged through the air outlet on the other side of the rotor cavity. A gap channel is formed between the rotor assembly and the stator assembly.

4. The motor according to claim 2, characterized in that, The housing assembly includes: a motor housing, a large end cover, and a small end cover; An oil inlet is provided on the middle side wall of the motor housing; The stator assembly is fixed to the inner surface of the motor housing; and an air duct buffer cavity is provided on one side of the motor housing; the bottom of the air duct buffer cavity has channel openings on both sides that connect to the stator cavity; and an oil and gas vent valve is installed at each of the channel openings. The motor housing has a large end cover and a small end cover sealed at its two ends respectively; correspondingly, both ends of the rotor assembly are rotatably supported by the large end cover and the small end cover via bearings. The large end cap has an air passage inside for connecting the air passage buffer chamber and the rotor chamber; the small end cap has an air outlet and a liquid seal for sealing the rotor assembly on its outer side.

5. The motor according to claim 4, characterized in that, The stator assembly includes: a stator core, an injection-molded body, and a coil; The coil is arranged inside the slot of the stator core; the injection molded body is arranged between the stator core and the coil to provide insulation between the stator core and the coil. The outer surface of the stator core is fitted and fixed to the motor housing, and the outer surface of the stator core is provided with axial and radial channels for the flow of liquid cooling medium; and the interior of the stator cavity contains liquid cooling medium capable of immersing and covering the coil. Both ends of the injection molded body are provided with stop edges on their inner wall surfaces. The stator assembly is axially positioned and sealed at both ends by the stop and sealing components of the injection molded body.

6. The motor according to claim 5, characterized in that, The sealing assembly includes: a front sealing sleeve and a rear sealing sleeve; The outer walls of the front sealing sleeve and the rear sealing sleeve are both fixed to the corresponding stops on both sides of the stator assembly by adhesive bonding.

7. The motor according to claim 1, characterized in that, A liquid level sensor is installed on one side of the stator cavity.

8. A cooling system, characterized in that, The device includes the motor described in any one of claims 1-7; it also includes: an axial flow pump, a cooling medium recovery tank, a filter, a delivery oil pump, and a control unit; The control unit is electrically connected to the axial flow pump and the delivery oil pump, respectively. The air outlet is connected to the condenser through an exhaust pipe; wherein, an axial flow pump and a pressure sensor are arranged on the exhaust pipe. The condenser is connected to the cooling medium recovery tank via an intermediate pipe; the cooling medium recovery tank is connected to the delivery oil pump via a first pipe; the delivery oil pump is connected to the oil inlet via a second pipe; wherein, a filter is installed on the first pipe.

9. The cooling system according to claim 8, characterized in that, The control unit is configured to collect the level of the cooling medium inside the stator cavity through a level sensor when the vehicle is in a horizontal state, and determine whether the level of the cooling medium inside the stator cavity is ≤ a preset safe level in the horizontal state. If so, the operating speed of the delivery oil pump is increased so that the level of the cooling medium inside the stator cavity is greater than or equal to the redundant level threshold within a preset time. When the level of the cooling medium inside the stator cavity is greater than or equal to the redundant level threshold, the operating speed of the delivery oil pump is reduced to the set speed. Wherein, the redundant level threshold is greater than the preset safety level.

10. The cooling system according to claim 8, characterized in that, The control unit is configured to start the axial flow pump on the exhaust pipe when the pressure of the rotor cavity is greater than or equal to the safety pressure setting threshold, to extract the gaseous cooling medium in the rotor cavity and deliver it to the condenser. The control unit is also configured to shut down the axial flow pump on the exhaust pipe when the pressure in the rotor cavity is less than or equal to a preset pressure.

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