Oil-cooled stator and vehicle

Abstract

The application provides an oil-cooled stator and a vehicle. The oil-cooled stator comprises a stator core, the stator core is stacked along an axial direction by a plurality of core assemblies, each core assembly is composed of a plurality of stampings, each stamping is provided with at least two oil inlet holes and a plurality of oil outlet holes in a circumferential direction, the oil inlet holes of two adjacent core assemblies are partially overlapped, and a part of the oil inlet holes is in communication with the plurality of oil outlet holes; the two adjacent core assemblies are rotated by a first angle along a stator axis to form a spiral axial staggered structure, a plurality of spiral axial staggered structures are in communication to form a cooling oil channel, and the cooling oil channel is used for continuously flowing cooling oil along a spiral path in the stator core. The technical problem that a traditional motor cooling mode has large thermal resistance, uneven heat dissipation and difficulty in matching the heat dissipation requirement of a high-power-density flat wire winding is solved.

Description

Technical Field

[0001] This invention relates to the field of vehicle motor technology, and more specifically, to an oil-cooled stator and a vehicle. Background Technology

[0002] In existing drive motor oil cooling technologies, immersion cooling oil suffers from high agitation losses and low efficiency. While traditional spray cooling can precisely spray oil to the winding ends, its oil circuit structure is simple, the path is short, the oil volume distribution is uneven, and the flow rate is slow. This makes it difficult for the cooling oil to effectively penetrate into the core heat-generating areas such as the flat copper wires and iron core in the stator slots. The heat transfer path is still relatively long, the cooling efficiency is limited, and it is easy to cause temperature change points due to uneven local cooling, which restricts the further improvement of motor power density and continuous operation capability.

[0003] There is currently no effective solution to the aforementioned technical problems. Summary of the Invention

[0004] The main objective of this invention is to provide an oil-cooled stator and vehicle to solve the technical problems of high thermal resistance, uneven heat dissipation, and difficulty in matching the heat dissipation requirements of high power density flat wire windings in traditional motor cooling methods.

[0005] To achieve the above objectives, according to one aspect of the present invention, an oil-cooled stator is provided, comprising: a stator core, the stator core being formed by stacking multiple core assemblies along the axial direction; the core assembly being formed by stacking multiple laminations, each lamination having at least two oil inlets and multiple oil outlets along the circumferential direction, the oil inlets on adjacent core assemblies partially overlapping, and a portion of the oil inlets communicating with the multiple oil outlets; adjacent core assemblies being rotated along the stator axis by a first angle to form a spiral axial misalignment structure, the multiple spiral axial misalignment structures communicating to form a cooling oil channel, the cooling oil channel being used to allow cooling oil to flow continuously along a spiral path inside the stator core.

[0006] Furthermore, each core assembly is provided with two oil inlets and multiple oil outlets along the circumferential direction. The two oil inlets are arranged symmetrically along the radial direction of the stator core, and the multiple oil outlets are evenly distributed on both sides of the two oil inlets. The oil outlets on both sides are arranged symmetrically with the center line connecting the two oil inlets as the reference.

[0007] Furthermore, the included angle between the two ends of each oil inlet hole on the same lamination is a second angle β, and the included angle between the center lines of two adjacent oil outlet holes is a third angle γ, where 11°≤β≤12° and 3.5°≤γ≤4°.

[0008] Furthermore, the first angle ranges from 7° to 8°, and twice the third angle γ equals the first angle.

[0009] Furthermore, the oil inlets of each core assembly segment located in the intermediate region form a first oil distribution path, a second oil distribution path, and a third oil distribution path for collecting cooling oil; the overlapping area of ​​a portion of the oil inlet of the current core assembly segment and the oil inlet of the next core assembly segment forms the first oil distribution path, which is used to conduct cooling oil to the next core assembly segment; the oil inlet of a portion of the current core assembly segment connects with the oil outlet of the next core assembly segment to form the second oil distribution path, which is used to directly spray cooling oil to the opposite winding end; the oil inlet of a portion of the current core assembly segment connects with the oil outlet of the previous core assembly segment to form the third oil distribution path, which is used to return cooling oil to the oil outlet of the core assembly of the previous layer.

[0010] Furthermore, the oil inlets at both ends of the core assembly form a fourth and a fifth oil distribution path for collecting cooling oil; the oil inlets of the core assembly are connected to the outside of the stator core to form the fourth oil distribution path, which is used to discharge cooling oil from the stator core; the oil inlets of part of the core assembly are connected to the oil outlets of the remaining sections of the core assembly to form the fifth oil distribution path, which is used to directly spray cooling oil to the opposite winding end.

[0011] Furthermore, the stator core has oil inlet holes on both axial end faces. The two oil inlet holes on one end face are the first set of oil inlet holes, and the two oil inlet holes on the other end face are the second set of oil inlet holes. The first set of oil inlet holes and the second set of oil inlet holes are offset by an angle in the circumferential direction projected along the stator axis. The offset angle is equal to the first angle, and the offset direction is either clockwise or counterclockwise.

[0012] Furthermore, each of the two axial end faces of the stator core is provided with a symmetrically arranged group of oil inlets. Each group of oil inlets consists of two oil inlets. The two groups of oil inlets are located on the upper end face and the lower end face of the stator core, respectively, in the axial direction. When the drive motor assembly is installed vertically in the vehicle, the oil inlet group on the upper end face is located above the electric drive, and the line connecting the centers of the two oil inlets is parallel to the horizontal plane. The oil inlet group on the lower end face is located below the electric drive.

[0013] Furthermore, a housing is provided on the outside of the stator core, and a receiving cavity is formed inside the housing. The stator core is located in the receiving cavity and is coaxially arranged with the housing. An oil collecting ring is provided on the outer periphery of the stator core. The oil collecting ring is a thin-walled cylindrical structure and is arranged protruding from the end of the stator core.

[0014] According to another aspect of the present invention, a vehicle is provided having an oil-cooled stator, which is the oil-cooled stator described above.

[0015] By applying the technical solution of this invention, a continuous spiral cooling oil channel running through the entire stator core is constructed by axially stacking multiple core assemblies and rotating each segment by a specific angle. Each core assembly is composed of multiple laminations stacked together, with symmetrically distributed oil inlets and numerous oil outlets on the laminations. Interlayer connectivity of the oil channels is achieved between adjacent segments through axial misalignment and overlap of the oil inlets and outlets. This ensures that the cooling oil does not flow along a straight short-circuit path within the stator, but rather penetrates layer by layer and flows in multiple directions along a spiral path, sequentially flushing the core teeth, yoke, and winding gaps. This structure significantly shortens the heat transfer path from the copper wires and insulation layer to the cooling medium, overcoming the bottlenecks of high thermal resistance and uneven cooling in traditional water-cooled or unidirectional oil-sprayed structures. The multi-channel distribution of the spiral oil channels ensures that the oil uniformly covers the entire axial length of the stator, eliminating local hot spots and improving heat dissipation efficiency and temperature field consistency. Attached Figure Description

[0016] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0017] Figure 1 A schematic diagram of the assembly of the stator core, housing, and oil collecting ring according to the present invention is shown;

[0018] Figure 2 A schematic diagram of a structure of an embodiment of the core assembly according to the present invention is shown;

[0019] Figure 3 A schematic diagram of the structure of an embodiment of the lamination according to the present invention is shown;

[0020] Figure 4 A front view of an embodiment of the core assembly according to the present invention is shown;

[0021] Figure 5 A schematic diagram showing the flow direction of cooling oil between the layers of the core assembly according to the present invention is shown.

[0022] The above figures include the following reference numerals:

[0023] 11. Shell;

[0024] 12. Oil collecting ring;

[0025] 13. Stator core;

[0026] 21. Iron core assembly; 210. Laminations;

[0027] 31. Oil inlet hole;

[0028] 32. Oil outlet. Detailed Implementation

[0029] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0030] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0031] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0032] Exemplary embodiments according to this application will now be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. It should be understood that these embodiments are provided so that the disclosure of this application is thorough and complete, and that the concept of these exemplary embodiments is fully conveyed to those skilled in the art. In the drawings, for clarity, the thickness of layers and regions may be exaggerated, and the same reference numerals are used to denote the same devices, and therefore their description will be omitted.

[0033] With the rapid popularization of new energy electric vehicles, drive motors, as core power components, are continuously evolving towards higher torque and power densities. While performance indicators are constantly improving, motor temperature rise is becoming increasingly prominent, becoming a key bottleneck restricting its reliability and safety. Excessive temperature rise not only affects motor efficiency but may also cause insulation aging, magnet demagnetization, and other faults, directly threatening the stability and safety of the entire vehicle. Therefore, a scientifically sound and reasonable cooling structure design is of paramount practical importance in the development of drive motors.

[0034] Currently, motor cooling methods are mainly divided into two categories: air cooling and liquid cooling. Air cooling relies on airflow for heat exchange through the heat sink fins in the casing, and is divided into natural cooling and forced air cooling. However, its heat dissipation capacity is limited and it is difficult to meet the heat dissipation requirements of high power density motors. Liquid cooling has become the mainstream technology due to its high efficiency. Water cooling achieves heat exchange through water channels built into the casing. Although it is widely used, its cooling path is relatively long—the heat from the windings must be transferred through multiple layers such as copper wire, insulation layer, iron core, and casing before it can be carried away. This results in problems such as high thermal resistance, slow response, and low cooling efficiency.

[0035] In contrast, cooling oil possesses excellent insulation and chemical stability, is non-conductive and non-magnetic, and can directly contact the internal windings and core of the motor, achieving close-range or even direct cooling of the heat source. This significantly shortens the heat transfer path and improves heat dissipation efficiency. Especially with the widespread application of flat-wire motors, oil cooling technology can more effectively penetrate into the gaps between dense windings, achieving a more uniform temperature field distribution.

[0036] Oil cooling is mainly divided into two types: immersion oil cooling and spray oil cooling. Immersion oil cooling involves completely submerging the stator and rotor in oil, resulting in uniform cooling, but the oil agitation causes significant losses, affecting motor efficiency. Spray oil cooling, on the other hand, uses oil channels in the stator yoke to precisely spray cooling oil onto the end windings or heat-generating areas, achieving both cooling effect and efficiency optimization. However, traditional spray oil cooling structures still have significant shortcomings: short oil transmission paths, uneven oil distribution, and slow flow rates lead to poor cooling of the flat copper wires and iron core within the slots, making it difficult to fully realize the potential of oil cooling.

[0037] Combination Figures 1 to 5 As shown, according to a specific embodiment of this application, an oil-cooled stator is provided.

[0038] Specifically, such as Figure 2 , Figure 3 , Figure 4 As shown, the oil-cooled stator includes: a stator core 13, which is formed by stacking multiple core assemblies 21 along the axial direction; the core assembly 21 is formed by stacking multiple laminations 210, each lamination 210 having at least two oil inlets 31 and multiple oil outlets 32 along the circumferential direction, the oil inlets 31 on two adjacent core assemblies 21 partially overlapping, and a portion of the oil inlets 31 communicating with multiple oil outlets 32; two adjacent core assemblies 21 rotate along the stator axis by a first angle to form a spiral axial misalignment structure, and multiple spiral axial misalignment structures are connected to form a cooling oil channel, which is used to allow the cooling oil to flow continuously along a spiral path inside the stator core 13.

[0039] In one specific embodiment, the core structure of the oil-cooled stator is a stator core 13 composed of 23 core segments 21 axially stacked. The core is cylindrical with a total axial height of 48.3 mm, an outer diameter of 185 mm, and an inner diameter of 110 mm. It is nested outside the flat wire windings and coaxially assembled with the rotor in the electric drive system. Each core segment 21 is formed by stacking 72 cold-rolled non-oriented silicon steel sheets (laminated) with a thickness of 0.35 mm, with a stacking factor of 0.97. After stacking, it undergoes high-temperature curing to ensure a firm adhesion of the interlayer insulating coating, guaranteeing stable electromagnetic performance and eliminating the risk of short circuits.

[0040] When two adjacent core assemblies 21 are stacked axially, they are not simply aligned by translation. Instead, the latter segment is rotated counterclockwise (or clockwise) relative to the former segment around the stator axis by a first angle before being stacked. In this embodiment, 23 segments are used, which is sufficient to form a continuous, dense, and uninterrupted spiral oil passage. Since the lamination structure of each core assembly is exactly the same, after rotation, several oil outlets of the former segment and oil inlet holes of the latter segment form a partially overlapping area on the axial projection. This overlapping area constitutes a channel for oil to flow from the previous segment to the next stage, and the flow cross-sectional area of ​​this channel changes dynamically with the rotation angle, thereby achieving a natural distribution of oil flow rate in each segment along the axial direction.

[0041] Once all 23 core sections are stacked, the 46 oil inlets and 23 sets of oil outlets connect in the axial space to form a continuous spiral cooling oil channel. This oil channel is not a single channel, but rather consists of multiple parallel spiral paths connected in parallel.

[0042] Specifically, taking the first stack of stator core assemblies as a reference, the structure of the second stack of stator core assemblies is completely consistent with that of the first stack. At this time, the second stack of stator core assemblies is equivalent to the thickness of the first stack of stator core assemblies moved axially, so that the bottom surface of the second stack of stator core assemblies matches the top surface of the first stack. Then, the second stack of stator core assemblies is rotated around the axis of the stator core assembly by a first angle, and the position of the second stack of stator core assemblies is determined. The method for the third stack is the same as that for the second stack. The third stack of stator core assemblies is equivalent to the thickness of the second stack of stator core assemblies moved axially, so that the bottom surface of the third stack of stator core assemblies matches the top surface of the second stack. Then, the third stack of stator core assemblies is rotated around the axis of the stator core assembly in the same direction as the second stack by a first angle, and the position of the third stack of stator core assemblies is determined. The assembly method for the fourth to twenty-third stacks is the same as that for the second and third stacks, finally obtaining a complete stator core 13.

[0043] By applying the technical solution of this invention, a continuous spiral cooling oil channel running through the entire stator core is constructed by axially stacking multiple core assemblies and rotating each segment by a specific angle. Each core assembly is composed of multiple laminations stacked together, with symmetrically distributed oil inlets and numerous oil outlets on the laminations. Interlayer connectivity of the oil channels is achieved between adjacent segments through axial misalignment and overlap of the oil inlets and outlets. This ensures that the cooling oil does not flow along a straight short-circuit path within the stator, but rather penetrates layer by layer and flows in multiple directions along a spiral path, sequentially flushing the core teeth, yoke, and winding gaps. This structure significantly shortens the heat transfer path from the copper wires and insulation layer to the cooling medium, overcoming the bottlenecks of high thermal resistance and uneven cooling in traditional water-cooled or unidirectional oil-sprayed structures. The multi-channel distribution of the spiral oil channels ensures that the oil uniformly covers the entire axial length of the stator, eliminating local hot spots and improving heat dissipation efficiency and temperature field consistency.

[0044] Furthermore, each core assembly 21 is provided with two oil inlets 31 and multiple oil outlets 32 along the circumferential direction. The two oil inlets 31 are arranged symmetrically along the radial direction of the stator core 13, and the multiple oil outlets 32 are evenly distributed on both sides of the two oil inlets 31. The oil outlets 32 on both sides are arranged symmetrically with reference to the center line connecting the two oil inlets 31.

[0045] Each lamination has 86 oil outlet holes 32 and 2 oil inlet holes 31 evenly distributed around its outer circumference. All holes are stamped perpendicular to the lamination plane, with a 0.3mm chamfer on the inner edge of the hole opening to reduce oil flow disturbance. The two oil inlet holes 31 are arranged symmetrically in diameter, with the line connecting their centers passing through the geometric center of the stator core at an angle of 180°, forming elliptical through holes. The 86 oil outlet holes are 1.8mm in diameter and are circular holes. They are also centrally symmetrical about the axis of the two oil inlet holes, meaning each oil inlet hole is directly opposite 43 oil outlet holes, forming a clear symmetrical surface for fluid distribution.

[0046] Furthermore, the included angle between the two ends of each oil inlet hole 31 on the same stamping 210 is a second angle β, and the included angle between the center lines of two adjacent oil outlet holes 32 is a third angle γ, where 11°≤β≤12° and 3.5°≤γ≤4°.

[0047] Specifically, on the same lamination 210, the centers of the two oil inlets 31 are located on the same circumference of the stator core, and the line connecting their centers is perpendicular to the stator axis, forming a baseline in the diameter direction. The central angle between the two ends of the oil inlet 31 and the center is defined as the second angle β. Through simulation verification and experimental calibration, the value of β is in the range of 11° ≤ β ≤ 12°, with an optimal value of 11.25°. The angle between the two ends of the oil inlet 31 can be adjusted according to different coolant flow requirements to adapt to product requirements with different parameters.

[0048] Furthermore, the first angle ranges from 7° to 8°, and twice the third angle γ equals the first angle.

[0049] Preferably, in this embodiment, the first angle is 7.5°.

[0050] Eighty-six oil outlet holes 32 are evenly distributed circumferentially on both sides of the two oil inlet holes 31, forming two symmetrical groups, each group with 43 holes. The central angle between the centers of two adjacent oil outlet holes 32 on the circumference is defined as the third angle γ. After multiple rounds of CFD flow field simulation and thermo-fluid coupling simulation, the value of γ is limited to 3.5°≤γ≤4.0°, with a preferred value of 3.75°. The selection of this angle is not arbitrary, but based on the following triple engineering constraints:

[0051] Flow density constraint: If γ < 3.5°, the oil outlet density is too high and the wall thickness between holes is less than 0.5 mm. It is easy to deform and crack during stamping, and the oil passages between layers are easy to be connected due to burrs after stacking, resulting in oil pressure leakage or short circuit.

[0052] Spray coverage constraint: If γ>4.0°, the oil outlet hole spacing is too large, and the oil spray forms "point cooling" rather than "area coverage" at the winding end, resulting in local overheating of the copper wire gap and a temperature difference exceeding 25°C.

[0053] Spiral path matching constraint: γ=3.75° forms an integer multiple relationship of 2:1 with the first angle between adjacent iron core components. That is, every 7.5° rotation crosses the center distance of the two oil outlet holes by 3.75°×2. This allows the oil to naturally "align" with the center area of ​​the next set of oil outlet holes when flowing between layers, achieving the optimal connectivity efficiency of the oil circuit between layers and avoiding oil circuit interruption or sudden increase in flow resistance due to excessive misalignment.

[0054] This angular configuration allows the 86 oil outlets on the entire lamination to form a precise, stable, and non-redundant spray array on the circumference. After the 23 core assemblies are axially stacked and rotated 7.5° segment by segment, the oil outlets on each lamination form a spiral, uniformly dense, and equally spaced spray trajectory in three-dimensional space. Since γ=3.75°, for every 7.5° rotation, the oil spray point is precisely offset by 2 holes in the circumferential direction. Therefore, the oil flow sprayed from each core assembly forms a continuous, gapless annular spray band at the winding end, achieving a cooling coverage rate of over 99.2%.

[0055] Furthermore, the oil inlet holes 31 of each segment of the core assembly 21 located in the intermediate region form a first oil distribution path, a second oil distribution path, and a third oil distribution path for collecting cooling oil; the overlapping area of ​​a portion of the oil inlet hole 31 of the current segment of the core assembly 21 and the oil inlet hole 31 of the next segment of the core assembly 21 forms the first oil distribution path, which is used to conduct cooling oil to the next segment of the core assembly 21; a portion of the oil inlet hole 31 of the current segment of the core assembly 21 is connected to the oil outlet hole 32 of the next segment of the core assembly 21 to form the second oil distribution path, which is used to directly spray cooling oil to the opposite winding end; a portion of the oil inlet hole 31 of the current segment of the core assembly 21 is connected to the oil outlet hole 32 of the previous segment of the core assembly 21 to form the third oil distribution path, which is used to return cooling oil to the oil outlet hole 32 of the core assembly 21 of the previous layer.

[0056] like Figure 5 As shown, in the oil-cooled stator of the present invention, the 2nd to 22nd segments of the core assembly 21 located in the axial middle region—that is, the 21 intermediate segments not at the ends—each of their oil inlet holes 31 forms three independent, spatially separated, and functionally complementary cooling oil distribution channels in the axial direction with the structures of the adjacent upper and lower segments of the core assembly 21. These are defined as: the first oil distribution path, the second oil distribution path, and the third oil distribution path. These three paths are not achieved through independent pipes or valve bodies, but are naturally generated by the geometric overlap relationship formed after lamination.

[0057] First oil distribution path: Axial transmission path

[0058] The first oil distribution path is formed by the overlapping area of ​​an oil inlet hole 31 of the current core assembly 21 and an oil inlet hole 31 of the next core assembly 21 in the axial projection. Since the two adjacent core assemblies rotate counterclockwise by 7.5° along the axis, and each oil inlet hole 31 has a diameter of 5.2 mm, when the two sections are stacked, the center of the oil inlet hole of the next section is offset by 7.5° relative to the current section. This results in a crescent-shaped connecting area formed in the axial direction at the edges of the two oil inlets, with a minimum width of 0.6 mm and a maximum projected area of ​​approximately 28% (about 5.9 mm²) of the cross-sectional area of ​​a single oil inlet hole. This area is the only channel for oil to flow from the current section to the next stage. This path carries approximately 35% of the total cooling oil flow, acting as the main axial flow transport. After the cooling oil is injected from the upper oil inlet housing 11, it first enters the oil inlet hole of the first section, and then passes through this overlapping area, proceeding downwards section by section to ensure that the oil continuously and stably reaches the very end of the stator's axial direction. Because this path is achieved solely through geometric connectivity between the inlet ports, without any throttling structures, the flow resistance is extremely low, and the oil pressure decreases by less than 0.03 MPa along the entire axial path, ensuring the oil supply capacity of the bottom section. The continuity of this path depends on the consistency of the rotation angle of all intermediate sections. If any section is not rotated by 7.5°, it will cause a partial truncation of the path. Therefore, this embodiment requires that the overall axial concentricity of the 23 stacked sections be better than 0.05 mm to ensure that the overlapping area remains connected.

[0059] Second oil separation path: Direct spray path

[0060] The second oil distribution path is formed by the direct connection area between the edge of the oil inlet hole 31 of the current section of the core assembly 21 and the oil outlet hole 32 of the next section of the core assembly 21 on the axial projection. Since the 86 oil outlet holes 32 of the next section are evenly distributed at a 3.75° interval, and the center of the oil inlet hole 31 is exactly located in the middle of the two oil outlet holes (3.75°×2=7.5°), after the outer edge of the oil inlet hole of the current section is rotated, the two points on its circumference coincide with the inner edge of the two adjacent oil outlet holes of the next section, forming two symmetrical "fan-shaped openings", and the effective flow area of ​​each opening is about 1.2mm².

[0061] When the cooling oil flows through the current inlet, approximately 40% of the oil volume does not enter the next inlet, but is directly ejected at high speed through these two fan-shaped openings. The ejection direction is an angle of approximately 15°, combining axial and radial directions, determined by the lamination thickness and rotation angle. The ejection speed reaches 1.8 m / s, and the oil flow is atomized in a fan shape, precisely penetrating the gaps between the flat copper wires at the winding ends, directly impacting the copper wire surface, insulating varnish layer, and solder joint area. This path achieves "zero-distance cooling"—the cooling oil does not exchange heat through the iron core body, but is directly sprayed from the inlet to the heat source. The heat transfer path is shortened from the traditional structure of "copper wire → insulation → iron core → housing → oil" to "copper wire → oil," increasing heat exchange efficiency by more than 3 times.

[0062] The spray coverage of this path covers 68% of the circumferential area of ​​the winding end. Since each intermediate section forms two spray channels, the 21 intermediate sections form a total of 42 independent spray bands. When superimposed, they achieve 360° coverage of the winding end without dead angles, completely eliminating the "cooling blind zone" caused by mechanical assembly errors in traditional oil injection rings.

[0063] Third oil separation path: Reverse reflux path

[0064] The third oil distribution path is formed by the connecting area on the axial projection of the edge of the oil inlet 31 of the current section of the core assembly 21 and the oil outlet 32 ​​of the previous section of the core assembly 21. After cooling, some oil from the oil outlet of the previous section falls back to the outer edge of the core due to gravity and centrifugal force, forming a thin oil film. After the current section's oil inlet rotates, its lower 180° edge area overlaps with the outlet of the previously sprayed oil outlet, forming a reverse return channel. This channel allows approximately 25% of the cooling oil, after entering the current section's oil inlet, not to be conducted downwards or sprayed onto the opposite winding, but to flow back to the previous section and be sprayed out again through the previous section's oil outlet. The physical essence of this path is to utilize the residual heat of the returning oil for secondary use. Although the returning oil has absorbed some heat and its temperature has increased by about 5-8°C, it is still far below the 180°C heat resistance limit of the insulation material when it is sprayed out of the previous section. Its re-spraying can effectively reduce the local temperature rise peak in the oil inlet area.

[0065] The core engineering value of this approach lies in suppressing "inlet hot spots." In traditional oil cooling systems, the uppermost oil inlet area has the lowest oil temperature and the strongest heat exchange; a sudden temperature drop can easily lead to localized condensation or oil pressure fluctuations, resulting in bubble formation. This approach, however, actively recovers the refluxed oil, stabilizing the oil temperature in the inlet area at 45-50°C, preventing localized overcooling and oil vaporization, and improving system stability.

[0066] When the motor is running, cooling oil is injected from the two symmetrical oil inlets of the oil inlet housing 11 and simultaneously enters the two oil inlets 31 at the upper end of the stator core 13. 35% of the oil is conducted downwards segment by segment through the first oil distribution path as the main oil supply flow to ensure oil supply at the end of the system; 40% of the oil is directly sprayed to the end of the opposite winding through the second oil distribution path to achieve direct cooling of the core heat source; 25% of the oil flows back to the previous segment through the third oil distribution path to achieve local heat redistribution and temperature balance.

[0067] The three paths are spatially independent: the first path is the axial channel, located in the central area of ​​the oil inlet; the second path is the radial injection channel, located in the overlapping area between the outer edge of the oil inlet and the lower oil outlet; and the third path is the reverse return channel, located in the overlapping area between the lower edge of the oil inlet and the upper oil outlet. These three paths are concentrically distributed on the stamping plane, occupying the inner, outer, and transition zones respectively, without intersecting or interfering with each other.

[0068] In one specific embodiment, when the cooling oil enters the stator core 13 from the oil inlet hole of the first stack stator core assembly 21, the oil inlet hole 31 is directly opposite the two oil outlet holes 32 of the second stack stator core assembly 21 and the overlapping oil inlet hole 31. At this time, part of the cooling oil can enter the oil outlet hole 32 on the other side through the oil outlet holes 32 of the second to twenty-third stacks, and the cooling oil exchanges heat with the stator core 13, taking away the heat therein; the other part of the coolant passes through the oil inlet hole 31 of the second stack. At this time, the cooling oil entering the second stack oil inlet 31 has three paths: the third stack oil inlet 31, the third stack oil outlet 32, and the first stack oil outlet 32. The cooling oil will then enter the other side oil outlet 32 ​​through the oil outlet 32 ​​of the third to twenty-third stacks. The cooling oil exchanges heat with the stator core 13 and carries away the heat. The cooling oil entering from the first stack oil outlet 32 ​​will also carry away the heat and exit from the oil outlet 32 ​​on the oil inlet side, carrying away the heat from the corresponding position in the first stack. The third part of the oil will enter the third stack oil inlet 31. At this point, the cooling oil entering the third stack also has three pathways: the oil inlet 31 of the fourth stack, the oil outlet 32 ​​of the fourth stack, and the oil outlet 32 ​​of the second stack. The cooling oil will then pass through the oil outlet 32 ​​of the fourth to twenty-third stacks and enter the oil outlet 32 ​​on the other side, exchanging heat with the stator core 13 and carrying away the heat. The cooling oil entering from the oil outlet 32 ​​of the first stack also carries away heat, exiting from the oil outlet 32 ​​on the inlet side, carrying away the heat from the corresponding location in the first stack. A portion of the oil will enter the oil inlet 31 of the fourth stack. The oil flow path from the fourth to the twenty-second stack is the same as that of the second and third stacks.

[0069] In another specific embodiment, when cooling oil enters the stator core 13 from the oil inlet of the first stack stator core assembly 21, cooling oil is also injected into the oil inlet 31 of the twenty-third stack. The oil inlet 31 of the twenty-third stack is composed of two oil outlets 32 of the twenty-second stack stator core assembly 21 and an overlapping oil inlet 31. At this time, part of the cooling oil can enter the oil outlet 32 ​​on the other side through the oil outlet 32 ​​of the twenty-second stack to the first stack, and the cooling oil exchanges heat with the stator core 13, taking away the heat; the other part of the coolant passes through the oil inlet 31 of the twenty-second stack. At this time, the cooling oil entering the oil inlet 31 of the 22nd stack has three paths: the oil inlet 31 of the 21st stack, the oil outlet 32 ​​of the 21st stack, and the oil outlet 32 ​​of the 23rd stack. The cooling oil will pass through the oil outlet 32 ​​of the 21st stack to the oil outlet 32 ​​of the first stack and enter the oil outlet 32 ​​on the other side. The cooling oil exchanges heat with the stator core 13 and carries away the heat. The cooling oil entering from the oil outlet 32 ​​of the 23rd stack will also carry away the heat and exit from the oil outlet 32 ​​on the oil inlet side, carrying away the heat at the corresponding position of the 23rd stack. The third part of the oil will enter the oil inlet 31 of the 21st stack. At this point, the cooling oil entering the 21st stack also has three pathways: the oil inlet 31 of the 20th stack, the oil outlet 32 ​​of the 20th stack, and the oil outlet 32 ​​of the 22nd stack. The cooling oil will pass through the oil outlet 32 ​​from the 20th stack to the first stack and enter the oil outlet 32 ​​on the other side, exchanging heat with the stator core 13 and carrying away the heat. Similarly, the cooling oil entering from the oil outlet 32 ​​of the 23rd stack will also carry away heat, exiting from the oil outlet 32 ​​on the inlet side, carrying away the heat from the corresponding location in the 23rd stack. A portion of the oil will enter the oil inlet 31 of the 20th stack. The oil flow path from the 20th stack to the second stack is the same as that between the 22nd and 21st stacks.

[0070] Furthermore, the oil inlet holes 31 of the core assembly 21 at both ends form a fourth oil distribution path and a fifth oil distribution path for collecting cooling oil; the oil inlet holes 31 of the core assembly 21 are connected to the outside of the stator core 13 to form a fourth oil distribution path, which is used to discharge cooling oil from the stator core 13; a portion of the oil inlet holes 31 of the core assembly 21 are connected to the oil outlet holes 32 of the remaining sections of the core assembly 21 to form a fifth oil distribution path, which is used to directly spray cooling oil to the opposite winding end.

[0071] In the oil-cooled stator of the present invention, the structure and function of the oil inlet holes 31 of the first core assembly at the uppermost end of the axial direction and the twenty-third core assembly at the lowermost end—that is, the two ends of the stator core 13—are different from those of the middle section. They respectively form the fourth oil distribution path and the fifth oil distribution path, which work together with the three-path system of the middle 21 sections to form a three-dimensional oil cooling network with full axial direction, double-end inlet, multi-stage injection, and closed-loop reflux.

[0072] Fourth oil distribution path: End oil discharge channel

[0073] The fourth oil distribution path is formed by the area where the oil inlet hole 31 of the bottom twenty-third segment core assembly 21 is directly connected to the annular oil collecting ring 12 on the outer side of the stator core 13. The oil inlet hole 31 is still a circular through hole with a diameter of 5.2 mm in structure, but in the axial position, its lower end face is tightly fitted with the upper edge of the oil collecting ring 12 with a fitting gap of ≤0.1 mm. Moreover, the inner wall of the oil inlet hole 31 is partially enlarged into an annular groove in the 1 / 4 circumference area near the outer edge. The groove depth is 0.8 mm and the width is 1.5 mm, forming an "annular guide lip".

[0074] After the cooling oil has undergone sufficient heat exchange through the first 22 spiral paths, its temperature rises by approximately 14°C, eventually reaching the 23rd stage. At this point, the oil no longer flows downwards (because there is no lower stage) nor does it form a backflow (because there is no corresponding oil outlet in the upper stage). Instead, it directly overflows from the outer edge of the oil inlet 31 through this enlarged hole structure and enters the inner cavity of the annular oil collecting ring 12. This path is the fourth oil distribution path, which serves as the final oil discharge channel, handling approximately 15% of the total cooling oil flow.

[0075] This path eliminates the structural complexity and sealing risks associated with the traditional oil-cooling structure that requires a separate oil drain port at the end. At the same time, it utilizes the existing structure of the oil inlet hole to achieve oil drainage, thus achieving zero structural additions and self-functional conversion.

[0076] Fifth oil distribution path: End direct spray channel

[0077] The fifth oil distribution path is formed by the connected areas on the axial projection of the oil inlet holes 31 of the uppermost first section of the core assembly 21 and the oil outlet holes 32 of the remaining sections 2 to 22 of the core assembly 21. Since the first section is the initial injection point of the oil, its oil inlet holes 31 have not yet received any backflow or downward oil flow, so its internal oil pressure is at most about 0.4 MPa. On the circumference of the outer edge of the oil inlet hole in this section, there are two symmetrical fan-shaped areas located on both sides of the oil inlet hole on the axial projection, which are exactly aligned with the inlet ends of several oil outlet holes 32 in sections 2 to 22.

[0078] The fifth oil distribution path serves as an advanced spray and pre-cooling system for hot spots. Because traditional oil cooling systems experience lag in cooling the middle region during motor startup or high load, the oil flows downwards. This path, through "cross-section spraying," pre-cools the hottest areas with high-pressure impact cooling before the cooling oil absorbs heat from the middle sections, significantly reducing peak temperature rise.

[0079] In one specific embodiment, the oil entering the 23rd stack has two paths: it exits the stator core 13 from the oil inlet 31 of the 23rd stack, and it exits from the oil outlet 32 ​​of the oil outlet side of the oil outlet assembly from the 22nd stack core assembly to the first stack core assembly.

[0080] In another specific embodiment, the oil entering the first stack has two paths: it exits the stator core 13 from the oil inlet 31 of the first stack, and enters the oil outlet 32 ​​of the oil inlet side from the oil outlet 32 ​​of the oil outlet 32 ​​of the second stack core assembly to the twenty-third stack core assembly.

[0081] Furthermore, the stator core 13 has oil inlet holes 31 on both axial end faces. The two oil inlet holes 31 on one end face are the first set of oil inlet holes, and the two oil inlet holes 31 on the other end face are the second set of oil inlet holes. The first set of oil inlet holes and the second set of oil inlet holes have an offset angle in the circumferential direction projected along the stator axis. The offset angle is equal to the first angle, and the offset direction is either clockwise or counterclockwise.

[0082] The centers of the first and second sets of oil inlets are not aligned on the circumferential plane projected along the stator axis. Instead, they are offset by a precise circumferential angle. This offset angle is strictly equal to the "first angle" of rotation between the core components mentioned above—7.5°. The offset direction is either clockwise or counterclockwise, preferably counterclockwise.

[0083] Specifically, on the vertical projection plane of the stator axis, there is a relative rotation angle of 7.5° between the center line connecting the first set of oil inlets (i.e., their diameter line) and the center line connecting the second set of oil inlets. For example, if the center line connecting the first set of oil inlets is located at 0° and 180°, then the center line connecting the second set of oil inlets is located at 7.5° and 187.5° (counterclockwise offset); or at -7.5° and 172.5° (clockwise offset), and both directions must be consistent.

[0084] In a traditional dual-inlet oil structure, if the oil inlets at both ends are perfectly aligned (i.e., their projections coincide), the oil is injected simultaneously at both ends of the stator axis, forming a symmetrical dual-inlet pressure field. However, when the cooling oil flows downward along the spiral path, due to the oil's viscosity, frictional losses, and thermal expansion, the oil pressure at the lower end will inevitably be lower than that at the upper end, resulting in an axial pressure gradient in the system. This invention breaks the traditional symmetry by offsetting the oil inlets at both ends by 7.5°, introducing a controllable asymmetrical pressure input to achieve adaptive pressure compensation: the first set of oil inlets at the upper end (0°–180°) injects high-pressure oil, pushing the oil downward along the spiral path; the oil injected into the second set of oil inlets at the lower end (7.5°–187.5°) has its inlet position offset precisely from the upper oil flow's dominant area, avoiding "double-headed collision"; this offset places the lower oil inlet inlet in the "downstream offset area" of the upper oil flow, forming a natural "drainage-pressure compensation" effect.

[0085] Furthermore, each of the two symmetrically arranged oil inlet groups is provided on both axial end faces of the stator core 13. Each oil inlet group consists of two oil inlets, which are located on the upper and lower end faces of the stator core 13 respectively in the axial direction. When the drive motor assembly is vertically installed in the vehicle, the oil inlet group on the upper end face is located above the electric drive, and the line connecting the centers of its two oil inlets is parallel to the horizontal plane. The oil inlet group on the lower end face is located below the electric drive. The two oil inlets 31 of the stator core 13 must ensure that the flow rate remains consistent.

[0086] When the drive motor assembly is installed in the chassis of a new energy vehicle, its axis is arranged vertically, meaning the motor shaft is perpendicular to the ground. At this time, the axis of the stator core 13 is also vertical. The upper oil inlet group is located on the upper surface of the first core assembly 21 at the top of the stator core 13. The line connecting the centers of its two oil inlets 31 is strictly parallel to the horizontal plane, i.e., arranged along the left-right lateral direction of the vehicle, and its height is at the highest point of the electric drive assembly. The lower oil inlet group is located on the lower surface of the twenty-third core assembly 21 at the bottom of the stator core 13. The line connecting the centers of its two oil inlets 31 is also parallel to the horizontal plane, and its height is at the lowest point of the electric drive assembly. When the motor stops, the cooling oil naturally settles downwards due to gravity. The upper oil inlet group, located at the highest point, serves as an air collection and venting port, automatically expelling air or vapor bubbles accumulated at the top before system restart. The lower oil inlet group, located at the lowest point, acts as the main oil inlet, ensuring that the oil pump preferentially draws in liquid oil upon startup, avoiding cavitation and flow fluctuations caused by idling and air intake. Micro-bubbles inevitably generate in the oil circuit system during operation. Because the upper oil inlet group is located at the highest point with its openings facing upwards, the bubbles naturally gather and escape upwards under buoyancy, eliminating the need for an additional venting valve. This structure achieves an integrated "oil inlet, venting outlet" design, greatly simplifying system accessories and reducing the risk of failure. The upper oil inlet group serves as the oil injection point, located in the "high potential energy zone," where the oil flows naturally downwards with the assistance of gravity, reducing the oil pump load. The lower oil inlet group serves as the auxiliary pressure replenishment port, located in the "low potential energy zone," used to compensate for the pressure drop caused by friction along the spiral path, forming a two-stage oil supply mode of "high-level injection + low-level pressure replenishment," which reduces the total system pressure drop by 40% and reduces the oil pump power by more than 15%.

[0087] Optionally, the oil discharged from the lower oil inlet group falls directly into the inner cavity of the oil collecting ring 12 without turning or bending, reducing backflow resistance and ensuring stable secondary spray flow.

[0088] The design has three core components, further elaborated as follows: Figure 1As shown, a housing 11 is provided on the outside of the stator core 13, and a receiving cavity is formed inside the housing 11. The stator core 13 is located in the receiving cavity and is coaxially arranged with the housing 11. An oil collecting ring 12 is provided on the outer periphery of the stator core 13. The oil collecting ring 12 is a thin-walled cylindrical structure and is arranged protruding from the end of the stator core 13.

[0089] The stator core is equipped with matching housings 11 and annular oil collecting rings 12 at both ends. The oil inlet housing is a one-piece aluminum alloy structure with two symmetrical annular pressure equalizing oil chambers on the inner wall. The diameter of the chambers is precisely matched with the two end faces of the stator core. The outer wall of the housing has two external oil inlet holes, located at the top and bottom of the housing, respectively, which connect to the oil pipes of the vehicle's cooling system. When the oil pump starts, the cooling oil enters the pressure equalizing chamber of the upper oil inlet housing through the top oil inlet hole. After the oil is quickly pressure equalized in the chamber, it is injected into the upper end face of the stator core from the two oil inlet holes. Since the upper oil inlet hole and the lower oil outlet hole are strictly symmetrically arranged at 180° in axial projection and are located at the highest and lowest points when the electric drive assembly is installed vertically, the cooling oil slowly permeates from top to bottom under the combined action of gravity assistance and spiral oil channels, flows through all 23 core components, and finally sprays out from the lower oil outlet hole into the annular oil collecting ring 12.

[0090] The oil collecting ring 12 is a thin-walled cylindrical structure made of 316L stainless steel with a wall thickness of 0.8mm. Its outer diameter is the same as that of the stator core 13, 185mm, and its inner diameter is 183.5mm, forming a 1.5mm gap with the outer surface of the stator core. The oil collecting ring 12 protrudes axially from both ends of the stator core 13, with an axial height of 15mm, extending upwards and downwards by 7.5mm from the end of the stator core, forming an "end-expanding annular oil collecting groove".

[0091] After the cooling oil is sprayed out from the oil outlets 32 of each section of the stator core 13, the oil droplets splash downwards or upwards along the outer circumference of the stator core due to gravity and centrifugal force. The protruding structure of the oil collecting ring 12 forms an annular oil collection pool, and the 1.5mm gap between its inner wall and the surface of the stator core forms a "capillary drainage channel", so that all the sprayed oil is captured within 10ms, with no leakage and no splashing.

[0092] The oil collecting ring 12 forms an annular oil collecting cavity, where all the oil flowing out of the stator core instantly converges, equalizes pressure, and stabilizes flow. Multiple oil injection holes are evenly distributed along the circumference of the inner wall of the oil collecting ring. Each injection hole has a diameter of 2.5 mm, and its axis is inclined at a 15° angle to the stator axis, all pointing towards the gap between the copper wires at the winding ends. Because the oil collecting ring has a thin-walled structure, its internal cavity volume is small and its response is fast, ensuring that the oil injection pressure remains stable at 0.2~0.3 MPa, matching the main oil circuit pressure and avoiding weak injection or overpressure.

[0093] Optionally, the sub-core 13 is configured to be axially stacked from 23 core assemblies 21, each segment having a thickness of λ (mm). The total axial length of the 23 segments is then L = 23λ. Each core assembly 21 has multiple oil outlet holes 32, and their total flow cross-sectional area is denoted as A. i (i=1~23), the "effective cooling path length" of the oil sprayed from each oil outlet along the axial direction is denoted as L. i (That is, the average oil flow propagation distance from the oil outlet to the winding heat source, which is affected by the injection angle, centrifugal force, and winding structure). This invention sets that for any i-th segment (i∈[1,23]), its A... i ×L i =22λ, meaning that the "comprehensive oil injection capacity" of each independent segment is equal to the total thickness of the remaining 22 segments. This relationship implies that the cooling oil injection capacity per unit axial length is completely consistent; each segment has the same capacity to remove heat load from the winding ends; therefore, although the oil is injected from the top and flows downwards segment by segment, the axial temperature gradient is forcibly suppressed to an extremely low level because the "oil injection efficiency" of each segment is equivalently compensated. Since the cooling oil enters from the oil inlets 31 at both ends, there is only an initial flow injection state of "no front-segment backflow and no rear-segment diversion" at the inlets (the first and twenty-third segments). Therefore, the instantaneous flow rate at these two oil inlets 31 is the maximum of the system, far exceeding the oil outlet flow rate of the middle segment.

[0094] Optionally, the thickness of each core assembly 21 can be set differently.

[0095] If some of the oil outlets 32 in a section of the core assembly become blocked by impurities, the cooling oil can still continue to flow through the remaining 85 oil outlets 32 and the interlayer staggered oil passages. Because the oil passages have a multi-channel parallel structure, and the total length and cross-sectional area of ​​each cooling path are consistent, blockages will not interrupt the oil flow path; only a slight local temperature rise will occur, preventing a chain reaction of thermal runaway. The system can identify local hot spots through temperature sensor feedback, but without requiring shutdown, it can still maintain operation at over 85% of its rated continuous power.

[0096] According to another aspect of the present invention, a vehicle is provided having an oil-cooled stator, which is the oil-cooled stator described above.

[0097] The oil-cooled stator of the drive motor requires no manual intervention during operation. Cooling oil is continuously supplied by an external oil pump and automatically distributed to the oil inlets 31 at both ends of the stator through the housing 11. Under all operating conditions of the motor (start-up, rated operation, overload, regenerative braking), the cooling oil continuously performs a four-step cooling process: "spiral staggered interlayer progression—multi-path diversion—axial spraying—end re-spraying," achieving full coverage, low thermal resistance, and high-response cooling of the winding copper wires, core teeth, yoke, and ends. The system structure requires no moving parts and consumes no additional drive energy, relying solely on oil pressure and geometric configuration to achieve efficient self-organized cooling, making it suitable for the harsh operating environment of new energy vehicles with high speed, high torque, and frequent start-stop cycles.

[0098] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0099] In addition to the above, it should be noted that the terms "one embodiment," "another embodiment," and "embodiment" used in this specification refer to specific features, structures, or characteristics described in connection with that embodiment, which are included in at least one embodiment described in the general description of this application. The appearance of the same expression in multiple places in the specification does not necessarily refer to the same embodiment. Furthermore, when a specific feature, structure, or characteristic is described in connection with any embodiment, the intention is to suggest that implementing such a feature, structure, or characteristic in conjunction with other embodiments also falls within the scope of this invention.

[0100] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0101] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An oil-cooled stator, characterized in that, include: The stator core (13) is formed by stacking multiple core assemblies (21) along the axial direction; The core assembly (21) is formed by stacking multiple laminations (210). Each lamination (210) is provided with at least two oil inlet holes (31) and multiple oil outlet holes (32) along the circumferential direction. The oil inlet holes (31) on two adjacent sections of the core assembly (21) are partially overlapped. A portion of the oil inlet hole (31) is connected to the multiple oil outlet holes (32). Two adjacent core assemblies (21) rotate a first angle along the stator axis to form a spiral axial misalignment structure. Multiple spiral axial misalignment structures are connected to form a cooling oil channel, which is used to allow cooling oil to flow continuously along a spiral path inside the stator core (13).

2. The oil-cooled stator according to claim 1, characterized in that, Each of the core assemblies (21) is provided with two oil inlets (31) and multiple oil outlets (32) along the circumferential direction. The two oil inlets (31) are arranged symmetrically along the radial direction of the stator core (13), and the multiple oil outlets (32) are evenly distributed on both sides of the two oil inlets (31). The oil outlets (32) on both sides are arranged symmetrically with respect to the center line connecting the two oil inlets (31).

3. The oil-cooled stator according to claim 2, characterized in that, The included angle between the two ends of each oil inlet hole (31) on the same lamination (210) is a second angle β, and the included angle between the center lines of two adjacent oil outlet holes (32) is a third angle γ, where 11°≤β≤12° and 3.5°≤γ≤4°.

4. The oil-cooled stator according to claim 3, characterized in that, The first angle ranges from 7° to 8°, and twice the third angle γ is equal to the first angle.

5. The oil-cooled stator according to claim 2, characterized in that, The oil inlet (31) of each section of the core assembly (21) located in the middle region forms a first oil distribution path, a second oil distribution path and a third oil distribution path for collecting cooling oil; The overlapping area of ​​the oil inlet (31) of the current segment of the core assembly (21) and the oil inlet (31) of the next segment of the core assembly (21) forms the first oil distribution path, which is used to conduct cooling oil to the next segment of the core assembly (21). The oil inlet (31) of the current segment of the core assembly (21) is connected to the oil outlet (32) of the next segment of the core assembly (21) to form the second oil distribution path, which is used to directly spray the cooling oil to the opposite winding end. The oil inlet (31) of the current segment of the core assembly (21) is connected to the oil outlet (32) of the previous segment of the core assembly (21) to form the third oil distribution path. The third oil distribution path is used to return the cooling oil to the oil outlet (32) of the core assembly (21) of the previous layer.

6. The oil-cooled stator according to claim 2, characterized in that, The oil inlet (31) of the core assembly (21) located at both ends forms a fourth oil distribution path and a fifth oil distribution path for collecting cooling oil; The oil inlet (31) of the core assembly (21) is connected to the outside of the stator core (13) to form a fourth oil distribution path, which is used to discharge cooling oil from the stator core (13). The oil inlet (31) of a portion of the core assembly (21) is connected to the oil outlet (32) of the remaining sections of the core assembly (21) to form the fifth oil distribution path, which is used to directly spray the cooling oil to the opposite winding end.

7. The oil-cooled stator according to claim 1, characterized in that, The stator core (13) has oil inlet holes (31) on both axial end faces. The two oil inlet holes (31) on one end face are the first set of oil inlet holes, and the two oil inlet holes (31) on the other end face are the second set of oil inlet holes. The first set of oil inlet holes and the second set of oil inlet holes are offset by an angle in the circumferential direction projected along the stator axis. The offset angle is equal to the first angle, and the offset direction is either clockwise or counterclockwise.

8. The oil-cooled stator according to claim 7, characterized in that, Each of the two axial end faces of the stator core is provided with a symmetrically arranged group of oil inlets. Each group of oil inlets consists of two oil inlets. The two groups of oil inlets are located on the upper end face and the lower end face of the stator core (13) respectively in the axial direction. When the drive motor assembly is installed vertically in the vehicle, the oil inlet group on the upper end face is located above the electric drive, and the line connecting the centers of the two oil inlets is parallel to the horizontal plane. The oil inlet group on the lower end face is located below the electric drive.

9. The oil-cooled stator according to claim 6, characterized in that, A housing (11) is provided on the outside of the stator core (13), and a receiving cavity is formed inside the housing (11). The stator core (13) is located in the receiving cavity, and the stator core (13) and the housing (11) are coaxially arranged. The stator core (13) is provided with an oil collecting ring (12) on its outer periphery. The oil collecting ring (12) is a thin-walled cylindrical structure and is provided at the end of the stator core (13).

10. A vehicle, characterized in that, The vehicle has an oil-cooled stator, which is the oil-cooled stator according to any one of claims 1-9.

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