Oil-cooled electric motor, power assembly and vehicle

Abstract

Provided in the present application are an oil-cooled electric motor, a power assembly and a vehicle. The oil-cooled electric motor comprises a stator and a rotor; a rotor shaft sequentially passes through a first end plate, a rotor core and a second end plate in the circumferential direction of the oil-cooled electric motor; an oil-cooling circuit of the rotor comprises: an oil intake channel and a plurality of oil output holes, the oil intake channel being distributed inside the rotor shaft, and the plurality of oil output holes comprising a plurality of first oil output holes and a plurality of second oil output holes, wherein the plurality of first oil output holes are distributed spaced apart from each other in the circumferential direction of the oil-cooled electric motor and on the side of the first end plate facing away from the rotor core, the plurality of second oil output holes are distributed spaced apart from each other in the circumferential direction of the oil-cooled electric motor and on the side of the second end plate facing away from the rotor core, and at least one of the following is different: the areas of each first oil output hole and each second oil output hole, and the distance between each first oil output hole and the inner circumferential surface of the stator in the radial direction of the oil-cooled electric motor and the distance between each second oil output hole and the inner circumferential surface of the stator in the radial direction of the oil-cooled electric motor. The two ends of the rotor of the oil-cooled electric motor can spray cooling oil in different states to meet different oil cooling requirements of the two ends of a stator winding.

Description

Oil-cooled motors, powertrains and vehicles

[0001] Cross-reference to related applications

[0002] This application claims priority to Chinese Patent Application No. 202411761684.7, filed on November 30, 2024, entitled "Oil-cooled motor, powertrain and vehicle", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of electric motor technology, and more particularly to an oil-cooled electric motor, powertrain, and vehicle. Background Technology

[0004] With the development of new energy vehicles, the electric motors in the vehicle's powertrain are becoming more high-speed, high-density, and miniaturized.

[0005] Currently, cooling oil can be introduced into the rotor of a motor for oil cooling. Specifically, the cooling oil enters the rotor's internal oil passages and flows to both ends of the rotor as the rotor rotates, where it is sprayed out. The cooling oil sprayed out from both sides of the rotor can provide oil cooling to both ends of the stator windings. The end winding structures of the stator windings at both ends along the motor axis are different, and their cooling requirements also differ. Existing rotor oil spraying methods cannot meet these requirements. Summary of the Invention

[0006] This application provides an oil-cooled motor, powertrain, and vehicle. The rotor of the oil-cooled motor can spray cooling oil in different states at both ends to cool the end windings of the stator, thereby meeting the different oil cooling requirements at both ends of the stator windings.

[0007] In a first aspect, embodiments of this application provide an oil-cooled motor, which includes a stator and a rotor. The central hole of the stator is used to accommodate the rotor. The rotor includes a rotor shaft, a rotor core, a first end plate, and a second end plate. The rotor shaft passes through the first end plate, the rotor core, and the second end plate sequentially along the circumference of the oil-cooled motor. The oil cooling circuit of the rotor includes an oil inlet channel and a plurality of oil outlet holes. The oil inlet channel is distributed inside the rotor shaft and is used to deliver cooling oil into the rotor core. The plurality of oil outlet holes are used to discharge the cooling oil inside the rotor. The plurality of oil outlet holes include a plurality of first oil outlet holes and a plurality of second oil outlet holes. The plurality of first oil outlet holes are spaced apart along the circumference of the oil-cooled motor on the side of the first end plate away from the rotor core, and the plurality of second oil outlet holes are spaced apart along the circumference of the oil-cooled motor on the side of the second end plate away from the rotor core. At least one of the areas of each first oil outlet hole and each second oil outlet hole or the distance between each first oil outlet hole and each second oil outlet hole and the inner circumferential surface of the stator along the radial direction of the oil-cooled motor is different.

[0008] In the aforementioned oil-cooled motor, the structures of the oil outlet holes at both ends of the rotor are different, resulting in different spray patterns of the cooling oil at the two ends. This allows the different heat dissipation requirements at both ends of the stator winding to be met, thereby improving the heat dissipation efficiency of the oil-cooled motor. The different oil outlet patterns at both ends of the rotor include at least one of the following: oil quantity, direction, distance, and angle.

[0009] In one embodiment, along the radial direction of the oil-cooled motor, the distance between each first oil outlet and the outer peripheral surface of the rotor is smaller than the distance between each second oil outlet and the outer peripheral surface of the rotor. During high-speed rotation of the rotor, the cooling oil inside the rotor is concentrated towards the outer periphery of the rotor due to centripetal force during its flow. The different radial distances between the oil outlets and the outer peripheral surfaces of the stator can affect the order in which the cooling oil enters the oil outlets and the amount of oil, thereby changing the oil injection state at both ends of the rotor.

[0010] In one embodiment, the area of ​​each first oil outlet hole is larger than the area of ​​each second oil outlet hole. The different areas of the oil outlet holes affect the amount and flow rate of cooling oil, thereby changing the oil injection state at both ends of the rotor.

[0011] In one embodiment, the rotor's oil cooling circuit further includes multiple radial flow channels and multiple axial flow channels. Each radial flow channel connects an oil inlet channel and an axial flow channel. Along the axial direction of the oil-cooled motor, the distance between each radial flow channel and a first oil outlet is greater than the distance between each radial flow channel and a second oil outlet. The different durations of cooling oil supply to both ends of the rotor via the radial flow channels can change the amount of oil flowing to both ends of the rotor, thereby altering the oil injection state at both ends of the rotor.

[0012] In one embodiment, the rotor core includes a first core end face and a second core end face opposite to each other along the axial direction of the oil-cooled motor. Each axial flow channel includes a first opening and a second opening opposite to each other along the axial direction of the oil-cooled motor. The first opening of each axial flow channel is distributed on the first core end face, and the second opening of each axial flow channel is distributed on the second core end face. Each first opening is used to discharge cooling oil through a first oil outlet hole. The distance between each first opening and the outer peripheral surface of the rotor is greater than the distance between each first oil outlet hole and the outer peripheral surface of the rotor. There is a height difference between the first opening and the first oil outlet hole along the radial direction of the oil-cooled motor, facilitating the flow of cooling oil inside the rotor to the first oil outlet hole.

[0013] In one embodiment, each radial flow channel is used to deliver cooling oil to a second opening and a second oil outlet. The distance between each second opening and the outer circumferential surface of the rotor is less than or equal to the distance between the axis of each second oil outlet and the outer circumferential surface of the rotor, allowing the cooling oil inside the rotor to flow more easily to the first oil outlet, thereby regulating the oil spraying state at both ends of the rotor.

[0014] In one embodiment, the area of ​​each first oil outlet hole is greater than or equal to the area of ​​each first opening, and the area of ​​each second oil outlet hole is less than the area of ​​each second opening. The difference in the areas of the first and second oil outlet holes will affect the difference in the amount of oil injected at both ends of the rotor.

[0015] In one embodiment, the rotor core further includes multiple auxiliary flow channels, each including an inlet and an outlet. The inlets of the multiple auxiliary flow channels are spaced circumferentially along the end face of the second core. The inlet of each auxiliary flow channel and the second opening of an axial flow channel are arranged radially along the same side of the oil-cooled motor and connect to the same radial flow channel. The area of ​​the inlet of each auxiliary flow channel is smaller than the area of ​​the second opening of each axial flow channel. The outlets of the multiple auxiliary flow channels are spaced circumferentially along the end face of the first core. The outlet of each auxiliary flow channel and the first opening of an axial flow channel are arranged radially along the same side of the oil-cooled motor and connect to the same first oil outlet. The area of ​​the outlet of each auxiliary flow channel is smaller than the area of ​​the first opening of each axial flow channel. The multiple auxiliary flow channels and the multiple axial flow channels are connected in parallel as part of the rotor's oil cooling circuit, which can improve the rotor's oil cooling effect.

[0016] In one embodiment, the second end plate includes a plurality of radial grooves on the side facing the rotor core. Each radial groove serves as a radial flow channel, and the plurality of radial grooves are arranged at intervals along the circumference of the oil-cooled motor. Each radial groove connects an axial flow channel and a second oil outlet. Along the radial direction of the oil-cooled motor, the distance between each radial groove and the outer circumferential surface of the rotor is smaller than the distance between the second oil outlet and the outer circumferential surface of the rotor, and the distance between the axial flow channel and the outer circumferential surface of the rotor. The cooling oil in the radial flow channel can be partially stored in the radial grooves due to the centripetal force, changing the oil quantity distribution to the second oil outlet and the axial flow channel, thereby changing the oil spray state at both ends of the rotor.

[0017] In one embodiment, along the circumference of the oil-cooled motor, the circumferential width of each radial groove is greater than the circumferential width of the connected second oil outlet and less than the circumferential width of the second opening of the axial flow channel. The amount of cooling oil in the radial grooves is sufficient to supply the axial flow channel and the second oil outlet.

[0018] In one embodiment, the side of the second end plate facing the rotor core further includes an annular groove, which surrounds and connects multiple radial grooves. The annular groove receives cooling oil from the radial flow channels and allows the cooling oil to circumferentially circumferentially circumferentially cool the motor, preventing localized hot spots on the rotor, thus improving rotor stability and optimizing the performance of the oil-cooled motor. Specifically, along the radial direction of the oil-cooled motor, the distance between the annular groove and the outer circumferential surface of the rotor is less than or equal to the distance between each second oil outlet hole and the outer circumferential surface of the rotor, and less than the distance between the second opening of the axial flow channel and the outer circumferential surface of the rotor. This allows the annular groove to function as a storage area for cooling oil, ensuring the supply of cooling oil to the axial flow channels and the second cooling holes.

[0019] In one embodiment, the side of the first end plate facing the rotor core includes a plurality of first oil inlets, and the side of the second end plate facing the rotor core includes a plurality of second oil inlets. Each first oil inlet is used to connect to a first oil outlet, and each second oil inlet is used to connect to a second oil outlet. The area of ​​each first oil inlet is larger than the area of ​​each second oil inlet, so that the amount of cooling oil reaching the first oil outlet and the second oil outlet is different.

[0020] In one embodiment, the distance between each first oil inlet and the outer peripheral surface of the rotor is greater than or equal to the distance between each first oil outlet and the outer peripheral surface of the rotor. By adjusting the structure of the connected first oil inlets and first oil outlets, the angle and direction of the cooling oil ejected from the first oil outlets can be changed. Similarly, the distance between each second oil inlet and the outer peripheral surface of the rotor is greater than or equal to the distance between each second oil outlet and the outer peripheral surface of the rotor. By adjusting the structure of the second oil outlets and second oil inlets, the angle and direction of the cooling oil ejected from the first oil outlets can be changed.

[0021] Secondly, embodiments of this application also provide a powertrain, which includes a reducer and an oil-cooled motor as provided in the first aspect above, wherein the rotor shaft of the oil-cooled motor is connected to the input shaft of the reducer, and the reducer can be replaced by a transmission.

[0022] Thirdly, embodiments of this application also provide an electric vehicle, which includes wheels and the powertrain provided in the second aspect above. The oil-cooled motor is connected to the wheels via a transmission mechanism, thereby further transmitting driving force to the wheels to drive the electric vehicle.

[0023] For the technical effects that can be achieved in the second and third aspects mentioned above, please refer to the description of the technical effects that can be achieved by the corresponding design scheme in the first aspect mentioned above. This application will not repeat them here. Attached Figure Description

[0024] Figure 1 is a structural schematic diagram of a vehicle provided in an embodiment of this application;

[0025] Figure 2 is a structural schematic diagram of a powertrain provided in an embodiment of this application;

[0026] Figure 3 is a cross-sectional structural diagram of an oil-cooled motor provided in an embodiment of this application;

[0027] Figure 4a is a schematic diagram of the rotor structure of an oil-cooled motor provided in an embodiment of this application;

[0028] Figure 4b is an exploded view of the rotor of an oil-cooled motor provided in an embodiment of this application;

[0029] Figure 4c is an exploded view of the rotor of an oil-cooled motor provided in an embodiment of this application;

[0030] Figure 5a is a schematic diagram of the rotor structure of an oil-cooled motor provided in an embodiment of this application;

[0031] Figure 5b is an exploded view of the rotor of an oil-cooled motor provided in an embodiment of this application;

[0032] Figure 6a is a partial cross-sectional view of the rotor of an oil-cooled motor provided in an embodiment of this application;

[0033] Figure 6b is a partial cross-sectional view of the rotor of an oil-cooled motor provided in an embodiment of this application;

[0034] Figure 7 is a partial cross-sectional view of the rotor of an oil-cooled motor provided in an embodiment of this application;

[0035] Figure 8 is a partial cross-sectional schematic diagram of the rotor structure of an oil-cooled motor provided in an embodiment of this application;

[0036] Figure 9 is a partial cross-sectional schematic diagram of an oil-cooled motor provided in an embodiment of this application;

[0037] Figure 10a is a schematic diagram of the structure of the second end plate of an oil-cooled motor provided in an embodiment of this application;

[0038] Figure 10b is a cross-sectional view of the second end plate of an oil-cooled motor provided in an embodiment of this application;

[0039] Figure 11a is a schematic cross-sectional view of the rotor of an oil-cooled motor provided in an embodiment of this application;

[0040] Figure 11b is a cross-sectional schematic diagram of a partial structure of an oil-cooled motor provided in an embodiment of this application;

[0041] Figure 12 is a schematic diagram of the structure of the second end plate of an oil-cooled motor provided in an embodiment of this application;

[0042] Figure 13 is a partial cross-sectional schematic diagram of the rotor structure of an oil-cooled motor provided in an embodiment of this application;

[0043] Figure 14a is a schematic diagram of the rotor laminations and magnets of an oil-cooled motor provided in an embodiment of this application;

[0044] Figure 14b is a schematic diagram of the rotor laminations and magnets of an oil-cooled motor provided in an embodiment of this application.

[0045] Reference numerals: 1000, Powertrain; 2000, Transmission Mechanism; 3000, Wheel; 100, Oil-cooled Motor; 200, Motor Controller; 300, Reducer; 10, Rotor; 20, Stator; 201, Stator Core; 202, Stator Winding; 30, Housing; 1, Rotor Shaft; 11, Oil Inlet Channel; 12, Annular Shoulder; 2, Rotor Core; 21, Rotor Laminations; 211, Cooling Hole; 212, Mounting Hole; 213, Auxiliary Cooling Hole; 22, Magnet; 3, End Plate; 3a, First End Plate; 3b, Second End Plate; 31, Oil Outlet Hole; 31a, First Oil Outlet Hole; 31b, Second Oil Outlet Hole; 32a, First Oil Inlet; 32b, Second Oil Inlet; 4, Fixing Component; 4a, First Fixing Component; 4b, Second Fixing Component; 5, Rotor Sleeve; a1, First core end face; a2, Second core end face; d11, Axial channel; d12, Radial channel; d21, Axial flow channel; d211, First opening; d212, Second opening; d22, Radial flow channel; d23, Auxiliary flow channel; d31, First oil outlet channel; d32, Second oil outlet channel; d33, Radial groove; d34, Annular groove; k1, First central hole; k2, Second central hole; k3, Third central hole; t1, Axial groove; t2, Axial protrusion. Detailed Implementation

[0046] In oil-cooled motors, the cooling oil supplied to the rotor can be sprayed out from both axial ends of the rotor to provide oil cooling for the stator windings. The two ends of the stator windings have different requirements for cooling oil.

[0047] Based on this, embodiments of this application provide an oil-cooled motor, a powertrain, and a vehicle. The rotor of the oil-cooled motor can adjust the oil output on both sides of the axial direction to meet the cooling requirements of the oil-cooled motor and improve its efficiency.

[0048] To make the objectives, technical solutions, and advantages of this application clearer, the application will now be described in further detail with reference to the accompanying drawings.

[0049] Figure 1 is a structural schematic diagram of an electric vehicle provided in an embodiment of this application. As shown in Figure 1, the electric vehicle is a wheeled device driven or towed by a power unit, specifically it can be a pure electric vehicle (pure EV / battery EV), a hybrid electric vehicle (HEV), a range-extended electric vehicle (REEV), or a plug-in hybrid electric vehicle (PHEV), etc. The vehicle includes a powertrain 1000, a transmission mechanism 2000, and wheels 3000. The powertrain 1000 drives the wheels 3000 through the transmission mechanism 2000. The powertrain 1000 is used to convert electrical energy into mechanical energy. The transmission mechanism 2000 is used to connect the powertrain 1000 and the wheels 3000. The vehicle also includes a frame to withstand the loads of the vehicle's internal and external environment, and a battery for supplying power to the powertrain 1000.

[0050] Figure 2 is a schematic diagram of the powertrain 1000 provided in an embodiment of this application. As shown in Figure 2, the powertrain 1000 includes an oil-cooled motor 100 and a motor controller 200. The motor controller 200 is used to convert the DC power supplied by the battery into AC power and deliver the AC power to the oil-cooled motor 100. In one embodiment, the powertrain 1000 also includes a reducer 300, and the power output end of the oil-cooled motor 100 is connected to the vehicle's wheels 3000 through the reducer 300. The reducer 300 can also be referred to as a transmission. The oil-cooled motor 100 of an electric vehicle is typically a permanent magnet synchronous or AC asynchronous motor.

[0051] Figure 3 is a schematic cross-sectional view of an oil-cooled motor 100. As shown in Figure 3, the oil-cooled motor 100 includes a rotor 10, a stator 20, and a housing 30. The stator 20 and a portion of the rotor 10 are housed within the housing 30. The rotor 10 includes a rotor shaft 1 and a rotor core 2. The rotor core 2 is coaxially fixed to the rotor shaft 1. One end of the rotor shaft 1 is rotatably mounted on the housing 30, and the other end extends out of the housing 30 for transmission connection to a reducer 300. The rotor shaft 1 can also be considered as the motor shaft of the oil-cooled motor 100. The stator 20 is sleeved on the rotor core 2. The stator 20 includes a stator core 201 and a stator winding 202 wound around the stator core 201. When energized, a magnetic field is formed in the central hole of the stator core 201, allowing the rotor 10 to rotate around the axis of the rotor shaft 1 in the magnetic field. The stator winding 202 includes an end winding protruding from the axial end face of the stator core 201. Along the axial direction of the oil-cooled motor 100, one end of the stator winding 202 is a cross-line terminal, and the other end is a terminal. The terminal of the stator winding 202 is used to connect three-phase power, and the structure of the terminal differs from that of the cross-line segment.

[0052] The rotor 10 provided in this embodiment includes an internal oil cooling circuit. Cooling oil is introduced into the oil cooling circuit within the rotor 10 to perform liquid cooling heat dissipation on the rotor 10. Finally, the cooling oil can be sprayed out from the two axial ends of the rotor 10. As shown by the dashed arrows in Figure 3, the cooling oil sprayed from both axial ends of the rotor 10 can spray heat dissipation onto the two end windings of the stator winding 202. Considering the different structures of the two end windings of the stator winding 202, the rotor 10 provided in this embodiment features differentiated designs for the oil spray nozzles at both ends to adjust the state of the cooling oil sprayed from both ends of the rotor 10, meeting the different liquid cooling needs of the two end windings, thereby improving the cooling efficiency of the oil-cooled motor 100 and thus improving the performance of the oil-cooled motor 100.

[0053] In this embodiment, the axial direction of the oil-cooled motor, the axial direction of the rotor core, and the axial direction of the rotor shaft all refer to the same direction; the circumferential direction of the oil-cooled motor, the circumferential direction of the rotor core, and the circumferential direction of the rotor shaft all refer to the same direction; and the radial direction of the oil-cooled motor, the radial direction of the rotor core, and the radial direction of the rotor shaft all refer to the same direction. For ease of understanding, the axial direction of the oil-cooled motor 100 is represented by the letter A, and the radial direction of the oil-cooled motor 100 is represented by the letter R.

[0054] Figure 4a shows the structure of the rotor 10 in one embodiment of this application, and Figure 4b is an exploded view of the rotor. The structure of the rotor 10 can be understood by referring to Figures 4a and 4b.

[0055] As shown in Figure 4a, the rotor 10 includes a rotor shaft 1, a rotor core 2, and two end plates 3. Along the axial direction of the oil-cooled motor, the two end plates 3 are arranged on both sides of the rotor core 2. The rotor shaft 1 can pass through one end plate 3, the rotor core 2, and the other end plate 3 in sequence. The rotor core 2 and the two end plates 3 can be fixed to the rotor shaft 1 via keyway engagement. One end of the rotor shaft 1 is a power output end S, which is used to connect to a reducer.

[0056] In some embodiments, the oil cooling circuit of the rotor 10 includes an oil inlet channel 11 and a plurality of oil outlet holes 31. The oil inlet channel 11 is distributed inside the rotor shaft 1 and is used to deliver cooling oil into the rotor core 2. The plurality of oil outlet holes 31 are used to discharge the cooling oil inside the rotor 10. The plurality of oil outlet holes 31 are oil spray ports at both ends of the rotor 10 for oil injection.

[0057] Referring to Figures 4b and 4c, for ease of description, the end plate 3 closer to the power output end S is designated as the second end plate 3b, and the end plate 3 farther from the power output end S is designated as the first end plate 3a. In one embodiment, the plurality of oil outlet holes include a plurality of first oil outlet holes 31a and a plurality of second oil outlet holes 31b, which are used for oil outlet at both ends of the rotor 10, respectively. Each first oil outlet hole 31a and each second oil outlet hole 31b is different, resulting in different oil spray states when the cooling oil of the rotor 10 is sprayed at both ends. This satisfies the different heat dissipation requirements at both ends of the stator winding 202, improving the heat dissipation efficiency of the oil-cooled motor 100. The oil spray state here includes at least one of the following: flow rate, direction, spray rate, spray distance, and spray angle.

[0058] In one embodiment, the plurality of first oil outlet holes 31a are spaced apart along the circumference of the oil-cooled motor on the side of the first end plate 3a away from the rotor core 2, and the plurality of second oil outlet holes 31b are spaced apart along the circumference of the oil-cooled motor on the side of the second end plate 3b away from the rotor core 2. Cooling oil inside the rotor 10 can be ejected from the side of the first end plate 3a away from the rotor core 2 through the plurality of first oil outlet holes 31a, and cooling oil inside the rotor 10 can be ejected from the side of the second end plate 3b away from the rotor core 2 through the plurality of second oil outlet holes 31b.

[0059] In some embodiments, the area of ​​each first oil outlet 31a is different from the area of ​​each second oil outlet 31b. The area of ​​a first oil outlet 31a is the area of ​​its orthographic projection along the axial direction of the oil-cooled motor onto the rotor core 2, and the area of ​​a second oil outlet 31b is the area of ​​its orthographic projection along the axial direction of the oil-cooled motor onto the rotor core 2. The difference between the areas of each first oil outlet 31a and each second oil outlet 31b affects the amount and flow rate of the cooling oil, thereby changing the oil injection state at both ends of the rotor 10.

[0060] In some embodiments, the distance between each first oil outlet 31a and the inner circumferential surface of the stator 20 along the radial direction of the oil-cooled motor is different from the distance between each second oil outlet 31b and the inner circumferential surface of the stator 20 along the radial direction of the oil-cooled motor. Taking the inner circumferential surface of the stator 20 as a reference, during the high-speed rotation of the rotor 10, the cooling oil in the rotor 10 is concentrated towards the outer circumference of the rotor 10 due to the centripetal force during the flow process. The difference between the distance between each first oil outlet 31a and the inner circumferential surface of the stator 20 along the radial direction of the oil-cooled motor and the distance between each second oil outlet 31b and the inner circumferential surface of the stator 20 along the radial direction of the oil-cooled motor can affect the order and amount of cooling oil entering the first oil outlet 31a and the second oil outlet 31b in the rotor 10, thereby changing the oil injection state at both ends of the rotor 10.

[0061] Of course, based on the basic structure of the oil-cooled motor 100 provided in this application embodiment, adaptive changes to any one or more structures in the cooling oil circuit can alter the oil outlet state at both ends of the rotor 10, thereby meeting the different cooling requirements at both ends of the stator winding 202. The above-mentioned differentiated design schemes for the first oil outlet 31a and the second oil outlet 31b provided in this application embodiment are merely illustrative examples of two schemes. The above two schemes can be implemented individually, in combination, or in combination with at least one other structural improvement of the rotor core 2 and the two end plates 3, ultimately meeting the requirement of different oil outlet states at both ends of the rotor 10.

[0062] In some embodiments, the rotor core 2, the first end plate 3a, and the second end plate 3b are fixed to the rotor shaft 1 by two fasteners 4 along the axial direction of the oil-cooled motor. One fastener 4 is arranged along the axial direction of the oil-cooled motor on the side of the first end plate 3a opposite to the rotor core 2, and the other fastener 4 is arranged along the axial direction of the oil-cooled motor on the side of the second end plate 3b opposite to the rotor core 2. The two fasteners 4 can limit and fix the rotor core 2, the first end plate 3a, and the second end plate 3b along the axial direction of the oil-cooled motor. As a specific example, referring to Figures 4b and 4c, one of the fasteners 4 is a first fastener 4a, which is arranged along the axial direction of the oil-cooled motor on the side of the first end plate 3a opposite to the rotor core 2. The other fastener 4 is a second fastener 4b, which is arranged along the axial direction of the oil-cooled motor on the side of the second end plate 3b opposite to the rotor core 2.

[0063] In one embodiment, along the radial direction of the oil-cooled motor, the distance between the outer diameter of the first fixing member 4a and the axis of the rotor 10 is less than or equal to the distance between the first oil outlet 31a and the axis of the rotor 10. The first fixing member 4a will not obstruct the first oil outlet 31a, ensuring that cooling oil can be smoothly ejected from the first oil outlet 31a. Similarly, along the radial direction of the oil-cooled motor, the distance between the outer diameter of the second fixing member 4b and the axis of the rotor 10 is less than or equal to the distance between the second oil outlet 31b and the axis of the rotor 10. The second fixing member 4b will not obstruct the second oil outlet 31b, ensuring that cooling oil can be smoothly ejected from the second oil outlet 31b.

[0064] In one embodiment, the first fixing member 4a is an annular structure, which is used to fix the rotor shaft 1 by friction.

[0065] In one embodiment, the second fixing member 4b is part of the rotor shaft 1 and has an integral structure with the rotor shaft 1. Specifically, the second fixing member 4b is an annular shoulder protruding from the outer peripheral surface of the rotor shaft 1.

[0066] In some embodiments, referring to Figures 4b and 4c, the rotor core 2 includes a plurality of rotor laminations 21 and a plurality of sets of magnets 22 assembled on the plurality of rotor laminations 21. The plurality of sets of magnets 22 are arranged at intervals along the circumference of the oil-cooled motor to form a magnetic field for coupling with the magnetic field formed by the stator windings 202, thereby driving the rotor 10 to rotate. The plurality of rotor laminations 21 are arranged adjacent to each other along the axial direction of the oil-cooled motor to form the cylindrical main structure of the rotor core 2. Each rotor lamination 21 includes a plurality of cooling holes 211, and the cooling holes 211 included in the plurality of rotor laminations 21 can be connected according to a set path to form a channel for the flow of cooling oil.

[0067] In one embodiment, each rotor lamination 21 includes a first central hole k1 extending through the rotor lamination 21 along the axial direction of the oil-cooled motor, the first central hole k1 being for the rotor shaft 1 to pass through and be fixed. The first central holes k1 of a plurality of rotor laminations 21 are sequentially connected along the axial direction of the oil-cooled motor to form a channel for the rotor shaft 1 to pass through. A first end plate 3a includes a second central hole k2 extending through the end plate 3 along the axial direction of the oil-cooled motor, and a second end plate 3b includes a second central hole k2 extending through the end plate 3 along the axial direction of the oil-cooled motor, each second central hole k2 being for the rotor shaft 1 to pass through. Similarly, a first fixing member 4a includes a third central hole k3 extending through the first fixing member 4a along the axial direction of the oil-cooled motor, the third central hole k3 also being for the rotor shaft 1 to pass through. Each first center hole k1 and each second center hole k2 has an axial protrusion t2 on its inner circumferential surface, and a corresponding axial groove t1 on the outer circumferential surface of the rotor shaft 1. The circumferential length of the axial protrusion t2 along the circumferential direction of the oil-cooled motor is less than the circumferential length of the axial groove t1, and the radial height of the axial protrusion t2 along the radial direction of the oil-cooled motor is less than the radial height of the axial groove t1. Along the axial direction of the oil-cooled motor, the axial length of the axial groove t1 is greater than the overall axial length of the stacked rotor laminations 21, and the axial groove t1 is used to accommodate the axial protrusions t2 of the multiple rotor laminations 21. When the multiple rotor laminations 21 are driven by the magnetic field formed by the stator winding 202, the rotation of the multiple rotor laminations 21 can be transmitted to the rotor shaft 1 through the keyway cooperation between the axial protrusion t2 and the axial groove t1, thereby driving the rotor shaft 1 to rotate and ultimately outputting power from the power output end S.

[0068] In some embodiments, the fit between each rotor lamination 21 and the rotor shaft 1 can be achieved through two sets of keyway structures. Specifically, the inner circumferential surface of the first central hole k1 of each rotor lamination 21 includes two axial protrusions t2, which are arranged at intervals along the circumferential direction of the oil-cooled motor. Correspondingly, the outer circumferential surface of the rotor shaft 1 includes two axial grooves t1, which are arranged at intervals along the circumferential direction of the oil-cooled motor. Each axial groove t1 is used to accommodate one axial protrusion t2 of each rotor lamination 21 along the axial direction of the oil-cooled motor, thereby strengthening the radial fit between the rotor lamination 21 and the rotor shaft 1 and also facilitating the balancing of the circumferential stress distribution of the rotor 10 during rotation. In one embodiment, the two axial protrusions t2 of each rotor lamination 21 are arranged symmetrically with reference to the axial direction of the oil-cooled motor 100, and correspondingly, the two axial grooves t1 of the rotor shaft 1 are arranged symmetrically with reference to the axial direction of the oil-cooled motor 100.

[0069] In one embodiment, the axial groove t1 of the rotor shaft 1 is also used to accommodate a portion of the axial protrusion t2 of the first end plate 3a and a portion of the axial protrusion t2 of the second end plate 3b, so that the rotor shaft 1 can drive the two end plates 3 to rotate together, and the two end plates 3 maintain synchronous rotation with the multiple rotor laminations 21.

[0070] Referring to Figures 4a to 4c, during assembly, the second end plate 3b, multiple rotor laminations 21, and the first end plate 3a are fitted onto the outer circumferential surface of the rotor shaft 1 along the axial direction of the oil-cooled motor. The outer circumferential surface of the rotor shaft 1 mates with the first central hole k1 of each rotor lamination 21 and the second central hole k2 of each end plate 3. The axial protrusion t2 of each first central hole k1 and the axial protrusion t2 of each second central hole k2 can be embedded into the axial groove t2 of the rotor shaft 1 along the axial direction of the oil-cooled motor. After the multiple rotor laminations 21 and the two end plates 3 are assembled, the side of the second end plate 3b away from the multiple rotor laminations 21 abuts against the second fixing member 4b. The first fixing member 4a is fitted onto the side of the rotor shaft 1 away from the power output end S along the axial direction of the oil-cooled motor. The first fixing member 4a is pressed and fixed to the side of the first end plate 3a away from the multiple rotor laminations 21. The first fixing member 4a and the second fixing member 4b provide axial limiting for the multiple rotor laminations 21 and the two end plates 3 along the axial direction of the oil-cooled motor.

[0071] The rotor laminations 21 are generally made of steel sheets, and the outer surface of the combined rotor laminations 21 is relatively smooth. In one embodiment, as shown in Figures 5a and 5b, the rotor 10 also includes a rotor sleeve 5 fitted around the outer periphery of the rotor core 2. In one embodiment, the rotor sleeve 5 wraps around the rotor core 2 along the circumferential direction of the oil-cooled motor. Along the axial direction of the oil-cooled motor, the axial length of the rotor sleeve 5 is greater than the axial length of the rotor core 2, and the two ends of the rotor sleeve 5 are fitted onto the outer periphery of the first end plate 3a and the second end plate 3b.

[0072] In one embodiment, the rotor sleeve 5 is made of carbon fiber and includes multiple carbon fibers wound around the outer peripheral surface of multiple rotor laminations 21 to form a carbon fiber sleeve. The carbon fiber winding around the outer peripheral surface of the multiple rotor laminations 21 can better even out the stress on the rotor 10, improving the lifespan of the rotor 10. The carbon fiber sleeve also enhances the sealing effect on the outer peripheral surface of the rotor 10, preventing cooling oil in the cooling channels within the rotor core 2 from leaking to the outer periphery of the rotor 10 and entering between the stator 20 and the rotor 10. This reduces frictional losses during rotor rotation and improves the reliability of the oil-cooled motor 100. In one embodiment, the distance between each first oil outlet 31a and the outer peripheral surface of the rotor 10 is smaller than the distance between each second oil outlet 31b and the outer peripheral surface of the rotor 10. When rotor 10 rotates, the cooling oil inside rotor 10 concentrates towards the outer circumferential surface of rotor 10 due to centripetal force. The cooling oil in rotor 10 more easily enters the first oil outlet 31a. The first oil outlet 31a has priority over the second oil outlet 31b in receiving cooling oil from rotor core 2, resulting in a difference in the oil outlet state at both ends of rotor 10. As shown in Figure 6a, a simplified cross-sectional diagram of rotor 10, the distance between the first oil outlet 31a and the outer circumferential surface of rotor 10 is h11, and the distance between the second oil outlet 31b and the outer circumferential surface of rotor 10 is h21, where h11 is less than h21. It can be considered that the first oil outlet 31a is closer to the outer circumferential surface of rotor 10 than the second oil outlet 31b.

[0073] It should be understood that the outer circumferential surface of the rotor 10 may have different outer diameters. The reference for comparing the first oil outlet 31a and the second oil outlet 31b is the outer circumferential surface of the rotor 10 at the same position, which is parallel to the inner circumferential surface of the stator 20. In subsequent embodiments, when the outer circumferential surface of the rotor 10 is used as the reference for distance comparison, it refers to the outer circumferential surface of the rotor 10 at the same position with the same radial dimension.

[0074] As shown in Figure 6a, in one embodiment, the side of the first end plate 3a facing the rotor core 2 includes multiple first oil inlets 32a, and the side of the second end plate 3b facing the rotor core 2 includes multiple second oil inlets 32b. Each first oil inlet 32a is connected to a first oil outlet 31a, and each second oil inlet 32b is connected to a second oil outlet 31b. For ease of understanding, the first end plate 3a includes a first oil outlet channel d31 connecting the first oil outlet 31a and the first oil inlets 32a, and the first oil outlet channel d31 connects the two end faces of the first end plate 3a. The second end plate 3b includes a second oil outlet channel d32 connecting the second oil outlet 31b and the second oil inlet 32b, and the second oil outlet channel d32 connects the two end faces of the second end plate 3b. Cooling oil in the rotor core 2 can pass through the first oil outlet channel d31 and be sprayed out through the first oil outlet 31a, and cooling oil in the rotor core 2 can pass through the second oil outlet channel d32 and be sprayed out through the second oil outlet 31b.

[0075] In one embodiment, the area of ​​each first oil inlet 32a is larger than the area of ​​each second oil inlet 32b. Therefore, the amount of cooling oil entering the first oil inlet 32a in the rotor 10 will be greater than the amount entering the second oil inlet 32b, thereby affecting the oil outlet state of the first oil outlet 31a and the second oil outlet 31b.

[0076] In one embodiment, as shown in FIG6a, along the radial direction of the oil-cooled motor, the distance h12 between each first oil inlet 32a and the outer peripheral surface of the rotor 10 is equal to the distance h11 between each first oil outlet 31a and the outer peripheral surface of the rotor 10. When the rotor 10 rotates, the cooling oil concentrates towards the side of the first oil outlet channel d31 near the outer peripheral surface of the rotor 10 due to the centripetal force. The direction of the cooling oil flowing from the first oil inlet 32a to the first oil outlet 31a is parallel to the axial direction of the oil-cooled motor. Taking the first oil outlet channel d31 as a reference, the axis of the first oil outlet channel d31 is parallel to the axial direction of the oil-cooled motor, which can limit the spray direction of the cooling oil discharged through the first oil outlet channel d31, so that the direction of the cooling oil sprayed from the first oil outlet 31a is parallel to the axial direction of the oil-cooled motor.

[0077] Similarly, the distance h22 between each second oil inlet 32b and the outer peripheral surface of the rotor 10 is equal to the distance h21 between each second oil outlet 31b and the outer peripheral surface of the rotor 10. When the rotor 10 rotates, the cooling oil concentrates towards the side of the second oil outlet channel d32 closest to the outer peripheral surface of the rotor 10 due to centripetal force. The direction of the cooling oil flowing from the second oil inlet 32b to the second oil outlet 31b is parallel to the axial direction of the oil-cooled motor. Using the second oil outlet channel d32 as a reference, the axis of the second oil outlet channel d32 is parallel to the axial direction of the oil-cooled motor. This allows for the limitation of the spray direction of the cooling oil exiting through the second oil outlet channel d32, ensuring that the direction of the cooling oil sprayed from the second oil outlet 31b is parallel to the axial direction of the oil-cooled motor.

[0078] In one embodiment, as shown in FIG6b, along the radial direction of the oil-cooled motor, the distance h12 between each first oil inlet 32a and the outer peripheral surface of the rotor 10 is greater than the distance h11 between each first oil outlet 31a and the outer peripheral surface of the rotor 10. When the rotor 10 rotates, the cooling oil concentrates towards the side of the first oil outlet channel d31 near the outer peripheral surface of the rotor 10 due to the centripetal force. The direction of the cooling oil flowing from the first oil inlet 32a to the first oil outlet 31a tends to be inclined outward along the radial direction of the oil-cooled motor. Taking the first oil outlet channel d31 as a reference, the axis of the first oil outlet channel d31 forms an angle with the axis of the oil-cooled motor, which can limit the spray direction of the cooling oil discharged through the first oil outlet channel d31, so that the direction of the cooling oil sprayed from the first oil outlet 31a is inclined outward along the radial direction of the oil-cooled motor.

[0079] Similarly, the distance h22 between each second oil inlet 32b and the outer peripheral surface of the rotor 10 is greater than the distance h21 between each second oil outlet 31b and the outer peripheral surface of the rotor 10. When the rotor 10 rotates, the cooling oil concentrates towards the side of the second oil outlet channel d32 closest to the outer peripheral surface of the rotor 10 due to centripetal force. The direction of the cooling oil flowing from the second oil inlet 32b to the second oil outlet 31b tends to be radially outward along the oil-cooled motor. Taking the second oil outlet channel d32 as a reference, the axis of the second oil outlet channel d32 forms an angle with the axis of the oil-cooled motor, which can limit the spray direction of the cooling oil discharged through the second oil outlet channel d32, making the direction of the cooling oil sprayed from the second oil outlet 31b radially outward along the oil-cooled motor. In one embodiment, the cross-sectional shape of any part of the first oil outlet channel d31 perpendicular to the axis of the oil-cooled motor can be the same or different, and the cross-sectional shape of any part of the second oil outlet channel d32 perpendicular to the axis of the oil-cooled motor can be the same or different. The shape change of the first oil outlet channel d31 can affect the flow direction and flow rate of the cooling oil.

[0080] In one embodiment, the area of ​​each first oil outlet 31a is larger than the area of ​​each second oil outlet 31b, which is beneficial to make the oil output of the first oil outlet 31a greater than that of the second oil outlet 31b. Of course, the oil output of the first oil outlet 31a and the second oil outlet 31b are also related to the amount of oil supplied by the rotor core 2 to the first oil outlet 31a and the second oil outlet 31b.

[0081] In one embodiment, as shown in the simplified cross-sectional diagram of a rotor 10 in FIG7, the oil cooling circuit of the rotor 10 further includes multiple radial flow channels d22 and multiple axial flow channels d21. Each radial flow channel d22 is used to connect the oil inlet channel 11 and an axial flow channel d21. Along the axial direction of the oil-cooled motor, the distance s1 between each radial flow channel d22 and the first oil outlet 31a is greater than the distance s2 between each radial flow channel d22 and the second oil outlet 31b. The time for the cooling oil supplied to the rotor 10 by the radial flow channel d22 to flow to the first oil outlet 31a can be shorter than the time for the cooling oil to flow to the second oil outlet 31b, which can make the oil output of the rotor 10 on the second oil outlet 31b side different from the oil output on the first oil outlet 31a side.

[0082] In one embodiment, referring to Figure 7, with the structure of the rotor core 2 as a reference, the rotor core 2 includes a first core end face a1 and a second core end face a2. Each axial flow channel d21 includes a first opening d211 and a second opening d212 opposite to each other along the axial direction of the oil-cooled motor. The first opening d211 of each axial flow channel d21 is distributed on the first core end face a1, and the second opening d212 of each axial flow channel d21 is distributed on the second core end face a2. Each first opening d211 is used to discharge cooling oil through a first oil outlet 31a. During the rotation of the rotor 10, the cooling oil inside the rotor 10 is concentrated towards the outer peripheral surface of the rotor 10 due to centrifugal force.

[0083] In some embodiments, the distance h01 between the first opening d211 in the radial direction of the oil-cooled motor and the outer peripheral surface of the rotor 10 is greater than the distance h11 between the first oil outlet 31a and the outer peripheral surface of the rotor 10. It can be assumed that there is a height difference in the radial direction of the oil-cooled motor between the first opening d211 of the axial flow channel d21 and the first oil outlet 31a. When the cooling oil in the axial flow channel d21 is concentrated on the side of the axial flow channel d21 near the outer peripheral surface of the rotor 10 due to centrifugal force, the cooling oil can be smoothly transmitted through the first opening d211 to the first oil outlet 31a and ejected.

[0084] In some embodiments, the distance h02 between the second radial opening d212 of the oil-cooled motor and the outer peripheral surface of the rotor 10 is less than the distance h21 between the second oil outlet 31b and the outer peripheral surface of the rotor 10. It can be considered that there is a radial height difference between the second opening d212 of the axial flow channel d21 and the second oil outlet 31b. When the cooling oil in the axial flow channel d21 is concentrated on the side of the axial flow channel d21 near the outer peripheral surface of the rotor 10 due to centrifugal force, the cooling oil in the axial flow channel d21 needs to reach a certain liquid level before it can flow to the second oil outlet 31b.

[0085] In one embodiment, as shown in FIG7, in the rotor 10, the first opening d211 of each axial flow channel d21 is connected to the first oil outlet 31a, and the first opening d212 of each axial flow channel d21 is connected to the second oil outlet 31b. Each axial flow channel d21 receives cooling oil from the oil inlet channel 11 of the rotor shaft 1 through a radial flow channel d22, and the cooling oil in each axial flow channel d21 is ejected through the first oil outlet 31a and the second oil outlet 31b respectively.

[0086] In one embodiment, the axial flow channel d21 serves as a reference, and its axis is parallel to the axis of the rotor 10. The distance between any point along the axial direction of the oil-cooled motor and the outer circumferential surface of the rotor 10 is equal. Specifically, along the axial direction of the oil-cooled motor, one end of the axial flow channel d21 is connected to a first oil outlet 31a via a first oil outlet channel d31, and the other end is connected to a second oil outlet 31b via a second oil outlet channel d32. The cooling oil in the axial flow channel d21 can flow along the axial direction of the oil-cooled motor and be ejected from the first oil outlet 31a and the second oil outlet 31b, respectively.

[0087] Referring to Figure 7, in one embodiment, the distance between the first oil inlet 32a and the outer peripheral surface of the rotor 10 is less than the distance between the first opening d211 and the outer peripheral surface of the rotor 10. A step is formed between the axial flow channel d21 and the first oil outlet channel d31, and this step is located radially closer to the outer peripheral surface of the rotor 10. The cooling oil present in the axial flow channel d21 flows towards the end closer to the first end plate 3a and can then enter the first oil outlet channel d31 and be ejected through the first oil outlet hole 31a.

[0088] In one embodiment, the distance between the second oil inlet 32b and the outer peripheral surface of the rotor 10 is greater than the distance between the second opening d212 and the outer peripheral surface of the rotor 10. A step is formed between the axial flow channel d21 and the second oil outlet channel d32, and this step is located radially away from the outer peripheral surface of the rotor 10. When the rotor 10 rotates at high speed, the cooling oil in the axial flow channel d21 accumulates on the side of the axial flow channel d21 near the outer peripheral surface under the action of centrifugal force. When the oil level in the axial flow channel d21 reaches the position of the second opening d212 along the radial direction of the oil-cooled motor, the cooling oil can enter the second oil outlet channel d32 and be ejected through the second oil outlet hole 31b. That is, the cooling oil will only enter the second oil outlet channel d32 and be ejected through the second oil outlet hole 31b when the oil level in the axial flow channel d21 plus the distance between the axial flow channel d21 and the outer peripheral surface of the rotor 10 is greater than the distance between the second opening d212 and the outer peripheral surface of the rotor 10.

[0089] In one embodiment, the area of ​​each first oil outlet 31a is greater than or equal to the area of ​​each first opening d211, and the area of ​​each second oil outlet 31b is less than the area of ​​each second opening d212. Cooling oil within the axial flow channel d21 can more easily and in greater quantity enter the first oil outlet channel d31 and be ejected through the first oil outlet 31a.

[0090] In one embodiment, based on the structure where both ends of an axial flow channel d21 are connected to a first oil outlet 31a and a second oil outlet 31b respectively, the communication area between the axial flow channel d21 and the first oil outlet 31a is greater than the communication area between the axial flow channel d21 and the second oil outlet 31b. Specifically, the communication area between the axial flow channel d21 and the first oil outlet channel d31 is greater than the communication area between the axial flow channel d21 and the second oil outlet channel d32, making it easier and more abundant for the cooling oil in the axial flow channel d21 to enter the first oil outlet channel d31 and be ejected through the first oil outlet 31a.

[0091] In one embodiment, as shown in FIG8, the rotor core 2 includes a plurality of rotor laminations 21, which are arranged adjacently along the axial direction of the oil-cooled motor to form the rotor core 2. Each rotor lamination 21 includes a plurality of cooling holes 211. When the plurality of rotor laminations 21 are arranged adjacently along the circumferential direction of the oil-cooled motor, the plurality of cooling holes 211 of each rotor lamination 21 can be connected to the plurality of cooling holes 211 of adjacent rotor laminations 21 to form the plurality of axial flow channels d21. The plurality of cooling holes 211 of one rotor lamination 21 are connected to the plurality of cooling holes 211 of adjacent rotor laminations 21 in a one-to-one correspondence. One or more of the plurality of radial flow channels d22 in the oil cooling circuit of the rotor 10 are formed by a structure on one rotor lamination 21, that is, one rotor lamination 21 includes one or more of the plurality of radial flow channels d22. For the rotor lamination 21, one end of each radial flow channel d22 is connected to a cooling hole 211, and the other end is connected to the center hole of the rotor lamination 21, so as to receive the cooling oil transmitted from the rotor shaft 1 and deliver it to an axial flow channel d21.

[0092] In one embodiment, as illustrated in Figure 9, a simplified cross-sectional structure of a rotor 10 is provided. Each radial flow channel d31 is used to supply cooling oil to a second opening d212 and a second oil outlet 31b. The distance h02 between each second opening d212 and the outer peripheral surface of the rotor 10 is less than or equal to the distance h21 between each second oil outlet 31b and the outer peripheral surface of the rotor 10. Each radial flow channel d31 is used to divert the cooling oil in the oil inlet channel 11 of the rotor shaft 1 to an axial flow channel d21 and a second oil outlet 31b, thus the rotor 10 is effectively equipped with unilateral oil inlet.

[0093] In one embodiment, along the radial direction of the oil-cooled motor, the distance h3 between each radial flow channel d22 and the outer peripheral surface of the rotor 10 is smaller than the distance h02 between the second opening d212 and the outer peripheral surface of the rotor 10, and smaller than the distance h21 between the second oil outlet 31b and the outer peripheral surface of the rotor 10. There is a height difference between the radial flow channel d22 and the second opening d212 and the second oil outlet 31b along the radial direction of the oil-cooled motor. Under the action of the centrifugal force of the rotor 10 rotation, the radial flow channel d22 can have a certain reserve function for cooling oil.

[0094] In one embodiment, along the radial direction of the oil-cooled motor, the height difference between the radial flow channel d22 and the second opening d212 is less than the height difference between the radial flow channel d22 and the second oil outlet 31b, that is, the difference between h02 and h3 is less than the difference between h21 and h3. Under the centrifugal force of the rotating rotor 10, the cooling oil in the radial flow channel d can flow to the second opening d212 before the second oil outlet 31b.

[0095] In one embodiment, the radial flow channel d22 is a part of the structure of the second end plate 3b. The radial flow channel d22 communicates with a second opening d212 of an axial flow channel d21 and a second oil outlet 31b along the axial direction of the oil-cooled motor. Figure 10a shows the structure of a second end plate 3b, and Figure 10b is a schematic cross-sectional view of the second end plate 3b. Referring to Figures 10a and 10b together, the second end plate 3b includes a plurality of radial grooves d33, a plurality of second oil outlet channels d32, and a plurality of second oil outlet holes 31b. Each radial groove d33 serves as a radial flow channel d22, and each radial groove d33 communicates an axial flow channel d21 and a second oil outlet hole 31b.

[0096] Specifically, the end face of the second end plate 3b facing away from the rotor core 2 includes a plurality of second oil outlet holes 31b, which are arranged at intervals along the circumference of the oil-cooled motor. The end face of the second end plate 3b facing the rotor core 2 includes a plurality of radial grooves d33, which are arranged at intervals along the circumference of the oil-cooled motor. Each second oil outlet channel d32 connects to a radial groove d33. Along the radial direction of the oil-cooled motor, one end of the radial groove d33 communicates with the second center hole k2 of the second end plate 3b. Each radial groove d33 has the same shape, and the second oil outlet holes 31b are exemplified by circular holes.

[0097] In one embodiment, along the radial direction of the oil-cooled motor, the distance between the end of the radial groove d33 near the outer peripheral surface of the second end plate 3b and the second central hole k2 is greater than the distance between the end of the second oil outlet hole 31b near the outer peripheral surface of the second end plate 3b and the second central hole k2. The radial groove d33 serves as a radial flow channel to supply oil to the axial flow channel d21. Along the circumference of the oil-cooled motor, the circumferential width of the radial groove d33 is greater than the circumferential width of the connected second oil outlet hole 31b and less than the circumferential width of the connected axial flow channel d21. The amount of cooling oil in the radial groove d33 is sufficient to supply the first oil outlet hole 31a and the second oil outlet hole 31b. For a set of connected second oil outlet holes 31b and radial groove d33, along the axial direction of the oil-cooled motor, the orthographic projection of the radial groove d33 on any end face of the second end plate 3b covers the orthographic projection of the corresponding second oil outlet hole 31b on that end face, which is beneficial for the cooling oil in the radial groove d33 to meet the oil injection cooling requirements.

[0098] Figure 11a shows a cross-sectional structure of a rotor 10 having the second end plate 3b shown in Figures 10a and 10b. The oil inlet channel 11 of the rotor shaft 1 specifically includes multiple axial channels d11 and multiple radial channels d12. The axial channels d11 penetrate the rotor shaft 1 along the axial direction of the oil-cooled motor, and each radial channel d12 connects the outer circumferential surface of the rotor shaft 1 to the axial channel d11 along the radial direction of the oil-cooled motor. The multiple radial channels d12 are arranged at intervals along the circumference of the oil-cooled motor. Multiple cooling holes 211 of multiple rotor laminations 21 of the rotor core 2 are respectively connected along the axial direction of the oil-cooled motor to form multiple axial flow channels d21. Each axial flow channel d21 penetrates the entire rotor core 2 along the axial direction of the oil-cooled motor, and the two openings of each axial flow channel d21 are located at the two core end faces of the rotor core 2. The first end plate 3a includes multiple first oil outlet channels d31 and multiple first oil outlet holes 31a. The end face of the first end plate 3a facing away from the rotor core 2 includes the aforementioned first oil outlet holes 31a. The multiple first oil outlet holes 31a are arranged at intervals along the circumference of the oil-cooled motor. Each first oil outlet channel d31 connects a first oil outlet hole 31a to the end face of the first end plate 3a facing the rotor core 2. The second end plate 3b includes multiple radial grooves d33, multiple second oil outlet channels d32, and multiple second oil outlet holes 31b. The end face of the second end plate 3b facing away from the rotor core 2 includes the aforementioned multiple second oil outlet holes 31b. The multiple second oil outlet holes 31b are arranged at intervals along the circumference of the oil-cooled motor. Each radial groove d33 is formed on the end face of the second end plate 3b facing the rotor core 2. The multiple radial grooves d33 are arranged at intervals along the circumference of the oil-cooled motor. Each second oil outlet channel d32 connects a second oil outlet hole 31b and a radial groove d33 along the circumference of the oil-cooled motor. Each radial groove d33 connects to a radial channel d12 of the rotor shaft 1 along the radial direction of the oil-cooled motor. Each radial groove d33 serves as a radial flow channel d22 of the oil cooling circuit of the rotor 10, receiving the cooling oil from the rotor shaft 1 and conveying it to an axial flow channel d21 and a second oil outlet channel d32. The distribution of multiple radial grooves d33 and multiple axial flow channels d21 can distribute the cooling oil from the rotor shaft 1 more evenly along the circumference of the oil-cooled motor, preventing hot spots caused by uneven circumferential distribution of cooling oil within the rotor 10, thus improving the stability of the rotor 10 and optimizing the performance of the oil-cooled motor 100.

[0099] With reference to the entire rotor 10 structure, each axial flow channel d21 is connected to the axial channel d11 via a radial groove d33 and a radial channel d12, thereby receiving the cooling oil delivered from the rotor shaft 1. Each radial groove d33 is connected to an axial flow channel d21 and a second oil outlet channel d32 along the axial direction of the oil-cooled motor, which can deliver the cooling oil to a first oil outlet hole 31a and a second oil outlet hole 31b for spraying.

[0100] Figure 11b shows a partial structure of the rotor 10 in Figure 11a, specifically including the second end plate 3b, the rotor core 2, and the rotor shaft 1. As shown in Figure 11b, a radial groove d33 connects an axial flow channel d21 and a second oil outlet channel d32 along the axial direction of the oil-cooled motor. The radial groove d33 also connects to a radial channel d12 along the radial direction of the oil-cooled motor. Along the radial direction of the oil-cooled motor, the distance between the radial groove d33 and the outer peripheral surface of the rotor 10 is less than the distance between the axial flow channel d21 and the outer peripheral surface of the rotor 10, the distance between the second oil outlet channel d32 and the outer peripheral surface of the rotor 10, and the distance between the second oil outlet hole 31b and the outer peripheral surface of the rotor 10. Steps are formed between the radial groove d33 and the axial flow channel d21 and the second oil outlet channel d32, respectively, with both steps close to the outer peripheral surface of the rotor 10. When the cooling oil delivered from the rotor shaft 1 through the axial channel d11 and radial channel d12 enters the radial groove d33, the cooling oil accumulates towards the outer peripheral surface of the rotor 10 under the action of centripetal force. The end of the radial groove d33 near the outer peripheral surface of the rotor 10 can store the cooling oil. At least one of the following parameters—oil quantity, flow rate, time, and angle—is different between the cooling oil delivered through the radial groove d33 to the axial flow channel d21 and the second oil outlet channel d32. Combined with the different areas of the first oil outlet hole 31a and the second oil outlet hole 31b, the different distances between the first oil outlet hole 31a and the outer peripheral surface of the rotor 10, and the different distances between the second oil outlet hole 31b and the outer peripheral surface of the rotor 10, the cooling oil ejected from the first oil outlet hole 31a and the second oil outlet hole 31b ultimately differs in at least one of the following parameters—oil quantity, flow rate, time, and angle—to meet the different oil cooling requirements of the windings at both ends of the stator 20.

[0101] In some embodiments, as shown in FIG12, the second end plate 3b includes an annular groove d34. The annular groove d34 is used to surround and connect the plurality of radial grooves d33. The annular groove d34 can receive the cooling oil delivered by the plurality of radial grooves d33 and make the cooling oil flow along the circumference of the oil-cooled motor, further homogenizing the cooling oil circumferentially. Under the action of centripetal force, the cooling oil enters the annular groove d34 through the plurality of radial grooves d33, and then flows evenly along the circumference of the oil-cooled motor through the annular groove d34, and is supplied to the plurality of axial flow channels d21 and the plurality of second oil outlet holes 31b along the axial direction of the oil-cooled motor respectively. When the second end plate 3b shown in FIG12 is applied to the rotor shown in FIG11a, the annular groove d34 can make the cooling oil delivered by the plurality of radial grooves d33 flow along the circumference of the oil-cooled motor, improving the circumferential distribution uniformity of the oil volume, making the cooling oil entering the rotor core 2 more evenly distributed along the circumference of the oil-cooled motor, and the cooling oil sprayed from both ends of the rotor 10 also more evenly distributed along the circumference of the oil-cooled motor.

[0102] In one embodiment, along the axis of the oil-cooled motor, the axial depth of the axial flow channel d34 is the same as the axial depth of the radial groove d33, which helps to reduce the flow resistance of the cooling oil.

[0103] In one embodiment, along the radial direction of the oil-cooled motor, the distance between the annular groove d34 and the outer peripheral surface of the rotor 10 is less than or equal to the distance between each second oil outlet 31b and the outer peripheral surface of the rotor 10, and less than the distance between the second opening d212 of the axial flow channel d21 and the outer peripheral surface of the rotor 10. Cooling oil enters the annular groove d34 under the action of centrifugal force. The annular groove d34 can provide a certain oil storage function, and then distributes the cooling oil to the axial flow channel d21 and the second oil outlet 31b.

[0104] In one embodiment, the annular groove d34 communicates with two or more radial grooves d33, but not with all of the radial grooves d33. When the cooling oil flows within the annular groove d34, it achieves partial circumferential uniformity, which can meet some specific cooling requirements.

[0105] This application embodiment also provides a rotor 10, which has two or more layers of oil channels distributed radially, enabling better oil cooling effect. Figure 13 shows a cross-sectional structure of a rotor 10, which differs from the rotor 10 shown in Figure 11a in that the oil cooling circuit of this rotor 10 further includes multiple auxiliary flow channels d23. Each auxiliary flow channel d23 includes an inlet d232 and an outlet d231. The inlets d232 of the multiple auxiliary flow channels d23 are distributed circumferentially on the second iron core end face a2 along the oil cooling motor. The inlet d232 of each auxiliary flow channel d23 and the second opening d212 of an axial flow channel d21 are arranged radially on the oil cooling motor and are used to connect to the same radial flow channel d22. The outlets of the multiple auxiliary flow channels d23 are distributed circumferentially on the first iron core end face a1 along the oil cooling motor. The outlet of each auxiliary flow channel d23 and the first opening d211 of an axial flow channel are arranged radially on the oil cooling motor and are used to connect to the same first oil outlet 31a. Cooling oil from a radial flow channel d22 can enter an axial flow channel d21 and an auxiliary flow channel d23 respectively. The cooling oil in the axial flow channel d21 and the auxiliary flow channel d23 can simultaneously flow into the same first oil outlet 31a. The axial flow channel d21 and the auxiliary flow channel d23 are similar to parallel oil circuits in the oil cooling circuit, which can improve the oil cooling effect.

[0106] In one embodiment, the auxiliary flow channels d23 and axial flow channels d21, arranged radially at intervals along the oil-cooled motor, are positioned such that the distance between the auxiliary flow channel d23 and the axis of the rotor 10 is greater than the distance between the axial flow channel d21 and the axis of the rotor 10, thus forming two layers of oil-cooling channels arranged radially along the oil-cooled motor. When the auxiliary flow channel d23 is arranged radially along the oil-cooled motor between an axial flow channel d21 and the outer peripheral surface of the rotor 10, the auxiliary flow channel d23 is closer to the magnet 22 in the rotor 10, and the auxiliary flow channel d23 can better dissipate heat from the magnet 22.

[0107] In one embodiment, the area of ​​the inlet d232 of each auxiliary flow channel d23 is smaller than the area of ​​the second opening d212 of each axial flow channel d21, and the area of ​​the outlet d231 of each auxiliary flow channel d23 is smaller than the area of ​​the first opening d211 of each axial flow channel d21. The cooling oil in the auxiliary flow channel d23 is used for auxiliary oil cooling. When the auxiliary flow channels d23 are arranged radially along the oil-cooled motor between an axial flow channel d21 and the outer peripheral surface of the rotor 10, the smaller size of the auxiliary oil channels d23 can ensure the strength of the rotor core 2.

[0108] In one embodiment, as shown in FIG13, the distance between the outlet d231 of each auxiliary channel d23 and the axis of the rotor 10 is less than the sum of the distance between the first liquid outlet channel d31 connected to the auxiliary channel d23 and the axis of the rotor 10 and the radial length of the first liquid outlet channel d31, so that the auxiliary channel d23 can be connected through the first liquid outlet channel d31, thereby realizing the connection with the first liquid outlet hole 31a.

[0109] In one embodiment, the connection between the outlet d231 of each auxiliary channel d23 and the first liquid outlet 31a can also be achieved through a channel on the first end plate 3a. Specifically, the first end plate 3a includes a channel that can connect the outlet d231 of the auxiliary channel d23 with the first liquid outlet 31a.

[0110] As shown in Figure 14a, an embodiment of this application provides a partial structure of the rotor core 2 of a rotor 10, specifically including a rotor lamination 21 and a plurality of magnets 22 embedded in the rotor lamination 21. As shown in Figure 14a, the rotor lamination 21 includes a plurality of cooling holes 211 and a plurality of mounting holes 212, each cooling hole 211 and each mounting hole 212 penetrating the rotor lamination 21 along the axial direction of the oil-cooled motor. Along the circumferential direction of the oil-cooled motor, the plurality of cooling holes 211 are arranged at intervals. Each mounting hole 212 is used to embed a magnet 22.

[0111] In one embodiment, as shown in Figure 14a, a group of magnets 22 are enclosed within the elliptical dashed circle. Multiple groups of magnets 22 are arranged at intervals along the circumference of the oil-cooled motor, and one or more cooling holes 211 are arranged between any two adjacent groups of magnets 22. When cooling oil flows through the cooling holes 211, the cooling oil exchanges heat with the rotor laminations 21 through the cooling holes 211, thereby carrying away the heat generated by the magnets 22.

[0112] In one embodiment, along the radial direction of the oil-cooled motor, the distance between each cooling hole 211 and the first central hole k1 is less than the distance between each magnet 22 and the first central hole k1, which can ensure the strength of the rotor lamination 21.

[0113] In one embodiment, as shown in FIG14a, each cooling hole 211 includes two circumferential inner walls that are radially opposite each other along the oil-cooled motor. Of these two circumferential inner walls, the length of the circumferential sidewall closest to the outer circumferential surface of the rotor lamination 21 is less than the length of the axial sidewall closest to the first central hole k1. The end of the cooling hole 211 facing the outer circumferential surface of the rotor lamination 21 can be adapted to the shape of the area between two sets of adjacent magnets 22 to achieve a good cooling effect while ensuring the strength of the rotor lamination 21.

[0114] In one embodiment, as shown in Figure 14a, each cooling hole 211 further includes two radially opposing inner walls along the circumference of the oil-cooled motor. Each radially opposing inner wall is connected between the ends of the two axially opposing inner walls, and the two circumferential inner walls and the two radially opposing inner walls can enclose and form a trapezoidal cross-section cooling hole 211. To improve the flowability of the cooling oil, the connection between each set of circumferential inner walls and radially opposing inner walls is a smoothly transitioned arc surface. The radius of the arc surface can be set according to the shape of the rotor lamination 21 and the size of the cooling hole 211. In some embodiments, the radius of the arc surface at the connection between the circumferential inner wall and the radially opposing inner wall is about 1 mm.

[0115] Figure 14b illustrates another rotor lamination 21 and a plurality of magnets 22 embedded in the rotor lamination 21. The rotor lamination 21 includes a plurality of cooling holes 211, i.e., auxiliary cooling holes 213, which penetrate the rotor lamination 21 along the axial direction of the oil-cooled motor and are also used for the flow of cooling oil. Exemplarily, each cooling hole 211 is arranged with an auxiliary cooling hole 213 between it and the outer peripheral surface of the rotor lamination 21. The circumferential width of the auxiliary cooling hole 213 along the circumferential direction of the oil-cooled motor is smaller than the circumferential width of the cooling hole 211, to accommodate the space between two sets of magnets 22 arranged axially. When a plurality of rotor laminations 21 shown in Figure 14b are stacked along the circumferential direction of the oil-cooled motor to form at least a portion of the rotor core 2, the plurality of auxiliary cooling holes 213 of adjacent rotor laminations 21 can be connected in a one-to-one correspondence to form at least a portion of the auxiliary flow channel d23 in Figure 13.

[0116] The cross-sectional area of ​​the auxiliary cooling hole 213 is smaller than that of the cooling hole 211, and the cooling oil in the auxiliary cooling hole 213 is mainly used for auxiliary oil cooling.

[0117] Referring to Figures 14a and 14b, the mounting holes 212 included in the rotor laminations 21 of the rotor 10 provided in this embodiment can communicate with the cooling holes 211, allowing the cooling oil in the cooling holes 211 to enter the mounting holes 212 and directly oil cool the magnets 22 fixed within the mounting holes 212. The internal space of each mounting hole 212 is larger than the volume of the magnets 22 accommodated in that mounting hole 212, ensuring sufficient space for cooling oil after the magnets 22 are inserted. The magnets 22 can be fixed within the mounting holes 212 by adhesive bonding, interference fit, or other methods.

[0118] In summary, the oil-cooled motor 100 provided in this application embodiment has an oil-cooling circuit in its rotor 10 capable of spraying cooling oil in different states at both axial ends of the rotor 10, thereby spraying oil in different states at both ends of the stator winding 202 to meet the different heat dissipation requirements at both ends of the stator winding 202. Specifically, at least one parameter of the position, size, or shape of the oil outlet holes 31 on the two end plates 3 of the rotor 10 is different. Combined with the design of the oil-cooling circuit inside the rotor 10, the oil outlet state at both ends of the rotor 10 can be adjusted as needed to meet the different oil cooling requirements at both ends of the stator winding 202. Of course, the structural changes described in the different embodiments above can be implemented independently or in combination, as long as the final oil spray state at both ends of the rotor 10 can meet the different heat dissipation requirements of the end windings on both sides of the stator winding 202.

[0119] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An oil-cooled electric machine characterized by, The oil-cooled motor includes a stator and a rotor. The central hole of the stator is used to accommodate the rotor. The rotor includes a rotor shaft, a rotor core, a first end plate, and a second end plate. The rotor shaft passes sequentially through the first end plate, the rotor core, and the second end plate along the axial direction of the oil-cooled motor. The oil cooling circuit of the rotor includes: An oil inlet channel is provided inside the rotor shaft and is used to deliver cooling oil into the rotor core. Multiple oil outlet holes are provided for discharging cooling oil from inside the rotor. The multiple oil outlet holes include multiple first oil outlet holes and multiple second oil outlet holes. The plurality of first oil outlet holes are distributed at intervals along the circumference of the oil-cooled motor on the side of the first end plate away from the rotor core, and the plurality of second oil outlet holes are distributed at intervals along the circumference of the oil-cooled motor on the side of the second end plate away from the rotor core. At least one of the following is different: the area of ​​each first oil outlet hole and each second oil outlet hole or the distance between each first oil outlet hole and each second oil outlet hole and the inner circumferential surface of the stator along the radial direction of the oil-cooled motor.

2. The oil-cooled electric machine of claim 1, wherein, Along the radial direction of the oil-cooled motor, the distance between each of the first oil outlet holes and the outer peripheral surface of the rotor is less than the distance between each of the second oil outlet holes and the outer peripheral surface of the rotor.

3. The oil-cooled electric machine of claim 1 or 2, wherein, The area of ​​each of the first oil outlet holes is larger than the area of ​​each of the second oil outlet holes.

4. The oil-cooled motor as described in any one of claims 1-3, characterized in that, The rotor's oil cooling circuit further includes multiple radial flow channels and multiple axial flow channels, each of the radial flow channels connecting the oil inlet channel and one of the axial flow channels, wherein: Along the axial direction of the oil-cooled motor, the distance between each radial flow channel and the first oil outlet is greater than the distance between each radial flow channel and the second oil outlet.

5. The oil-cooled electric machine of claim 4, wherein, The rotor core includes a first core end face and a second core end face opposite to each other along the axial direction of the oil-cooled motor. Each axial flow channel includes a first opening and a second opening opposite to each other along the axial direction of the oil-cooled motor. The first opening of each axial flow channel is distributed on the first core end face, and the second opening of each axial flow channel is distributed on the second core end face, wherein: Along the radial direction of the oil-cooled motor, each of the first openings is used to discharge cooling oil through a first oil outlet hole, and the distance between each of the first openings and the outer peripheral surface of the rotor is greater than the distance between each of the first oil outlet holes and the outer peripheral surface of the rotor.

6. The oil-cooled electric machine of claim 5, wherein, Each of the radial flow channels is used to deliver cooling oil to one of the second openings and one of the second oil outlets, wherein: Along the radial direction of the oil-cooled motor, the distance between each of the second openings and the outer peripheral surface of the rotor is less than or equal to the distance between each of the second oil outlet holes and the outer peripheral surface of the rotor.

7. The oil-cooled electric machine of claim 6, wherein, The area of ​​each first oil outlet hole is greater than or equal to the area of ​​each first opening, and the area of ​​each second oil outlet hole is less than the area of ​​each second opening.

8. The oil-cooled electric machine of claim 4, wherein, The rotor core also includes multiple auxiliary flow channels, each of which includes an inlet and an outlet, wherein: The inlets of the plurality of auxiliary flow channels are distributed at intervals along the circumference of the oil-cooled motor on the end face of the second iron core. The inlet of each auxiliary flow channel and the second opening of an axial flow channel are arranged at intervals along the radial direction of the oil-cooled motor and are used to connect the same radial flow channel. The area of ​​the inlet of each auxiliary flow channel is smaller than the area of ​​the second opening of each axial flow channel. The outlets of the plurality of auxiliary flow channels are distributed at intervals along the circumference of the oil-cooled motor on the end face of the first iron core. The outlet of each auxiliary flow channel and the first opening of an axial flow channel are arranged at intervals along the radial direction of the oil-cooled motor and are used to connect to the same first oil outlet. The area of ​​the outlet of each auxiliary flow channel is smaller than the area of ​​the first opening of each axial flow channel.

9. An oil-cooled electric machine as claimed in any of claims 4 to 8, characterised in that, The second end plate includes a plurality of radial grooves on the side facing the rotor core. Each radial groove serves as a radial flow channel. The plurality of radial grooves are arranged at intervals along the circumference of the oil-cooled motor. Each radial groove is used to connect an axial flow channel and a second oil outlet. Along the radial direction of the oil-cooled motor, the distance between each radial groove and the outer peripheral surface of the rotor is less than the distance between the second oil outlet and the outer peripheral surface of the rotor, and the distance between the axial flow channel and the outer peripheral surface of the rotor.

10. The oil-cooled electric machine of claim 9, wherein, Along the circumference of the oil-cooled motor, the circumferential width of each radial groove is greater than the circumferential width of the connected second oil outlet hole and less than the circumferential width of the second opening of the axial flow channel.

11. The oil-cooled electric machine of claim 9 or 10, wherein, The second end plate also includes an annular groove on the side facing the rotor core, the annular groove being used to surround and connect the plurality of radial grooves, wherein: Along the radial direction of the oil-cooled motor, the distance between the annular groove and the outer peripheral surface of the rotor is less than or equal to the distance between each of the second oil outlet holes and the outer peripheral surface of the rotor, and less than the distance between the second opening of the axial flow channel and the outer peripheral surface of the rotor.

12. The oil-cooled electric machine of any one of claims 1-11, wherein, The first end plate includes a plurality of first oil inlets on the side facing the rotor core, and the second end plate includes a plurality of second oil inlets on the side facing the rotor core. Each first oil inlet is connected to a first oil outlet, and each second oil inlet is connected to a second oil outlet. The area of ​​each of the first oil inlets is larger than the area of ​​each of the second oil inlets.

13. The oil-cooled electric machine of claim 12, wherein, Along the radial direction of the oil-cooled motor, the distance between each first oil inlet and the outer peripheral surface of the rotor is greater than or equal to the distance between each first oil outlet and the outer peripheral surface of the rotor, and the distance between each second oil inlet and the outer peripheral surface of the rotor is greater than or equal to the distance between each second oil outlet and the outer peripheral surface of the rotor.

14. A powertrain, characterized by, The powertrain includes a reducer and an oil-cooled motor as described in any one of claims 1-13, wherein the oil-cooled motor is drive-connected to the reducer.

15. An electric vehicle characterized by comprising: The vehicle includes wheels and a powertrain as described in claim 14, the powertrain being used to drive the wheels.

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