Composite motor cooling system, permanent magnet synchronous motor and vehicle

Abstract

The invention relates to a composite motor cooling system, a permanent magnet synchronous motor and a vehicle. The cooling system comprises a motor shell, a stator, a rotor, a water cooling unit and an oil cooling unit. The water cooling unit is arranged on the motor shell and comprises an outer-layer water path and an inner-layer water path which are arranged along the circumferential direction of the motor shell; the oil cooling unit comprises a heat exchange oil way, a first oil groove, a second oil groove, a center oil way and a radial oil way. The heat exchange oil way is arranged between the outer-layer water way and the inner-layer water way and communicates with the first oil groove and the center oil way. The first oil grooves are circumferentially arranged around the outer diameter of the stator core, and the plurality of second oil grooves are arranged at the axial end parts of the first oil grooves, are communicated with the first oil grooves and are circumferentially arranged; the central oil way is arranged in a main shaft of the rotor in the axial direction, and the radial oil ways are arranged in the circumferential direction of the main shaft, communicate with the central oil way and comprise the first radial oil way used for cooling a bearing, the second radial oil way used for cooling the inner surface of a winding and the third radial oil way used for cooling a rotor iron core.

Description

Technical Field

[0001] The present invention relates to the technical field of motor cooling, and in particular to a composite motor cooling system, a permanent magnet synchronous motor and a vehicle. Background Art

[0002] During the operation of the motor, due to the continuous increase in winding current density and overall power density requirements, the motor structure is becoming more and more compact, which leads to a rapid increase in the motor winding temperature and operating temperature. The temperature increase will bring many negative effects: on the one hand, the resistivity of the stator winding will gradually increase, resulting in increased motor losses; on the other hand, the winding insulation layer will fail, resulting in a short circuit between the wires, which will put the motor at risk of breakdown; at the same time, once the permanent magnet temperature exceeds the allowable temperature range, demagnetization will occur. Therefore, effective heat dissipation and cooling of the permanent magnet synchronous motor and controlling the temperature of each motor component within a safe range have become a technical problem that needs to be solved urgently.

[0003] At present, the end windings of stator oil-immersed cooling motors are usually cooled by completely immersing them in oil or by installing an oil spray ring on the top. However, these cooling methods have obvious shortcomings: in the complete immersion method, due to the small end space, the cooling oil flows slowly in the cavity, and the convective heat transfer at the fluid-solid interface is poor, resulting in the end windings not being fully cooled; in the top oil spray method, the cooling medium can only contact the outer surface of the end windings, and the inner side and central part of the end windings, where the heat dissipation is even worse, are difficult to be effectively cooled.

[0004] Some improvement schemes have also appeared in the prior art, such as using a special winding oil injection ring structure to improve the cooling effect of the end winding by setting circumferential and axial oil injection holes on the side of the oil injection teeth. However, this structural design will inevitably lead to an increase in the size of the stator winding end, thereby increasing the axial size of the motor and the weight of the whole machine, which is contrary to the development requirements of miniaturization and high power density of motors.

[0005] Therefore, how to achieve effective cooling of the inner and outer surfaces of the motor stator winding ends without increasing the axial size of the motor while improving the heat exchange efficiency has become a technical problem that needs to be urgently solved in this field. Summary of the invention

[0006] The invention discloses a composite motor cooling system, a permanent magnet synchronous motor and a vehicle, aiming to solve the technical problems existing in the prior art.

[0007] The present invention adopts the following technical solutions: On the one hand, an embodiment of the present invention provides a composite motor cooling system, including a motor housing, a stator, a rotor, a water cooling unit and an oil cooling unit, wherein end covers are provided at both ends of the motor housing, and the stator and the rotor are encapsulated in the motor housing; The water cooling unit is arranged on the motor housing, and comprises an outer water channel and an inner water channel arranged along the circumference of the motor housing; The oil cooling unit is arranged in the motor housing, the stator and the rotor, and includes a heat exchange oil circuit, a first oil tank, a second oil tank, a central oil circuit and a radial oil circuit; The heat exchange oil circuit is arranged between the outer water circuit and the inner water circuit, and the heat exchange oil circuit is respectively connected with the first oil tank and the central oil circuit; The first oil groove is arranged circumferentially along the outer diameter of the stator core of the stator, and a plurality of second oil grooves are arranged at the axial ends of the first oil groove and arranged circumferentially, and the second oil grooves are connected to the first oil grooves; The central oil circuit is axially arranged in the main shaft of the rotor, and a plurality of radial oil circuits are arranged circumferentially along the main shaft and connected to the central oil circuit. The radial oil circuits include a first radial oil circuit for cooling the bearings, a second radial oil circuit for cooling the inner surface of the winding, and a third radial oil circuit for cooling the rotor core.

[0008] As a preferred technical solution, the outer water channel and the inner water channel are arranged in a U shape and are connected to each other. The motor housing is provided with a water inlet and a water outlet, and the water inlet and the water outlet are connected to the outer water channel and the inner water channel.

[0009] As a preferred technical solution, the heat exchange oil circuit is arranged in a U shape, the motor housing is provided with an oil inlet and an oil outlet, and the oil inlet is connected to the heat exchange oil circuit; The oil cooling unit further comprises an end cover oil circuit arranged on the end cover, an oil cavity arranged inside the motor housing, a first housing oil circuit cavity and a second housing oil circuit cavity arranged on the inner wall of the motor housing; The heat exchange oil circuit is connected to the first shell oil circuit cavity through the first connecting passage, and the heat exchange oil circuit is connected to the second shell oil circuit cavity through the second connecting passage. The second shell oil circuit cavity extends axially and is connected to the end cover oil circuit; The oil chamber is connected with the oil outlet and is used for collecting the return oil.

[0010] As a preferred technical solution, multiple groups of outer water channels and inner water channels are provided along the circumference of the motor housing, and two groups of water channels adjacent to each other in the circumferential direction are connected through a connecting section; A plurality of heat exchange oil paths are provided along the circumference of the motor housing, and each group of heat exchange oil paths is correspondingly arranged between a group of outer water paths and a group of inner water paths.

[0011] As a preferred technical solution, the first oil groove is arranged at the middle position of the outer diameter of the stator core, and the first oil groove is connected to the oil path cavity of the first housing.

[0012] As a preferred technical solution, the second oil groove includes a first group of sub-oil grooves and a second group of sub-oil grooves, both of which are evenly arranged along the circumference of the stator core; The first group of sub-oil grooves extend axially, the second group of sub-oil grooves extend obliquely at a first preset angle, and the second group of sub-oil grooves penetrate the stator core and are used to spray cooling medium onto the outer surface of the end of the stator winding.

[0013] As a preferred technical solution, the first preset angle is matched with the end height of the stator winding and / or the pressure of the cooling medium, so as to enable the cooling medium to be sprayed onto the end outer surface of the stator winding along a predetermined trajectory.

[0014] As a preferred technical solution, the oil cooling unit also includes a shaft end oil circuit, and both ends of the shaft end oil circuit are respectively connected to the end cover oil circuit and the center oil circuit.

[0015] As a preferred technical solution, the first radial oil circuit includes a first bearing cooling oil circuit and a second bearing cooling oil circuit, and the first bearing cooling oil circuit and the second bearing cooling oil circuit are evenly arranged along the circumference of the main shaft; A second preset angle is set between the first bearing cooling oil circuit and the central oil circuit, and a third preset angle is set between the second bearing cooling oil circuit and the central oil circuit.

[0016] As a preferred technical solution, the second radial oil circuit is evenly arranged along the circumference of the main shaft, and the second radial oil circuit includes a first winding inner surface cooling oil circuit and a second winding inner surface cooling oil circuit located at both ends of the main shaft. The first winding inner surface cooling oil circuit and the second winding inner surface cooling oil circuit are respectively arranged at the positions corresponding to the two ends of the stator winding.

[0017] As a preferred technical solution, the oil cooling unit also includes a plurality of rotor core cooling oil circuits, which are arranged along the circumference of the rotor core, and the rotor core cooling oil circuits are connected to the third radial oil circuit one by one. The rotor core cooling oil circuits are used to spray the cooling medium into the rotor core.

[0018] In a second aspect, an embodiment of the present invention provides a permanent magnet synchronous motor, comprising a composite motor cooling system as described in any one of the above items.

[0019] In a third aspect, an embodiment of the present invention provides a vehicle, comprising the permanent magnet synchronous motor as described above.

[0020] One embodiment of the above invention has the following advantages or beneficial effects: The present invention mainly provides a composite motor cooling system, which is suitable for permanent magnet synchronous motors. Compared with the prior art, the present invention integrates a water cooling unit and an oil cooling unit in the motor to form a water-oil dual cooling system, which not only fully utilizes the efficient heat dissipation characteristics of water cooling, but also gives play to the direct cooling effect of oil cooling on various internal structures of the motor. Without increasing the existing axial size of the motor, the overall heat dissipation efficiency of the motor is significantly improved, and at the same time replaces the oil-water heat exchanger, removes the redundant structure of the electric drive system, and has obvious effects on improving the winding current density and power density of the motor.

[0021] Specifically, the present invention adopts a multi-layer nested water and oil circuit structure so that the flow path of the cooling medium covers the surface of the motor housing to the maximum extent, while achieving reasonable distribution of the cooling medium in the radial and axial directions, ensuring uniformity and stability of heat dissipation.

[0022] By setting an angle-adjustable oil groove group on the stator core and combining it with a multi-stage radial oil circuit system in the rotor main shaft, the stator core, stator winding, rotor core and bearings can be cooled at the same time, effectively solving the problem of local overheating inside the motor. While ensuring the cooling effect, it saves installation space to the greatest extent and improves the system integration. It has a significant effect on improving the overload capacity, miniaturization and lightweight of the motor, and is especially suitable for application scenarios such as new energy vehicles that have strict requirements on space and heat dissipation performance.

[0023] In addition, the composite motor cooling system of the present invention has good reliability and maintainability. The cooling units are relatively independent and cooperate with each other. Even if a single cooling circuit fails, the basic cooling function can still be maintained, thereby improving the overall fault tolerance and safety of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments, which constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions explain the present invention and do not constitute improper limitations on the present invention. In the drawings: Figure 1 It is a structural schematic diagram of a composite motor cooling system disclosed in a preferred embodiment of the present invention; Figure 2 It is a schematic diagram of the structure of a motor housing disclosed in a preferred embodiment of the present invention; Figure 3 A cross-sectional view of a motor housing disclosed in a preferred embodiment of the present invention; Figure 4 A schematic structural diagram of a water cooling unit disclosed in a preferred embodiment of the present invention; Figure 5It is a structural schematic diagram of a heat exchange oil circuit disclosed in a preferred embodiment of the present invention; Figure 6 A cross-sectional view of a composite motor cooling system disclosed in a preferred embodiment of the present invention; Figure 7 A cross-sectional view from another angle of a composite motor cooling system disclosed in a preferred embodiment of the present invention; Figure 8 It is a schematic structural diagram of a right end cover disclosed in a preferred embodiment of the present invention; Fig. 9 It is a schematic structural diagram of a stator core disclosed in a preferred embodiment of the present invention; Fig.10 A partial enlarged view of a stator core disclosed in a preferred embodiment of the present invention; Fig.11 A schematic diagram of the structure of a main shaft disclosed in a preferred embodiment of the present invention; Fig.12 A cross-sectional view of a main shaft disclosed in a preferred embodiment of the present invention; Fig.13 A cross-sectional view of a main shaft disclosed in a preferred embodiment of the present invention; Fig.14 It is a schematic structural diagram of a rotor core disclosed in a preferred embodiment of the present invention.

[0025] Description of reference numerals: Motor housing 100, water inlet 110, water outlet 120, outer water channel 130, inner water channel 140, oil inlet 150, oil outlet 160, heat exchange oil channel 170, first housing oil channel cavity 171, second housing oil channel cavity 172, oil cavity 180, left end cover 200, right end cover 300, end cover oil channel 310, stator core 400, first oil groove 410, first group of sub-oil grooves 420, second group of sub-oil grooves 430, main shaft 500, shaft end oil channel 510, center oil channel 520, first bearing cooling oil channel 530, second bearing cooling oil channel 540, first winding inner surface cooling oil channel 550, second winding inner surface cooling oil channel 560, third radial oil channel 570, rotor core 600, rotor core cooling oil channel 610, permanent magnet 700. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. In the description of the present invention, it should be noted that the term "or" is usually used in the sense of including "and / or", unless the content clearly indicates otherwise.

[0027] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or a magnetic connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be internal communication between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. In addition, in the description of this application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0028] Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] With the development of new energy vehicle technology, the power density of automotive permanent magnet synchronous motors continues to increase. When the motor runs at high speed, uneven heat dissipation is prone to occur in local areas such as the stator winding ends, permanent magnets, and rotor cores. Although the existing oil cooling solution can achieve local cooling inside the motor, the overall heat dissipation efficiency is low, which may cause the axial size of the motor to increase and the weight of the motor to increase, seriously restricting the improvement of motor performance.

[0030] refer to Figure 1 , Figure 6 , Figure 7 In a preferred embodiment, the permanent magnet synchronous motor includes a motor housing 100, the ends of which are provided with a left end cover 200 and a right end cover 300, and a stator and a rotor are provided inside, wherein the stator includes a stator core 400 and a stator winding provided on the stator core 400, and the stator winding has an end extending out of the stator core 400, which is defined as a winding end in this embodiment; the rotor includes a main shaft 500, a rotor core 600 and a permanent magnet 700 provided in the rotor core 600, and the main shaft 500 cooperates with the bearing so that the rotor can rotate relative to the stator. During the operation of the motor, the stator winding is energized to generate a rotating magnetic field, which drives the rotor provided with the permanent magnet 700 to rotate, thereby realizing the conversion of electrical energy into mechanical energy.

[0031] During high-speed operation of the motor, components such as the stator winding, permanent magnet 700 and rotor core 600 will generate a large amount of heat. If the heat cannot be dissipated in time, the temperature of the motor components will rise rapidly, affecting the operating efficiency and service life of the motor. To solve this problem, in a preferred embodiment of the present invention, a composite motor cooling system suitable for a permanent magnet synchronous motor is provided. The system can perform oil spray cooling on the winding ends of the stator and water cooling on the motor housing 100 without increasing the axial size of the motor. At the same time, heat exchange is performed during the oil-water circulation cooling process, thereby improving the heat exchange efficiency and cooling effect of the motor, thereby improving the stator winding current density and the motor power density.

[0032] like Figure 1 In a preferred embodiment, the composite motor cooling system includes a motor housing 100, a stator, a rotor, a water cooling unit and an oil cooling unit. The motor housing 100 is provided with a left end cover 200 and a right end cover 300 at both ends. The stator and the rotor are encapsulated in the motor housing 100. The water cooling unit is arranged on the motor housing 100, and the oil cooling unit is arranged in the motor housing 100, the stator and the rotor. It should be noted that the composite motor cooling system in this embodiment is closely integrated with the basic structure of the permanent magnet synchronous motor, wherein the motor housing 100 is not only the basic support structure of the permanent magnet synchronous motor, but also an important part of the cooling system, which is used to arrange the flow channels of the water cooling unit and the oil cooling unit; the right end cover 300 not only supports the bearing, but also includes part of the channel of the oil cooling unit; the stator and the rotor are respectively provided with specific structures for the oil cooling unit, and these structures are combined with the motor body to form a highly integrated cooling system, which can ensure the cooling effect while avoiding the space waste caused by the external cooling device.

[0033] refer to Figure 1 — Figure 4 In a preferred embodiment, the water cooling unit includes an outer water channel 130 and an inner water channel 140 arranged along the circumference of the motor housing 100, both of which are arranged in a U shape and are connected to each other. This U-shaped structure allows the cooling water to flow back and forth along the axial direction of the motor housing 100, thereby extending the contact time between the cooling water and the motor housing 100. The motor housing 100 is provided with a water inlet 110 and a water outlet 120, both of which are connected to the outer water channel 130 and the inner water channel 140. The cooling water introduced by the water inlet 110 first enters the outer water channel 130, passes through the U-shaped channel, enters the inner water channel 140, and finally flows out from the water outlet 120, forming a complete water circulation system.

[0034] Preferably, in order to increase the heat exchange area of ​​water cooling, multiple groups of outer water channels 130 and inner water channels 140 are arranged along the circumference of the motor housing 100, and two adjacent groups of water channels are connected by connecting sections to ensure uniform heat dissipation of the motor housing 100 by water cooling and avoid the generation of local hot spots.

[0035] like Figure 5 — Figure 7 Preferably, the oil cooling unit includes a heat exchange oil circuit 170 arranged on the motor housing 100, and the heat exchange oil circuit 170 is arranged between the outer water circuit 130 and the inner water circuit 140. The heat exchange oil circuit 170 is also arranged in a U shape. This sandwich layout enables the heat exchange oil circuit 170 to fully exchange heat with the water circuit, thereby improving the cooling effect of the oil cooling medium.

[0036] Preferably, the motor housing 100 is provided with an oil inlet 150 and an oil outlet 160, and the oil inlet 150 is connected to the heat exchange oil circuit 170. The cooling oil introduced by the oil inlet 150 is first pre-cooled through the heat exchange oil circuit 170, and then enters the subsequent oil circuit of the oil cooling unit after the temperature is reduced; preferably, the oil cooling unit also includes an oil chamber 180 arranged inside the outer housing, and the oil chamber 180 is connected to the oil outlet 160, and is used to collect the cooling oil flowing out from various parts of the stator and the rotor, and guide it out. The oil chamber 180 is preferably arranged at the bottom of the motor housing 100, and the cooling oil is naturally collected by gravity to improve the oil return efficiency.

[0037] like Figure 3 Preferably, each group of outer water channels 130 corresponds to each group of inner water channels 140 in the radial direction, and multiple groups of heat exchange oil channels 170 are also provided along the circumference of the motor housing 100, and each group of heat exchange oil channels 170 is correspondingly provided between a group of outer water channels 130 and a group of inner water channels 140 to ensure that the heat exchange oil channels 170 are closely fitted with the water channels, thereby improving the heat exchange efficiency, and making the structure of the entire cooling system more compact and symmetrical, which is beneficial to the assembly and maintenance of the system. Through the synergistic effect of the inner water channels 140, the outer water channels 130 and the heat exchange oil channels 170, efficient heat dissipation of the motor housing 100 is achieved.

[0038] In a preferred embodiment, each group of outer water channels 130, inner water channels 140 and heat exchange oil channels 170 has certain dimensions in the axial and circumferential directions; optionally, in the axial direction, the length of the outer water channels 130, inner water channels 140 and heat exchange oil channels 170 basically covers the effective length of the motor housing 100 to ensure sufficient cooling of the motor body; in the circumferential direction, the width of each group of inner water channels 140, outer water channels 130 and heat exchange oil channels 170 is about 1 / 6, 1 / 8 or other proportions of the circumferential dimension of the motor housing 100, so that the outer water channels of the inner water channels 140 and heat exchange oil channels 170 of the array can be evenly arranged in the circumferential direction of the motor housing 100. By reasonably setting the dimensions of the water channels and heat exchange oil channels 170 in the axial and circumferential directions, sufficient heat exchange area is guaranteed, and sufficient heat exchange between the cooling medium and the motor housing 100 is achieved, thereby improving the heat exchange efficiency of the entire cooling system.

[0039] It should be noted that those skilled in the art can adaptively adjust parameters such as the type of pipeline material, the dimensions of the inner water channel 140, the outer water channel 130 and the heat exchange oil channel 170 according to actual application scenarios, such as the specific model of the motor, power level, heat dissipation requirements, installation space and other factors. As long as the heat dissipation requirements of the motor can be met, no specific limitations are made in this embodiment.

[0040] like Figure 5 , Figure 7 , Figure 8 In a preferred embodiment, the cooling oil after pre-cooling in the heat exchange oil circuit 170 enters the structure of the oil cooling unit arranged in the stator and the rotor respectively through two different connecting passages, wherein the heat exchange oil circuit 170 is connected with the first shell oil circuit cavity 171 arranged on the inner wall of the motor housing 100 through the first connecting passage, and the first shell oil circuit cavity 171 is connected with the stator for cooling the stator part; the heat exchange oil circuit 170 is connected with the second shell oil circuit cavity 172 arranged on the inner wall of the motor housing 100 through the second connecting passage, and the second shell oil circuit cavity 172 extends axially to the right end cover 300, and is connected with the end cover oil circuit 310 arranged on the right end cover 300, and finally the cooling oil is transported to the rotor part through the end cover oil circuit 310.

[0041] like Figure 6 , Figure 7 , Fig. 9 , Fig.10In a preferred embodiment, the oil cooling unit is provided with a first oil groove 410 and a second oil groove in the stator. The first oil groove 410 is circumferentially arranged along the outer diameter of the stator core 400, preferably arranged at the middle position of the outer diameter of the stator core 400. The first oil groove 410 is connected to the first shell oil path cavity 171. A plurality of second oil grooves are arranged at the axial end of the first oil groove 410 and arranged along the circumferential direction. The two are interconnected and used to transport cooling oil to the second oil groove. The second oil groove includes a first group of sub-oil grooves 420 and a second group of sub-oil grooves 430, both of which are evenly arranged along the circumference of the stator core 400. The first group of sub-oil grooves 420 extend in the axial direction, and the second group of sub-oil grooves 430 extend obliquely, and a first preset angle α1 is set between the first group of sub-oil grooves 420, and the second group of sub-oil grooves 430 pass through the stator core 400, and are used to spray cooling oil to the outer surface of the winding end in a large area.

[0042] Preferably, the first preset angle α1 is matched with the height of the winding end and / or the pressure of the cooling medium, so as to enable the cooling medium to be sprayed onto the outer surface of the end of the stator winding along a predetermined trajectory.

[0043] Specifically, when the height of the winding end is relatively large, the value of the first preset angle α1 can be increased accordingly so that the cooling oil can cover the surface of the winding end at a higher position; when the height of the winding end is relatively small, the first preset angle α1 can be reduced accordingly to prevent the cooling oil from being sprayed beyond the target area.

[0044] Alternatively, when the cooling oil pressure is high, a smaller first preset angle α1 can be selected. At this time, the higher pressure can ensure that the cooling oil reaches the expected height. When the pressure is low, the first preset angle α1 needs to be increased to compensate for the range impact caused by insufficient pressure.

[0045] In practical applications, a correspondence between the first preset angle α1 and the winding end height and the cooling medium pressure can be established according to the specific parameters of different types of motors to adapt the optimal tilt angle for motors of different specifications. In this embodiment, the first preset angle α1 is configured to be 45°.

[0046] It should also be noted that the specific dimensions of the first oil tank 410 and the second oil tank need to be designed according to the actual situation of the motor. As the main oil passage, the cross-sectional area of ​​the first oil tank 410 needs to meet the overall flow requirements; the dimensions of the second oil tank, especially the second group of sub-oil tanks 430, need to ensure a suitable injection speed and injection volume, and these dimensions can be adjusted according to the specific parameters of the motor such as power level, cooling requirements, and heat dissipation requirements.

[0047] In a preferred embodiment, the depth and width of the first oil groove 410 can be determined according to the size of the stator core 400 and the total flow rate of the cooling oil to ensure that there is enough cross-sectional area for the cooling oil to flow; the size of the first group of sub-oil grooves 420 and the second group of sub-oil grooves 430 can be set according to the required injection pressure and flow rate, so as to ensure sufficient cooling effect and avoid excessive pressure loss. Those skilled in the art can determine the optimal combination of oil groove sizes through corresponding calculations to achieve compact structure and material saving while ensuring cooling effect, and the specific size is not limited in this embodiment.

[0048] like Fig.11 — Fig.13 In a preferred embodiment, the oil cooling unit is configured with a central oil circuit 520, a shaft end oil circuit 510 and several radial oil circuits in the rotor, and an end cover oil circuit 310 is configured in the right end cover 300. The central oil circuit 520 and the shaft end oil circuit 510 are both configured in the main shaft 500 of the rotor, and the two are axially connected. The other end of the shaft end oil circuit 510 is connected to the end cover oil circuit 310; the radial oil circuit is circumferentially arranged on the main shaft 500, and the central oil circuit 520 is connected with several radial oil circuits. The cooling oil entering the central oil circuit 520 can enter the radial oil circuit through the rotation of the main shaft 500. The radial oil circuit includes a first radial oil circuit, a second radial oil circuit and a third radial oil circuit 570, wherein the first radial oil circuit is used to cool the bearing to reduce the operating temperature of the bearing and extend the service life of the bearing, the second radial oil circuit is used to cool the inner surface of the winding and improve the heat dissipation efficiency of the winding, and the third radial oil circuit 570 is used to cool the rotor core 600. By setting up multi-branch radial oil circuits, precise cooling of key motor components in different regions can be achieved, avoiding the situation where some areas are overcooled and other areas are undercooled. At the same time, each radial oil circuit is supplied with oil through a unified central oil circuit 520, which simplifies the overall oil circuit structure and improves the reliability of the system.

[0049] Preferably, the number of the first radial oil circuit, the second radial oil circuit, and the third radial oil circuit 570 can be the same or different. The number of each radial oil circuit can be adaptively adjusted according to the heating characteristics and cooling requirements of different components to achieve a targeted cooling effect. The specific number is not limited here.

[0050] In a preferred embodiment, the first radial oil circuit includes two groups of bearing cooling oil circuits, namely a first bearing cooling oil circuit 530 and a second bearing cooling oil circuit 540 arranged at the left and right ends of the main shaft 500. Both are evenly arranged along the circumference of the main shaft 500 and are used to cool the bearings at both ends of the main shaft 500.

[0051] like Fig.12 , Fig.13Preferably, in order to enable the cooling oil to be accurately sprayed to the target position of the bearing, a second preset angle α2 is provided between the first bearing cooling oil circuit 530 and the central oil circuit 520, and a third preset angle α3 is provided between the second bearing cooling oil circuit 540 and the central oil circuit 520. The second preset angle α2 and the third preset angle α3 are both adapted to the specific installation position and cooling requirements of the bearing, so as to ensure that the bearings at both ends of the main shaft 500 can be evenly and fully cooled. By precisely controlling the preset angles, the cooling oil can be directly sprayed to the key parts of the bearing with an optimal trajectory, thereby improving the cooling efficiency.

[0052] Preferably, the second preset angle α2 and the third preset angle α3 can be independently adjusted according to actual working conditions. In the present embodiment, the second preset angle α2 is configured to be 40°, and the third preset angle α3 is configured to be 60°.

[0053] In a preferred embodiment, the second radial oil circuit includes a first winding inner surface cooling oil circuit 550 and a second winding inner surface cooling oil circuit 560 located at both ends of the main shaft 500, both of which are evenly arranged along the circumference of the main shaft 500, and are respectively arranged at positions corresponding to both ends of the stator winding. By arranging cooling oil circuits at both ends of the main shaft 500, the cooling oil can spray and cool the inner surface of the stator winding from two directions at the same time, and can evenly cover the inner surface of the entire stator winding to avoid the occurrence of local overheating, and achieve a more uniform and comprehensive cooling effect.

[0054] like Fig.14 In a preferred embodiment, the rotor core 600 is provided with a plurality of rotor core cooling oil circuits 610, each of which extends radially along the rotor core 600, and each of which corresponds one-to-one to the third radial oil circuit 570 on the main shaft 500, ensuring that the cooling oil can be directly injected into the interior of the rotor core 600 and realizing the cooling of the rotor core 600 layer by layer from the inside to the outside. Preferably, the rotor core cooling oil circuits 610 are evenly distributed along the circumference of the rotor core 600 to realize the overall uniform cooling of the rotor core 600.

[0055] In this embodiment, the composite motor cooling system is configured as a dual cooling system combining water cooling and oil cooling, and its working process is as follows: During the water cooling process of the water cooling unit, cooling water first flows in from the water inlet 110 , circulates along the motor housing 100 through the outer water channel 130 and the inner water channel 140 , and then flows out through the water outlet 120 after one cycle to achieve comprehensive cooling of the motor housing 100 .

[0056] During the oil circuit of the oil cooling unit, the cooling oil flows into the heat exchange oil circuit 170 through the oil inlet 150, and then is divided into two branches. The cooling oil in one branch passes through the first connecting passage and the first shell oil circuit cavity 171 and enters the stator, and the cooling oil in the other branch passes through the second connecting passage, the second shell oil circuit cavity 172 and the end cover oil circuit 310 and enters the rotor.

[0057] After entering the stator, the cooling oil passes through the first oil groove 410 into the second oil groove, and then is evenly sprayed along the second group of sub-oil grooves 430 to the outer surface of the winding end. Finally, the cooling oil passes through the oil cavity 180 and flows out through the oil outlet 160.

[0058] After the cooling oil enters the rotor, it enters the center oil circuit 520 through the shaft end oil circuit 510. The cooling oil in the center oil circuit 520 can enter the various radial oil circuits through the rotation of the main shaft 500. The cooling oil entering the first radial oil circuit can be sprayed onto the bearings, the cooling oil entering the second radial oil circuit can be sprayed onto the inner surface of the winding end, and the cooling oil entering the third radial oil circuit 570 can be sprayed into the rotor core 600 through the rotor core cooling oil circuit 610. The aforementioned cooling oils finally pass through the oil chamber 180 and flow out through the oil outlet 160.

[0059] In one embodiment of the present invention, a permanent magnet synchronous motor is further provided, comprising the composite motor cooling system as described above. Specifically, other structures of the permanent magnet synchronous motor, such as the arrangement of the stator core 400 and the stator winding, the structural design of the rotor core 600, the installation method of the permanent magnet 700, and the type of bearing, etc., can be flexibly adjusted and optimized according to actual application requirements, and the embodiment of the present invention does not specifically limit this.

[0060] By adopting the composite motor cooling system of the present invention, the cooling effect of the permanent magnet synchronous motor can be effectively improved, the operating temperature of the motor can be reduced, and the power density and operating reliability of the motor can be improved.

[0061] An embodiment of the present invention further provides a vehicle, preferably a pure electric new energy vehicle, including the permanent magnet synchronous motor as described above. Other structures of the vehicle, such as the configuration of the power battery system, the design of the vehicle control system, the layout of the transmission system, as well as the body structure, chassis system, etc., can be flexibly adjusted and optimized according to actual application requirements, and the embodiment of the present invention does not make specific limitations on this.

[0062] Preferably, the vehicle can also be a purely electric commercial vehicle. By adopting the permanent magnet synchronous motor of the present invention, the power density and operating reliability of the vehicle drive system can be improved, the performance of the whole vehicle can be effectively improved, and strong support can be provided for the development of new energy vehicles.

[0063] Although example embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above example embodiments are merely exemplary and are not intended to limit the scope of the present application to this. Those of ordinary skill in the art may make various changes and modifications therein without departing from the scope and spirit of the present application. All these changes and modifications are intended to be included within the scope of the present application as required by the appended claims.

[0064] In the description provided herein, a large number of specific details are described. However, it is understood that the embodiments of the present application can be practiced without these specific details. In some instances, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this description.

[0065] Similarly, it should be understood that in order to streamline the present application and help understand one or more of the various inventive aspects, in the description of the exemplary embodiments of the present application, the various features of the present application are sometimes grouped together into a single embodiment, figure, or description thereof. However, the method of the present application should not be interpreted as reflecting the following intention: the claimed application requires more features than the features clearly stated in each claim. More specifically, as reflected in the corresponding claims, the inventive point is that the corresponding technical problem can be solved with features less than all the features of a single disclosed embodiment. Therefore, the claims following the specific embodiment are hereby explicitly incorporated into the specific embodiment, wherein each claim itself serves as a separate embodiment of the present application.

[0066] It will be understood by those skilled in the art that, except for mutually exclusive features, all features disclosed in this specification (including the accompanying claims, abstract and drawings) and all processes or units of any method or device disclosed in this specification may be combined in any combination. Unless otherwise expressly stated, each feature disclosed in this specification (including the accompanying claims, abstract and drawings) may be replaced by an alternative feature that provides the same, equivalent or similar purpose.

Claims

1. A composite motor cooling system, characterized in that: It includes a motor housing, a stator, a rotor, a water cooling unit and an oil cooling unit. End covers are provided at both ends of the motor housing. The stator and the rotor are encapsulated in the motor housing. The water cooling unit is arranged on the motor housing, and comprises an outer water channel and an inner water channel arranged along the circumference of the motor housing; The oil cooling unit is arranged in the motor housing, the stator and the rotor, and includes a heat exchange oil circuit, a first oil tank, a second oil tank, a central oil circuit and a radial oil circuit; The heat exchange oil circuit is arranged between the outer water circuit and the inner water circuit, and the heat exchange oil circuit is respectively connected with the first oil tank and the central oil circuit; The first oil groove is arranged circumferentially along the outer diameter of the stator core of the stator, and a plurality of the second oil grooves are arranged at the axial ends of the first oil groove and arranged circumferentially, and the second oil grooves are connected to the first oil grooves; The central oil circuit is axially arranged in the main shaft of the rotor, and the plurality of radial oil circuits are arranged circumferentially along the main shaft and are connected to the central oil circuit. The radial oil circuits include a first radial oil circuit for cooling the bearing, a second radial oil circuit for cooling the inner surface of the winding, and a third radial oil circuit for cooling the rotor core.

2. The composite motor cooling system according to claim 1, characterized in that: The outer water channel and the inner water channel are both arranged in a U shape and are connected to each other. The motor housing is provided with a water inlet and a water outlet, and the water inlet and the water outlet are both connected to the outer water channel and the inner water channel.

3. The composite motor cooling system according to claim 2, characterized in that: The heat exchange oil circuit is arranged in a U shape, the motor housing is provided with an oil inlet and an oil outlet, and the oil inlet is connected to the heat exchange oil circuit; The oil cooling unit further comprises an end cover oil circuit arranged on the end cover, an oil cavity arranged inside the motor housing, a first housing oil circuit cavity and a second housing oil circuit cavity arranged on the inner wall of the motor housing; The heat exchange oil circuit is connected to the first shell oil circuit cavity through a first connecting passage, the heat exchange oil circuit is connected to the second shell oil circuit cavity through a second connecting passage, and the second shell oil circuit cavity extends axially and is connected to the end cover oil circuit; The oil chamber is communicated with the oil outlet and is used for collecting return oil.

4. The composite motor cooling system according to claim 3, characterized in that: The outer layer water channel and the inner layer water channel are provided with a plurality of groups along the circumference of the motor housing, and two groups of water channels adjacent to each other in the circumferential direction are connected through a connecting section; The heat exchange oil passages are provided in a plurality of groups along the circumferential direction of the motor housing, and each group of the heat exchange oil passages is correspondingly arranged between a group of the outer layer water passages and a group of the inner layer water passages.

5. The composite motor cooling system according to claim 3, characterized in that: The first oil groove is arranged at the middle position of the outer diameter of the stator core, and the first oil groove is communicated with the first housing oil passage cavity.

6. The composite motor cooling system according to claim 5, characterized in that: The second oil grooves include a first group of sub-oil grooves and a second group of sub-oil grooves, both of which are evenly arranged along the circumference of the stator core; The first group of sub-oil grooves extend axially, the second group of sub-oil grooves extend obliquely at a first preset angle, and the second group of sub-oil grooves penetrate the stator core and are used to spray cooling medium onto the outer surface of the end of the stator winding.

7. The composite motor cooling system according to claim 6, characterized in that: The first preset angle is matched with the end height of the stator winding and / or the pressure of the cooling medium, and is used to enable the cooling medium to be sprayed onto the outer surface of the end of the stator winding along a predetermined trajectory.

8. The composite motor cooling system according to claim 3, characterized in that: The oil cooling unit further comprises a shaft end oil circuit, and two ends of the shaft end oil circuit are respectively connected with the end cover oil circuit and the center oil circuit.

9. The composite motor cooling system according to claim 1, characterized in that: The first radial oil circuit includes a first bearing cooling oil circuit and a second bearing cooling oil circuit, and the first bearing cooling oil circuit and the second bearing cooling oil circuit are evenly arranged along the circumference of the main shaft; A second preset angle is set between the first bearing cooling oil passage and the central oil passage, and a third preset angle is set between the second bearing cooling oil passage and the central oil passage.

10. The composite motor cooling system according to claim 9, characterized in that: The second radial oil circuit is evenly arranged along the circumference of the main shaft, and the second radial oil circuit includes a first winding inner surface cooling oil circuit and a second winding inner surface cooling oil circuit located at two ends of the main shaft. The first winding inner surface cooling oil circuit and the second winding inner surface cooling oil circuit are respectively arranged at positions corresponding to two ends of the stator winding.

11. The composite motor cooling system according to claim 9, characterized in that: The oil cooling unit also includes a plurality of rotor core cooling oil circuits, which are arranged circumferentially along the rotor core. The rotor core cooling oil circuits are connected to the third radial oil circuits in a one-to-one correspondence, and the rotor core cooling oil circuits are used to spray cooling medium into the rotor core.

12. A permanent magnet synchronous motor, characterized in that: It comprises a composite motor cooling system as described in any one of claims 1 to 11.

13. A vehicle, characterized in that: Comprising the permanent magnet synchronous motor as claimed in claim 12.

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