A composite motor cooling system, permanent magnet synchronous motor and vehicle

Abstract

The present invention relates to a composite motor cooling system, a permanent magnet synchronous motor and a vehicle, wherein the cooling system comprises a motor housing, a stator, a rotor, a water cooling unit and an oil cooling unit; the water cooling unit is arranged on the motor housing and comprises an outer water channel and an inner water channel arranged circumferentially along the motor housing; the oil cooling unit comprises a heat exchange oil channel, a first oil tank, a second oil tank, a central oil channel and a radial oil channel; the heat exchange oil channel is arranged between the outer water channel and the inner water channel and is respectively connected to the first oil tank and the central oil channel; the first oil tank is arranged circumferentially along the outer diameter of the stator core, and a plurality of second oil tanks are arranged at the axial end of the first oil tank and are connected thereto and are arranged circumferentially; the central oil channel is axially arranged in the main shaft of the rotor, and a plurality of radial oil channels are arranged circumferentially along the main shaft and are connected to the central oil channel, including a first radial oil channel for cooling the bearing, a second radial oil channel for cooling the inner surface of the winding, and a third radial oil channel for cooling the rotor 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 motor operation, the increasing demands for winding current density and overall power density lead to increasingly compact motor structures, resulting in rapidly rising winding and operating temperatures. This temperature increase has numerous negative consequences: Firstly, it gradually increases the resistivity of the stator winding, increasing motor losses; secondly, it can cause the winding insulation to fail, leading to short circuits between wires and the risk of motor breakdown; and finally, if the permanent magnet temperature exceeds the allowable range, demagnetization will occur. Therefore, effectively dissipating heat and cooling the permanent magnet synchronous motor and controlling the temperature of each motor component within a safe range has become a pressing technical issue.

[0003] Currently, the end windings of stator oil-immersed motors are typically cooled by either complete oil immersion or by adding an oil spray ring to the top. However, these cooling methods have significant drawbacks: With complete immersion, the cooling oil flows slowly within the cavity due to the small end space, resulting in poor convective heat transfer at the fluid-solid interface, which effectively prevents the end windings from being fully cooled. With top oil spraying, the cooling medium only contacts the outer surface of the end winding, making it difficult to effectively cool the inner and central windings, where heat dissipation is even worse.

[0004] Some improvement schemes have also appeared in the existing technology, such as the use of a special winding oil injection ring structure, which improves 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, which in turn increases the axial size of the motor and increases the weight of the entire 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 solved urgently in this field. Summary of the Invention

[0006] The present 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:

[0008] On the one hand, an embodiment of the present invention provides a composite motor cooling system, comprising 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;

[0009] The water cooling unit is arranged on the motor housing and includes an outer water channel and an inner water channel arranged along the circumference of the motor housing;

[0010] The oil cooling unit is arranged in the motor housing, stator and 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;

[0011] The heat exchange oil circuit is arranged between the outer water circuit and the inner water circuit, and the heat exchange oil circuit is connected to the first oil tank and the central oil circuit respectively;

[0012] The first oil groove is circumferentially arranged along the outer diameter of the stator core of the stator, and a plurality of second oil grooves are arranged at axial ends of the first oil groove and arranged along the circumferential direction, and the second oil grooves are connected to the first oil grooves;

[0013] The central oil circuit is axially arranged in the main shaft of the rotor, and several 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.

[0014] As an optimal 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.

[0015] 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;

[0016] The oil cooling unit further includes an end cover oil passage provided on the end cover, an oil cavity provided inside the motor housing, a first housing oil passage cavity and a second housing oil passage cavity provided on the inner wall of the motor housing;

[0017] 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;

[0018] The oil chamber is connected to the oil outlet and is used to collect the return oil.

[0019] 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 adjacent groups of water channels in the circumferential direction are connected via a connecting section;

[0020] A plurality of heat exchange oil passages are provided along the circumference of the motor housing, and each group of heat exchange oil passages is correspondingly provided between a group of outer water passages and a group of inner water passages.

[0021] As a preferred technical solution, the first oil groove is arranged in the middle position of the outer diameter of the stator core, and the first oil groove is connected to the oil channel cavity of the first shell.

[0022] 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;

[0023] The first group of sub-oil grooves extends axially, the second group of sub-oil grooves extends obliquely at a first preset angle, and the second group of sub-oil grooves passes through the stator core and is used to spray cooling medium onto the outer surface of the end of the stator winding.

[0024] As a preferred technical solution, the first preset angle is adapted to 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.

[0025] As a preferred technical solution, the oil cooling unit further 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.

[0026] 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 both evenly arranged along the circumference of the main shaft;

[0027] 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.

[0028] As a preferred technical solution, the second radial oil circuit is evenly arranged along the circumference of the main shaft. 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.

[0029] 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. The rotor core cooling oil circuits are connected to the third radial oil circuit one-to-one, and the rotor core cooling oil circuits are used to spray the cooling medium into the rotor core.

[0030] In a second aspect, an embodiment of the present invention provides a permanent magnet synchronous motor, comprising the composite motor cooling system as described in any one of the above items.

[0031] In a third aspect, an embodiment of the present invention provides a vehicle comprising the permanent magnet synchronous motor as described above.

[0032] One embodiment of the above invention has the following advantages or beneficial effects:

[0033] The present invention mainly provides a composite motor cooling system, which is suitable for permanent magnet synchronous motors. Compared with the existing technology, 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 fully utilizes the efficient heat dissipation characteristics of water cooling and 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, eliminating the redundant structure of the electric drive system, which has obvious effects on improving the winding current density and power density of the motor.

[0034] 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 a reasonable distribution of the cooling medium in the radial and axial directions, ensuring uniformity and stability of heat dissipation.

[0035] By setting an angle-adjustable oil tank group in 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.

[0036] 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

[0037] 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 are provided to explain the present invention and do not constitute an undue limitation of the present invention. In the drawings:

[0038] Figure 1 A schematic structural diagram of a composite motor cooling system disclosed in a preferred embodiment of the present invention;

[0039] Figure 2 This is a schematic structural diagram of a motor housing disclosed in a preferred embodiment of the present invention;

[0040] Figure 3 A cross-sectional view of a motor housing disclosed in a preferred embodiment of the present invention;

[0041] Figure 4 This is a schematic structural diagram of a water cooling unit disclosed in a preferred embodiment of the present invention;

[0042] Figure 5 This is a schematic structural diagram of a heat exchange oil circuit disclosed in a preferred embodiment of the present invention;

[0043] Figure 6 A cross-sectional view of a composite motor cooling system disclosed in a preferred embodiment of the present invention;

[0044] Figure 7 A cross-sectional view from another angle of the composite motor cooling system disclosed in a preferred embodiment of the present invention;

[0045] Figure 8 This is a schematic structural diagram of a right end cover disclosed in a preferred embodiment of the present invention;

[0046] Figure 9 Schematic diagram of the structure of a stator core disclosed in a preferred embodiment of the present invention;

[0047] Figure 10 A partial enlarged view of a stator core disclosed in a preferred embodiment of the present invention;

[0048] Figure 11 A schematic structural diagram of a main shaft disclosed in a preferred embodiment of the present invention;

[0049] Figure 12 A cross-sectional view of a main shaft disclosed in a preferred embodiment of the present invention;

[0050] Figure 13 A cross-sectional view of a main shaft disclosed in a preferred embodiment of the present invention;

[0051] Figure 14 This is a schematic structural diagram of a rotor core disclosed in a preferred embodiment of the present invention.

[0052] Description of reference numerals:

[0053] 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

[0054] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention and corresponding drawings. In the description of the present invention, it should be noted that the term "or" is generally used in the sense of including "and / or" unless the content clearly indicates otherwise.

[0055] 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 an indirect connection through an intermediate medium, or it can be a communication between the two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the 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.

[0056] Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0057] 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 core. Although the existing oil cooling solution can achieve local cooling inside the motor, the overall heat dissipation efficiency is relatively low, or it 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.

[0058] refer to Figure 1 、 Figure 6 、 Figure 7 In a preferred embodiment, a permanent magnet synchronous motor includes a motor housing 100, with a left end cap 200 and a right end cap 300 provided at the ends of the motor housing 100. A stator and a rotor are provided within the motor housing 100. The stator includes a stator core 400 and a stator winding disposed on the stator core 400. The stator winding has ends extending from the stator core 400, which are defined as winding ends in this embodiment. The rotor includes a main shaft 500, a rotor core 600, and permanent magnets 700 disposed within the rotor core 600. The main shaft 500 cooperates with bearings to enable the rotor to rotate relative to the stator. During motor operation, the stator winding is energized to generate a rotating magnetic field, which drives the rotor, which is equipped with the permanent magnets 700, to rotate, thereby converting electrical energy into mechanical energy.

[0059] During high-speed operation of the motor, components such as the stator winding, permanent magnets 700 and rotor core 600 will generate a large amount of heat. If this 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 spray oil to cool the winding ends of the stator and water-cool the motor housing 100 without increasing the axial size of the motor. At the same time, heat exchange is carried out 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 power density of the motor.

[0060] 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 cap 200 and a right end cap 300 at both ends. The stator and rotor are encapsulated within the motor housing 100. The water cooling unit is disposed on the motor housing 100, and the oil cooling unit is disposed within 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. The motor housing 100 is both the basic support structure of the permanent magnet synchronous motor and an important component of the cooling system, serving as the flow passages for the water cooling unit and the oil cooling unit. The right end cap 300 not only supports the bearings but also contains some channels for the oil cooling unit. The stator and rotor are each provided with specific structures for the oil cooling unit. These structures, combined with the motor body, form a highly integrated cooling system that ensures cooling efficiency while avoiding the space waste caused by external cooling devices.

[0061] refer to Figure 1 — Figure 4In 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 are arranged in a U-shape and are interconnected. This U-shaped structure allows the cooling water to flow back and forth along the axial direction of the motor housing 100, 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. The water inlet 110 and the water outlet 120 are both 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.

[0062] 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 adjacent groups of water channels are connected by connecting sections to ensure uniform heat dissipation of the motor housing 100 by water cooling, thereby avoiding the generation of local hot spots.

[0063] like Figure 5 — Figure 7 Preferably, the oil cooling unit includes a heat exchange oil circuit 170 arranged on the motor housing 100. The heat exchange oil circuit 170 is arranged between the outer water channel 130 and the inner water channel 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 channel, thereby improving the cooling effect of the oil cooling medium.

[0064] 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, which is used to collect the cooling oil flowing out from various parts of the stator and 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.

[0065] like Figure 3 Preferably, each set of outer water channels 130 corresponds radially to each set of inner water channels 140. Multiple sets of heat exchange oil channels 170 are also provided along the circumference of the motor housing 100, with each set of heat exchange oil channels 170 positioned between a set of outer water channels 130 and a set of inner water channels 140. This ensures a close fit between the heat exchange oil channels 170 and the water channels, improving heat exchange efficiency. This also makes the overall cooling system structure more compact and symmetrical, facilitating system assembly and maintenance. The synergistic effect of the inner water channels 140, outer water channels 130, and heat exchange oil channels 170 achieves efficient heat dissipation within the motor housing 100.

[0066] In a preferred embodiment, each set 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 lengths of the outer water channels 130, inner water channels 140, and heat exchange oil channels 170 substantially cover the effective length of the motor housing 100 to ensure adequate cooling of the motor body. In the circumferential direction, the widths of each set of inner water channels 140, outer water channels 130, and heat exchange oil channels 170 are approximately 1 / 6, 1 / 8, or other proportions of the circumferential dimension of the motor housing 100, so that the outer water channels of each set of inner water channels 140 and heat exchange oil channels 170 can be evenly arranged in the circumference of the motor housing 100. By rationally setting the axial and circumferential dimensions of the water channels and heat exchange oil channels 170, sufficient heat exchange area is ensured, 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.

[0067] 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 limitation is made in this embodiment.

[0068] 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 provided in the stator and the rotor respectively through two different connecting passages, wherein the heat exchange oil circuit 170 is connected to the first housing oil circuit cavity 171 provided on the inner wall of the motor housing 100 through a first connecting passage, and the first housing oil circuit cavity 171 is connected to the stator for cooling the stator part; the heat exchange oil circuit 170 is connected to the second housing oil circuit cavity 172 provided on the inner wall of the motor housing 100 through a second connecting passage, and the second housing oil circuit cavity 172 extends axially to the right end cover 300 and is connected to the end cover oil circuit 310 provided on the right end cover 300, and finally the cooling oil is transported to the rotor part through the end cover oil circuit 310.

[0069] like Figure 6 、 Figure 7 、 Figure 9 、 Figure 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 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 passage cavity 171. A plurality of second oil grooves are provided at the axial end of the first oil groove 410 and are arranged circumferentially. The two are connected to each other for transporting 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 axially, and the second group of sub-oil grooves 430 extend obliquely, with a first preset angle α1 set between them and the first group of sub-oil grooves 420. The second group of sub-oil grooves 430 passes through the stator core 400 and is used to spray cooling oil onto the outer surface of the winding end over a large area.

[0070] Preferably, the first preset angle α1 is adapted to 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.

[0071] Specifically, when the height of the winding end is 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 small, the first preset angle α1 can be reduced accordingly to avoid the cooling oil being sprayed beyond the target area.

[0072] 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.

[0073] 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, so as to adapt the optimal tilt angle for motors of different specifications. In this embodiment, the first preset angle α1 is configured to be 45°.

[0074] It should also be noted that the specific dimensions of the first and second oil tanks 410 and 430 need to be designed based on the actual motor's requirements. As the primary oil passage, the cross-sectional area of ​​the first oil tank 410 must meet overall flow requirements. The second oil tank, particularly the second set of sub-oil tanks 430, must be sized to ensure an appropriate injection velocity and volume. These dimensions can be adjusted based on the motor's specific parameters, including power rating, cooling requirements, and heat dissipation requirements.

[0075] In a preferred embodiment, the depth and width of the first oil groove 410 can be determined based on the size of the stator core 400 and the total flow rate of the cooling oil to ensure sufficient cross-sectional area for the cooling oil to circulate. The dimensions of the first and second sets of sub-oil grooves 420 and 430 can be set based on the required injection pressure and flow rate, ensuring sufficient cooling effect while avoiding excessive pressure loss. Those skilled in the art can determine the optimal combination of oil groove dimensions through appropriate calculations to achieve a compact structure and material savings while ensuring cooling effect. Specific dimensions are not limited in this embodiment.

[0076] like Figure 11 — Figure 13 In a preferred embodiment, the oil cooling unit is configured with a central oil passage 520, a shaft end oil passage 510, and several radial oil passages in the rotor, and an end cover oil passage 310 is configured in the right end cover 300. The central oil passage 520 and the shaft end oil passage 510 are both configured in the main shaft 500 of the rotor and are axially connected to each other. The other end of the shaft end oil passage 510 is connected to the end cover oil passage 310. The radial oil passages are circumferentially arranged on the main shaft 500. The central oil passage 520 is connected to several radial oil passages. The cooling oil entering the central oil passage 520 can enter the radial oil passages through the rotation of the main shaft 500. The radial oil passages include a first radial oil passage, a second radial oil passage, and a third radial oil passage 570. Among them, the first radial oil passage 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 passage is used to cool the inner surface of the winding to improve the heat dissipation efficiency of the winding. The third radial oil passage 570 is used to cool the rotor core 600. By setting up multi-branch radial oil circuits, precise cooling of key motor components can be achieved in different areas, 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.

[0077] 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 targeted cooling effects. The specific number is not limited here.

[0078] In a preferred embodiment, the first radial oil circuit includes two sets 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 respectively.

[0079] like Figure 12 、 Figure 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 the optimal trajectory, thereby improving the cooling efficiency.

[0080] Preferably, the second preset angle α2 and the third preset angle α3 can be independently adjusted according to actual working conditions. In this embodiment, the second preset angle α2 is configured to be 40°, and the third preset angle α3 is configured to be 60°.

[0081] 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 either end of the spindle 500. Both circuits are evenly arranged along the circumference of the spindle 500, corresponding to the ends of the stator windings. By providing cooling oil circuits at both ends of the spindle 500, cooling oil can be sprayed onto the inner surface of the stator windings from two directions simultaneously, evenly covering the entire inner surface of the stator windings, preventing localized overheating and achieving more uniform and comprehensive cooling.

[0082] like Figure 14 In a preferred embodiment, the rotor core 600 is provided with multiple rotor core cooling oil passages 610. Each rotor core cooling oil passage 610 extends radially along the rotor core 600. Each rotor core cooling oil passage 610 corresponds one-to-one with a third radial oil passage 570 on the main shaft 500. This ensures that cooling oil can be directly injected into the interior of the rotor core 600 and achieves layer-by-layer cooling of the rotor core 600 from the inside out. Preferably, the rotor core cooling oil passages 610 are evenly distributed along the circumference of the rotor core 600 to achieve uniform cooling of the entire rotor core 600.

[0083] 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:

[0084] During the water cooling process of the water cooling unit, the 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.

[0085] 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 divides into two branches. The cooling oil of one branch enters the stator after passing through the first connecting passage and the first shell oil circuit cavity 171, and the cooling oil of the other branch enters the rotor after passing through the second connecting passage, the second shell oil circuit cavity 172 and the end cover oil circuit 310.

[0086] 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.

[0087] After the cooling oil enters the rotor, it enters the central oil circuit 520 through the shaft end oil circuit 510. The cooling oil in the central 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.

[0088] In one embodiment of the present invention, a permanent magnet synchronous motor is provided, including the composite motor cooling system described above. Specifically, other structures of the permanent magnet synchronous motor, such as the stator core 400 and the arrangement of the stator windings, the structural design of the rotor core 600, the mounting method of the permanent magnets 700, and the selection of the bearing type, can be flexibly adjusted and optimized based on actual application requirements, and are not specifically limited in this embodiment of the present invention.

[0089] 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.

[0090] 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 specifically limit this.

[0091] 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 operational reliability of the vehicle drive system can be increased, effectively improving the performance of the entire vehicle and providing strong support for the development of new energy vehicles.

[0092] Although example embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above example embodiments are merely illustrative and are not intended to limit the scope of the present application. Various changes and modifications may be made therein by those skilled in the art without departing from the scope and spirit of the present application. All such changes and modifications are intended to be included within the scope of the present application as required by the appended claims.

[0093] 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.

[0094] Similarly, it should be understood that in order to streamline the present application and aid in understanding 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, this approach of the present application should not be interpreted as reflecting the intention that the application claimed for protection requires more features than those explicitly recited in each claim. More precisely, as reflected in the corresponding claims, the inventive point is that the corresponding technical problem can be solved with fewer features than all the features of a single disclosed embodiment. Therefore, the claims following the detailed description are hereby expressly incorporated into the detailed description, with each claim itself serving as a separate embodiment of the present application.

[0095] Those skilled in the art will understand that, except where mutually exclusive, all features disclosed in this specification (including the accompanying claims, abstract, and drawings), as well as all processes or units of any method or apparatus disclosed herein, may be combined in any combination. Unless expressly stated otherwise, 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 includes an outer water channel and an inner water channel arranged along the circumference of the motor housing. The cooling water introduced into the motor housing first enters the outer water channel and then enters the inner water channel, and flows out of the motor housing after a cycle. 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 motor housing is provided with an oil inlet connected to the heat exchange oil circuit, and an oil outlet for conducting cooling oil; the heat exchange oil circuit is provided between the outer water circuit and the inner water circuit, and the cooling oil introduced through the oil inlet is first pre-cooled by the heat exchange oil circuit, and then enters the subsequent oil circuit of the oil cooling unit after the temperature is reduced; the heat exchange oil circuit is respectively connected to the first oil tank and the central oil circuit; The first oil groove is circumferentially arranged along the outer diameter of the stator core of the stator, and a plurality of second oil grooves are provided at axial ends of the first oil groove and arranged along the circumferential direction, and the second oil grooves are connected to the first oil grooves; The second oil groove includes a first group of sub-oil grooves and a second group of sub-oil grooves, the first group of sub-oil grooves extending in the axial direction, the second group of sub-oil grooves extending obliquely at a first preset angle, and the second group of sub-oil grooves passing through the stator core; The first preset angle is positively correlated with the height of the end of the stator winding, and negatively correlated with 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; The central oil circuit is axially arranged in the main shaft of the rotor, and several 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 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.

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 oil cooling unit further includes an end cover oil passage provided on the end cover, an oil cavity provided inside the motor housing, a first housing oil passage cavity and a second housing oil passage cavity provided on the inner wall of the motor housing; The heat exchange oil circuit is connected to the first housing oil circuit cavity through a first connecting passage, and the heat exchange oil circuit is connected to the second housing oil circuit cavity through a second connecting passage, and the second housing 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 in a plurality of groups along the circumference of the motor housing, and two circumferentially adjacent groups of water channels are connected via a connecting section; The heat exchange oil passages are provided in a plurality of groups along the circumference of the motor housing, and each group of the heat exchange oil passages is correspondingly provided 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 a 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 first group of sub-oil grooves and the second group of sub-oil grooves are evenly arranged along the circumference of the stator core.

7. The composite motor cooling system according to claim 6, characterized in that: The first preset angle is adapted to the height of the end 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 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.

9. The composite motor cooling system according to claim 1, characterized in that: The first radial oil passage includes a first bearing cooling oil passage and a second bearing cooling oil passage, and the first bearing cooling oil passage and the second bearing cooling oil passage are both 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. 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 positions corresponding to the 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 along the circumference of the rotor core. The rotor core cooling oil circuits are connected to the third radial oil circuits in a one-to-one correspondence. 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: The invention comprises a composite motor cooling system according to any one of claims 1 to 11.

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

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