Compact and light oil-cooled flat wire hub motor

Abstract

A kind of compact and light oil cooling flat wire hub motor, comprising: main oil circuit cooling system, with main oil channel being arranged on machine base, rear oil injection ring being arranged between rear end cover and stator winding, front oil injection ring being arranged between front end cover and stator winding;Oil circuit cooling system, with oil channel being arranged on machine base, end cover oil channel being arranged on rear end cover;Oil recovery system, with oil return channel being arranged at the bottom of machine base, oil outlet being arranged at the rear end of oil return channel.The scheme can reuse the cooperation of each component in limited space to form the components of main oil circuit cooling system, oil circuit cooling system, oil recovery system, and in addition, the stator assembly adopts flat wire winding, which uses its high slot fill rate characteristics to improve power density and performance, so that the overall innovation makes the overall structure of the hub motor more compact and lighter.

Description

Technical Field

[0001] This invention relates to the field of motor structure technology, and in particular to a compact and lightweight oil-cooled flat wire wheel-side motor. Background Technology

[0002] In recent years, with increasing environmental awareness and policy support, oil-cooled motors have been widely used in the field of new energy vehicles. Oil-cooled motors ensure the reliability of the stator and rotor by adjusting the cooling method of the stator and rotor, and improve the output power and power density of the motor.

[0003] A Chinese patent (patent number: ZL202320081211.7) discloses a motor with an oil-cooled structure. This patent's technical solution uses a front rotor pressure plate and a rear rotor pressure plate to allow the cooling oil in the oil-cooling cavity to be thrown to the stator assembly above the motor housing cavity. Simultaneously, a large amount of oil mist is formed within the stator housing cavity, thereby cooling the stator assembly above the motor housing cavity and also cooling and lubricating the front and rear bearings. While this patent provides a solution with minimal internal structural modifications and low cost, the cooling effect on the winding ends and bearings is not precise, and the motor is also bulky and heavy.

[0004] Furthermore, in using the motor as a wheel-side motor, the applicant discovered that the existing technology could not meet the stringent adjustment requirements of the unique installation position of the wheel-side motor. As a power source located close to the wheel, the development of the wheel-side motor faces stringent challenges due to its unique installation position, as follows:

[0005] 1. First of all, the wheel side is one of the most congested areas of the entire vehicle. It must share limited space with key components such as brake discs, suspension, and steering tie rods. This requires the wheel side motor to have a highly compact structure and lightweight characteristics, with extreme space constraints and lightweight requirements.

[0006] 2. Secondly, since the wheel-side motor is located in a confined space, and the motor is prone to accumulating heat when operating at high power in a narrow space, it leads to decreased efficiency, forced power limitation, and even irreversible demagnetization failure of the permanent magnet. At the same time, high temperature will accelerate the aging of surrounding bearing seals, wiring harnesses and other components, significantly reducing the overall reliability of the system, thus posing a severe heat dissipation challenge.

[0007] 3. Furthermore, the bearings of wheel-side motors (especially the inner rotor hub type) need to withstand huge dynamic loads such as vehicle weight, driving torque, and road impact, and are exposed to harsh environments such as water, mud, and sand for a long time. They also face the challenge of meeting complex bearing loads and extreme environmental conditions.

[0008] In view of this, how to solve the problems that existing oil-cooled motors cannot meet as wheel-side motors, such as the constraints of mechanism space and the need for lightweighting, heat dissipation adjustment, complex bearing load and environmental extreme adjustment, has become the research topic to be solved by this invention. Summary of the Invention

[0009] The present invention provides a compact and lightweight oil-cooled flat wire wheel-side motor, the purpose of which is to solve at least one of the problems faced by existing oil-cooled motors as wheel-side motors, such as space constraints and lightweight requirements, heat dissipation adjustment, complex bearing load and environmental extreme adjustment.

[0010] To achieve the above objectives, the present invention provides a compact and lightweight oil-cooled flat wire wheel-side motor. The wheel-side motor has a frame, a front cover, a rear cover, a stator assembly, and a rotor assembly. The stator assembly includes a stator body and stator windings. The rotor assembly includes a stator body, a rotor body, a shaft, and motor bearings. A bearing chamber is provided on the rear cover. The wheel-side motor includes a main oil cooling system, a branch oil cooling system, and an oil recovery system.

[0011] The main oil cooling system has a main oil passage on the frame, a rear oil spray ring between the rear end cover and the stator winding, and a front oil spray ring between the front end cover and the stator winding. The main oil passage and the rear oil spray ring are connected by a through hole a, and are sealed by the frame, the end of the stator body and the rear oil spray ring to form an oil groove c; and are sealed by the frame, the end of the stator body and the front oil spray ring to form an oil groove d. The stator body has an axial slot connecting the oil grooves c and d. The oil grooves c and d are circumferentially arranged with spray holes facing the end of the stator winding.

[0012] The oil distribution cooling system has an oil distribution channel on the base and an end cover oil channel on the rear cover. The base and the rear oil spray ring seal form an oil groove f to connect the oil distribution channel and the main oil channel. The oil distribution channel, the end cover oil channel, and the bearing chamber are connected in sequence.

[0013] The oil recovery system has an oil return channel located at the bottom of the machine base and an oil outlet located at the rear end of the oil return channel. The oil outlet is connected to an external oil pump and an oil storage container, and the oil storage container is connected to the main oil channel.

[0014] The wheel-side motor is configured such that: the stator winding adopts a flat wire winding; the base and the front and rear covers cooperate to form a cavity, and an immersion chamber connected to the return oil channel is set at the bottom of the cavity. The oil in the immersion chamber and / or the oil storage container is pumped into the main oil circuit cooling system by an external oil pump. Part of the oil in the main oil circuit cooling system is evenly sprayed circumferentially towards the end of the stator winding through the spray holes of oil tank c and oil tank d and then falls into the immersion chamber. Part of the oil in the main oil circuit cooling system enters the branch oil circuit cooling system. The oil in the branch oil circuit cooling system enters the bearing chamber through oil tank f and then falls into the immersion chamber.

[0015] The design principle and technical concept of this invention are as follows: This invention studies the structure of a wheel-side motor that uses oil cooling. Existing oil-cooled motors cannot meet the space constraints, lightweight requirements, heat dissipation adjustments, complex bearing loads, and extreme environmental conditions faced by wheel-side motors. Therefore, this invention designs a compact and lightweight oil-cooled flat-wire wheel-side motor. To meet the aforementioned special conditions and requirements, the oil cooling system is designed as a multi-path synergistic oil cooling system comprising a main oil cooling system, a branch oil cooling system, and an oil recovery system. In this multi-path synergistic oil cooling system, the main oil cooling system's oil spray / injection directly washes the winding end surface, achieving efficient and directional cooling and effectively removing end heat. The system reduces hotspot temperatures, prevents permanent magnet demagnetization and insulation aging, and enhances continuous power capability. It achieves precise end-spray cooling, direct core cooling, and shell / immersion cooling. The distributed oil cooling system directly cools and lubricates the bearings, addressing the unique high-temperature challenges faced by wheel-side motor bearings (brake heat, motor heat conduction, ambient high temperatures). This effectively controls bearing temperature, provides additional lubrication and cleaning, delays aging, and significantly improves bearing reliability and lifespan. The oil recovery system works closely with the main oil cooling system and the distributed oil cooling system to achieve closed-loop oil recovery and supply. Furthermore, the windings near the bottom cavity are immersed in the cooling system, where the oil viscosity provides damping and vibration absorption, absorbing some of the mid-to-high frequency vibration energy. Better temperature control prevents gap changes caused by thermal deformation and reduces abnormal noise. In addition to achieving functional integration and complementarity between the wheel-side motors, the above multi-path collaborative oil cooling system also shares a large number of components such as the frame, front cover, rear cover, stator assembly, rotor assembly, rear injection ring, and front injection ring in its main oil circuit cooling system, branch oil circuit cooling system, and oil recovery system. This component sharing allows for the reuse of various components within a limited space to form the main oil circuit cooling system, branch oil circuit cooling system, and oil recovery system. Furthermore, the stator assembly uses flat wire windings, leveraging their high slot fill factor to improve power density and performance. This overall innovation makes the wheel-side motor more compact and lighter. Ultimately, the axial length of the wheel-side motor can be shortened by 10-15% compared to the mainstream wheel-side motor (320-350mm), and the weight can be reduced by 15-25%. It effectively overcomes the core challenges of wheel-side motors in terms of space constraints, severe overheating risks, and harsh environments with high bearing loads. It ensures the thermal stability of the motor and the reliability of the system within a very limited space. In particular, it provides efficient solutions for key bottlenecks such as hot spots at the winding ends and high bearing temperatures. The damping and vibration absorption effect of the oil in the immersion chamber further improves NVH performance.

[0016] The relevant content of this invention is explained as follows:

[0017] 1. In the description of this application, it should be understood that the terms “center”, “length”, “horizontal”, “front”, “rear”, “upper”, “lower”, “axial”, “radial”, “circumferential”, etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0018] 2. In the description of this application, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly defined. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0019] 3. In the description of this application, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0020] 4. In the above technical solution of the present invention, in the oil distribution cooling system, a through hole e connecting the main oil passage and the rear oil injection ring is correspondingly provided on the base, and an oil groove f connecting to the through hole e is formed by the base and the rear oil injection ring. The base is provided with a through hole g connecting the oil groove f and the oil distribution passage. This design allows the oil distribution passage and the main oil passage to be better connected, allowing the oil in the main oil passage to enter the oil distribution passage better. At the same time, the design of the oil groove f connecting to the through hole e formed by the base and the rear oil injection ring allows the formation of the oil distribution cooling system to share the rear oil injection ring, base and other structures with the main oil distribution cooling system, making the structure of the motor more compact and allowing for a lighter design.

[0021] 5. In the above technical solution of the present invention, the rear injection ring and the front injection ring are ring structures arranged opposite to each other. The ring structure includes an inner ring and an outer ring that are connected and extend toward the end of the stator body. The extension length of the inner ring is greater than that of the outer ring. An opening groove is formed between the inner ring and the outer ring, which opens toward the end of the stator body. A seal is formed between the inner ring and the end of the stator body, and a seal is formed between the outer ring and the inner wall of the base. The gap between the outer ring and the base and the end of the stator body, as well as the space where the opening groove is located, form oil grooves c and d. With this ring structure design, it can be assembled at the front and rear ends of the stator assembly to form the rear injection ring and the front injection ring, and together with the base and the end of the stator body, respectively form oil grooves c and d. The structure is ingeniously designed and provides a reliable, stable and sealed oil groove structure.

[0022] 6. In the above technical solution of the present invention, the inner ring body is circumferentially distributed with radial circular holes that extend to the opening slot. These radial circular holes constitute injection holes on the oil grooves c and d facing the stator winding end, so that the oil pumped by the main oil passage into the oil grooves c and d can be accurately sprayed to the stator winding end through the injection holes. This ring structure design within the motor's internal space, with its radially inward structural extension design, only occupies the radial space inside the motor and does not occupy the axial space of the motor, thereby allowing the axial length of the motor to be further reduced.

[0023] 7. In the above technical solution of the present invention, two sealing rings are provided between the outer ring body of the rear injection ring and the inner wall of the base. One sealing ring is located between the through hole a and the through hole e, and the other sealing ring is located at the rear end of the through hole e. This ensures that when the rear injection ring is used to form the main oil circuit cooling system and the branch oil circuit cooling system, the common part (groove) formed by the rear injection ring and other components can have a good seal, ensuring the normal operation of the main oil circuit cooling system and the branch oil circuit cooling system, and further ensuring the thermal stability of the motor and the reliability of the system within the limit space.

[0024] 8. In the above technical solution of the present invention, between the two sealing rings provided between the outer ring body and the inner wall of the base, an oil groove f connected to the through hole e is formed by the base and the rear oil injection ring. This design makes the formation of the oil groove f more reasonable in structure, and the sealing performance of the part shared with the base and the rear oil injection ring is good, further ensuring the normal and stable operation of the oil distribution cooling system.

[0025] 9. In the above technical solution of the present invention, a cooling oil observation hole is provided on the rear end cover corresponding to the oil passage of the end cover, so that when the wheel-side motor is maintained, the maintenance personnel can more clearly and explicitly know the oil condition in the oil circuit cooling system used for bearing cooling, and it can also be used to infer the oil condition of the multi-path coordinated oil cooling system, thereby reducing the difficulty of maintenance.

[0026] 10. In the above technical solution of the present invention, the rear end cover is provided with an oil inlet on its upper part, which is connected to an external oil storage container. The oil inlet is matched with the main oil passage on the machine base. The rear end cover is provided with an oil inlet hole that connects the end cover oil passage and the branch oil passage. The oil inlet hole is matched with the branch oil passage. This design allows the rear end cover to be better matched with the machine base, making the structure between the main oil passage in the main oil cooling system, the branch oil passage in the branch oil cooling system and the end cover oil passage more compact. Under the premise of stable operation, the axial length of the machine base is shortened, thereby further reducing the axial length of the motor.

[0027] 11 In the above technical solution of the present invention, the base is provided with at least one through hole i connecting the soaking chamber and the return oil channel. The through hole i is directly below the end of the stator winding. The oil is quickly recycled and circulated through the through hole i. After the oil in the oil tank c and oil tank d is sprayed to the end of the stator winding through the spray hole, it can be directly pumped and recycled by an external oil pump through the through hole i and the return oil channel, thereby improving the recycling efficiency and the oil spraying / injection efficiency, and thus improving the cooling effect.

[0028] 12. In the above technical solution of the present invention, the oil circuit cooling system further includes a transmission cooling branch, wherein the transmission cooling branch includes a branch interface h disposed on the base and connected to the main oil passage, wherein the branch interface h is connected to an external oil pipe to provide an auxiliary cooling oil source for the external transmission, thereby providing good oil cooling for the transmission used in conjunction with the wheel-side motor, ensuring that the equipment equipped with the wheel-side motor of the present invention shares a set of oil cooling oil supply, and reducing the overall wheel-side space occupied by the equipment.

[0029] Due to the application of the above-mentioned solution, the present invention has the following advantages and effects compared with the prior art:

[0030] 1. The above-mentioned solution of the present invention, through research on the structure of wheel-side motors using oil cooling, addresses the limitations of existing oil-cooled motors in meeting the constraints of mechanism space, lightweight requirements, heat dissipation adjustment, complex bearing loads, and extreme environmental conditions faced by wheel-side motors. Therefore, the present invention designs a compact and lightweight oil-cooled flat wire wheel-side motor. To meet the aforementioned special conditions and requirements, the oil cooling system is designed as a multi-path synergistic oil cooling system comprising a main oil cooling system, a branch oil cooling system, and an oil recovery system. In this multi-path synergistic oil cooling system, the main oil cooling system's oil spray / injection directly washes the winding end surface, achieving efficient and directional cooling, effectively removing end heat, and reducing heat loss. Temperature control prevents permanent magnet demagnetization and insulation aging, enhancing continuous power capability. This is achieved through precise spraying at the winding ends, direct core cooling, and shell / immersion cooling. The distributed oil cooling system directly cools and lubricates the bearings, addressing the unique high-temperature challenges faced by wheel-side motor bearings (brake heat, motor heat conduction, ambient high temperatures). This effectively controls bearing temperature, provides additional lubrication and cleaning, delays aging, and significantly improves bearing reliability and lifespan, fulfilling the bearing cooling and lubrication function. Furthermore, the oil recovery system works closely with the main oil cooling system and the distributed oil cooling system to achieve closed-loop oil recovery and supply. Immersion cooling is implemented near the bottom cavity windings, where the oil viscosity provides damping and vibration absorption, absorbing some mid-to-high frequency vibration energy. Improved temperature control avoids gap changes caused by thermal deformation, reducing abnormal noise.

[0031] 2. In the above-described solution of the present invention, the multi-path coordinated oil cooling system, in addition to achieving functional integration and complementarity of the wheel-side motors, structurally, shares a large number of components such as the frame, front end cover, rear end cover, stator assembly, rotor assembly, rear injection ring, and front injection ring in the main oil circuit cooling system, the branch oil circuit cooling system, and the oil recovery system. Through component sharing, the cooperation of various components can be reused within a limited space to form the main oil circuit cooling system, the branch oil circuit cooling system, and the oil recovery system. Furthermore, the stator assembly uses flat wire windings, utilizing their high slot fill factor characteristics to improve power density. The overall innovation in terms of degree and performance makes the wheel-side motor more compact and lighter. Ultimately, the axial length of the wheel-side motor can be shortened by 10-15% compared to the mainstream wheel-side motor (320-350mm), and the weight can be reduced by 15-25%. It effectively overcomes the core problems of wheel-side motors in terms of space constraints, severe overheating risks, and harsh environments with high bearing loads. It ensures the thermal stability of the motor and the reliability of the system in a very limited space. In particular, it provides efficient solutions for key bottlenecks such as hot spots at the winding ends and high bearing temperatures. The damping and vibration absorption effect of the oil in the immersion chamber further improves NVH performance. Attached Figure Description

[0032] Appendix Figure 1This is a three-dimensional structural diagram of an embodiment of the present invention;

[0033] Appendix Figure 2 This is a cross-sectional schematic diagram of an embodiment of the present invention;

[0034] Appendix Figure 3 for Figure 2 Enlarged diagram of part A in the diagram;

[0035] Appendix Figure 4 This is a partial cross-sectional schematic diagram of an embodiment of the present invention;

[0036] Appendix Figure 5 This is a perspective view of the rear end cover in an embodiment of the present invention;

[0037] Appendix Figure 6 This is a schematic diagram of the rear fuel injection ring in an embodiment of the present invention;

[0038] Appendix Figure 7 This is a schematic diagram illustrating the connection between the wheel-side motor and other external structures in an embodiment of the present invention;

[0039] Appendix Figure 8 This is a schematic diagram of the oil flow direction according to an embodiment of the present invention (I);

[0040] Appendix Figure 9 This is a schematic diagram (II) of the oil flow direction in an embodiment of the present invention.

[0041] The parts shown in the above attached diagram are illustrated below:

[0042] 1. Base;

[0043] 10. Soaking chamber; 11. Main oil passage; 12. Branch oil passage; 13. Return oil passage;

[0044] 14. Through hole a; 15. Through hole e; 16. Through hole g; 17. Through hole i;

[0045] 2. Front cover;

[0046] 3. Rear end cover;

[0047] 30. Bearing housing; 31. End cover oil passage; 32. Cooling oil inspection hole; 33. Oil inlet; 34. Oil inlet hole;

[0048] 4. Stator assembly;

[0049] 41. Stator body; 411. Axial slot; 42. Stator winding;

[0050] 5. Rotor assembly;

[0051] 51. Rotor body; 52. Shaft; 53. Motor bearing;

[0052] 6. Ring structure;

[0053] 610. Rear fuel injection ring; 620. Front fuel injection ring;

[0054] 61. Inner ring; 62. Outer ring; 63. Opening groove; 64. Injection hole; 65. Sealing ring;

[0055] 71. Oil tank c; 72. Oil tank d; 73. Oil tank f;

[0056] 8. Oil outlet;

[0057] 9. Splitting interface h. Detailed Implementation

[0058] The present invention will be clearly described below with illustrations and detailed description. Any person skilled in the art who understands the embodiments of the present invention can make changes and modifications based on the technology taught in the present invention without departing from the spirit and scope of the present invention.

[0059] This invention aims to address the challenges posed by existing oil-cooled motors in meeting the spatial constraints, lightweight requirements, heat dissipation adjustments, complex bearing loads, and extreme environmental conditions faced by wheel-side motors. The invention innovatively designs a compact and lightweight oil-cooled flat wire wheel-side motor, specifically designed for high-power-density distributed drive scenarios.

[0060] As attached Figure 1 To be continued Figure 7 As shown in the figure, an embodiment of the present invention discloses a compact and lightweight oil-cooled flat wire wheel-side motor. The wheel-side motor has a base 1, a front end cover 2, a rear end cover 3, a stator assembly 4, and a rotor assembly 5. The stator assembly 4 includes a stator body 41 and a stator winding 42. The rotor assembly 5 includes a rotor body 51, a shaft 52, and a motor bearing 53. A bearing chamber 30 is provided on the rear end cover 3. The wheel-side motor includes a main oil circuit cooling system, a branch oil circuit cooling system, and an oil recovery system.

[0061] The main oil cooling system includes a main oil passage 11 on the base 1, a rear oil spray ring 610 between the rear end cover 3 and the stator winding 42, and a front oil spray ring 620 between the front end cover 2 and the stator winding 42. The main oil passage 11 and the rear oil spray ring 610 are connected by a through hole a14. An oil groove c71 is formed by sealing the base 1, the end of the stator body 41, and the rear oil spray ring 610. An oil groove d72 is formed by sealing the base 1, the end of the stator body 41, and the front oil spray ring 620. The stator body 41 is provided with an axial slot 411 connecting the oil groove c71 and the oil groove d72. The oil groove c71 and the oil groove d72 are circumferentially arranged with spray holes 64 facing the end of the stator winding 42.

[0062] The oil distribution cooling system has an oil distribution channel 12 on the base 1 and an end cover oil channel 31 on the rear cover 3. The base 1 and the rear oil spray ring 610 seal to form an oil groove f73 to connect the oil distribution channel 12 and the main oil channel 11. The oil distribution channel 12, the end cover oil channel 31 and the bearing chamber 30 are connected in sequence.

[0063] The oil recovery system has an oil return channel 13 located at the bottom of the base 1 and an oil outlet 8 located at the rear end of the oil return channel 13. The oil outlet 8 is connected to an external oil pump and an oil storage container, and the oil storage container is connected to the main oil channel 11.

[0064] The wheel-side motor is configured such that: the stator winding 42 adopts a flat wire winding; the base 1, the front cover 2, and the rear cover 3 cooperate to form a cavity, and an immersion chamber 10 connected to the return oil channel 13 is provided at the bottom of the cavity. The oil in the immersion chamber 10 and / or the oil storage container is pumped into the main oil circuit cooling system by an external oil pump. Part of the oil in the main oil circuit cooling system is evenly sprayed circumferentially towards the end of the stator winding 42 through the spray holes 64 of the oil tank c71 and the oil tank d72 and then falls into the immersion chamber 10. Part of the oil in the main oil circuit cooling system enters the branch oil circuit cooling system. The oil in the branch oil circuit cooling system enters the bearing chamber 30 through the oil tank f73 and then falls into the immersion chamber 10.

[0065] refer to Figure 8 , Figure 9 The given diagram illustrates the oil flow direction. The working process of this embodiment of the invention can be referenced as follows:

[0066] 1. When the motor is running and the external oil pump is working, the oil in the soaking chamber 10 and / or the oil storage container is pumped into the main oil passage 11 of the main oil circuit cooling system.

[0067] 2. Part of the oil in the main oil cooling system enters the oil groove c71 formed by the sealing of the machine base 1, the end of the stator body 41 and the rear oil spray ring 610 through the main oil passage 11 and through hole a14. Then it enters the oil groove d72 through the axial slot 411 of the stator body 41. Then it is sprayed / injected towards the end of the stator winding 42 through the spray holes 64 arranged circumferentially in the oil groove c71 and the oil groove d72.

[0068] 3. The oil in the main oil passage 11 of the main oil circuit cooling system enters the oil passage 12 of the oil distribution cooling system through the oil groove f73 formed by the sealing of the base 1 and the rear oil spray ring 610. The oil in the oil passage 12 enters the bearing chamber 30 through the end cover oil passage 31 to cool and lubricate the motor bearing 53 in the bearing chamber 30.

[0069] 4. The oil sprayed into the end of the stator winding 42 in the main oil circuit cooling system enters the soaking chamber 10 from the end of the stator winding 42. The oil in the bearing chamber 30 in the branch oil circuit cooling system flows into the soaking chamber 10 at the bottom under the suction of the oil pump and gravity. The oil flows out of the motor through the return oil channel 13 and the oil outlet 8 and enters the external oil storage container.

[0070] 5. An external oil pump pumps the oil in the oil storage container back to the main oil passage 11 of the main oil circuit cooling system, completing the closed-loop return flow.

[0071] Through the implementation of embodiments of the present invention, and through research on structures using oil cooling for wheel-side motors, it was found that existing oil-cooled motors cannot meet the problems faced by wheel-side motors, such as space constraints, lightweight requirements, heat dissipation adjustments, complex bearing loads, and extreme environmental adjustments. Therefore, the present invention designs a compact and lightweight oil-cooled flat-wire wheel-side motor. To meet the aforementioned special conditions and requirements, the oil cooling system is designed as a multi-path synergistic oil cooling system comprising a main oil cooling system, a branch oil cooling system, and an oil recovery system. In this multi-path synergistic oil cooling system, the main oil cooling system's oil spray / injection directly washes the winding end surface, achieving efficient and directional cooling, effectively removing end heat, and reducing heat loss. Temperature control prevents permanent magnet demagnetization and insulation aging, enhancing continuous power capability. This achieves precise cooling of the winding ends, direct core cooling, and shell / immersion cooling. The distributed oil cooling system directly cools and lubricates the bearings, addressing the unique high-temperature challenges faced by the wheel-side motor bearings (brake heat, motor heat conduction, ambient high temperature). It effectively controls bearing temperature, provides additional lubrication and cleaning, delays aging, and significantly improves bearing reliability and lifespan, fulfilling the bearing cooling and lubrication function. The oil recovery system works closely with the main oil cooling system and the distributed oil cooling system to achieve closed-loop oil recovery and supply. Furthermore, the windings near the bottom cavity are immersed in the cooling system, where the oil viscosity provides damping and vibration absorption, absorbing some of the mid-to-high frequency vibration energy. Improved temperature control avoids gap changes caused by thermal deformation, reducing abnormal noise.

[0072] In addition to integrating and complementing the functions of the wheel-side motors, the above multi-path collaborative oil cooling system also shares a large number of components such as the frame 1, front cover 2, rear cover 3, stator assembly 4, rotor assembly 5, rear oil injection ring 610, and front oil injection ring 620 in terms of structure. By sharing components, the main oil circuit cooling system, the branch oil circuit cooling system, and the oil recovery system can be formed by repeatedly utilizing the cooperation of various components in a limited space. In addition, the stator assembly 4 adopts flat wire winding, which utilizes its high slot fill factor to improve power density and performance. Thus, the overall innovation makes the wheel-side motor more compact and lighter in weight.

[0073] In embodiments of the present invention, such as Figure 2 and Figure 4 As shown, in the oil distribution cooling system, the base 1 is provided with a through hole e15 connecting the main oil passage 11 and the rear oil injection ring 610. The base 1 and the rear oil injection ring 610 seal together to form an oil groove f73 connecting to the through hole e15. The base 1 is provided with a through hole g16 connecting the oil groove f73 and the oil distribution passage 12. This design allows the oil distribution passage 12 and the main oil passage 11 to be better connected, allowing the oil in the main oil passage 11 to enter the oil distribution passage 12 better. At the same time, the design of the oil groove f73 formed by the base 1 and the rear oil injection ring 610 to connect to the through hole e15 allows the formation of the oil distribution cooling system to share the rear oil injection ring 610, the base 1, and other structures with the main oil distribution cooling system, making the structure of the motor more compact and allowing for a lighter design.

[0074] In embodiments of the present invention, such as Figure 6 and Figure 3 As shown, the rear injection ring 610 and the front injection ring 620 are ring structures 6 arranged opposite each other. The ring structure 6 includes an inner ring 61 and an outer ring 62 that are connected and extend toward the end of the stator body 41. The extension length of the inner ring 61 is greater than that of the outer ring 62. An opening groove 63 is formed between the inner ring 61 and the outer ring 62, opening toward the end of the stator body 41. The inner ring 61 and the end of the stator body 41 form a seal. The outer ring 62... A seal is formed between the outer ring body 62 and the inner wall of the base 1. The gap between the outer ring body 62 and the ends of the base 1 and the stator body 41, as well as the space where the opening slot 63 is located, form oil grooves c71 and d72. With this ring structure 6 design, it can be assembled at the front and rear ends of the stator assembly 4 to form the rear oil injection ring 610 and the front oil injection ring 620, and together with the ends of the base 1 and the stator body 41, they form oil grooves c71 and d72 respectively. The structure is ingeniously designed and provides a reliable, stable and sealed oil groove structure.

[0075] In embodiments of the present invention, such as Figure 6 and Figure 3 As shown, the inner ring 61 has radially distributed circular holes that extend to the opening slot 63. These radially distributed circular holes form the injection holes 64 on the oil sump c71 and oil sump d72 facing the end of the stator winding 42. This allows the oil pumped by the main oil passage 11 into the oil sump c71 and oil sump d72 to be accurately sprayed onto the end of the stator winding 42 through the injection holes 64. This design of the ring structure 6 within the motor's internal space, with its radially inward structural extension, only occupies the radial space inside the motor and does not occupy the axial space, thereby allowing the axial length of the motor to be further reduced.

[0076] In embodiments of the present invention, such as Figure 3As shown, two sealing rings 65 are provided between the outer ring body 62 of the rear injection ring 610 and the inner wall of the base 1. One sealing ring 65 is located between the through hole a14 and the through hole e15, and the other sealing ring 65 is located at the rear end of the through hole e15. This ensures that when the rear injection ring 610 is used to form the main oil circuit cooling system and the branch oil circuit cooling system, the common parts (grooves) formed by the rear injection ring 610 and other components can have a good seal, ensuring the normal operation of the main oil circuit cooling system and the branch oil circuit cooling system, and further ensuring the thermal stability of the motor and the reliability of the system within the limit space.

[0077] In embodiments of the present invention, such as Figure 3 As shown, between the two sealing rings 65 provided between the outer ring body 62 and the inner wall of the base 1, an oil groove f73 is formed by the base 1 and the rear oil injection ring 610, which connects to the through hole e15. This design makes the formation of the oil groove f73 more structurally reasonable, and the sealing performance of the part shared with the base 1 and the rear oil injection ring 610 is better, further ensuring the normal and stable operation of the oil distribution cooling system.

[0078] In embodiments of the present invention, such as Figure 4 and Figure 5 As shown, the rear end cover 3 is provided with a cooling oil observation hole 32 corresponding to the end cover oil passage 31, so that when the wheel-side motor is maintained, the maintenance personnel can more clearly and clearly know the oil condition in the oil circuit cooling system used for bearing cooling. It can also be used to infer the oil condition of the multi-path collaborative oil cooling system, thereby reducing the difficulty of maintenance.

[0079] In embodiments of the present invention, such as Figure 4 and Figure 5 As shown, the rear end cover 3 has an oil inlet 33 on its upper part that connects to an external oil storage container. The oil inlet 33 is matched with the main oil passage 11 on the base 1. The rear end cover 3 has an oil inlet hole 34 that connects the end cover oil passage 31 and the branch oil passage 12. The oil inlet hole 34 is matched with the branch oil passage 12. This design allows the rear end cover 3 to better match the base 1, making the structure between the main oil passage 11 in the main oil cooling system, the branch oil passage 12 in the branch oil cooling system and the end cover oil passage 31 more compact. Under the premise of stable operation, the axial length of the base 1 is shortened, thereby allowing the axial length of the motor to be further reduced.

[0080] In embodiments of the present invention, such as Figure 2As shown, the base 1 has at least one through hole i17 connecting the soaking chamber 10 and the oil return channel 13. The through hole i17 is directly below the end of the stator winding 42. The oil is quickly recycled and circulated through the through hole i17. After the oil in the oil tank c71 and oil tank d72 is sprayed onto the end of the stator winding 42 through the spray hole 64, it can be directly pumped back by an external oil pump through the through hole i17 and the oil return channel 13, thereby improving the recycling efficiency and the oil spraying / injection efficiency, and thus improving the cooling effect.

[0081] In embodiments of the present invention, such as Figure 2 and Figure 7 As shown, the oil cooling system also includes a transmission cooling branch. The transmission cooling branch includes a branch interface h9 installed on the base 1 and connected to the main oil passage 11. The branch interface h9 is connected to an external oil pipe to provide an auxiliary cooling oil source for the external transmission, thereby providing good oil cooling for the transmission used in conjunction with the wheel-side motor. This ensures that the equipment equipped with the wheel-side motor of the present invention shares a set of oil cooling supply, reducing the overall wheel-side space occupied by the equipment.

[0082] Through the implementation of the above embodiments, this invention effectively overcomes the core challenges of wheel-side motors in terms of space constraints, severe overheating risks, and harsh environments with high bearing loads by employing a compact and lightweight design with shorter axial length and lighter weight, as well as an innovative multi-path collaborative oil cooling system. The system integrates the main oil circuit (precise spraying at the winding ends + direct cooling of the core + shell / immersion cooling), branch oil circuits (bearing cooling and lubrication + optional transmission cooling), and closed-loop oil recovery, ensuring the thermal stability of the motor and the reliability of the system within a very limited space. In particular, it provides efficient solutions to key bottlenecks such as hot spots at the winding ends and high bearing temperatures. Thus, the objectives of this invention are achieved.

[0083] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A compact and lightweight oil-cooled flat wire wheel-side motor, the wheel-side motor having a frame, a front end cover, a rear end cover, a stator assembly, and a rotor assembly, the stator assembly including a stator body and stator windings, the rotor assembly including a rotor body, a shaft, and a motor bearing, and a bearing housing provided on the rear end cover, characterized in that, The wheel-side motor includes: The main oil cooling system includes a main oil passage on the frame, a rear oil spray ring between the rear end cover and the stator winding, and a front oil spray ring between the front end cover and the stator winding. The main oil passage and the rear oil spray ring are connected by a through hole a, and are sealed by the frame, the end of the stator body, and the rear oil spray ring to form an oil groove c. The frame, the end of the stator body, and the front oil spray ring are also sealed to form an oil groove d. The stator body has an axial slot connecting the oil grooves c and d. The oil grooves c and d are circumferentially arranged with spray holes facing the end of the stator winding. The oil distribution cooling system has an oil distribution channel on the base and an end cover oil channel on the rear cover. The base and the rear oil spray ring seal form an oil groove f to connect the oil distribution channel and the main oil channel. The oil distribution channel, the end cover oil channel, and the bearing chamber are connected in sequence. The oil recovery system has an oil return channel located at the bottom of the machine base and an oil outlet located at the rear end of the oil return channel. The oil outlet is connected to an external oil pump and an oil storage container, and the oil storage container is connected to the main oil channel. The wheel-side motor is configured such that: the stator winding adopts a flat wire winding; the base and the front and rear covers cooperate to form a cavity, and an immersion chamber connected to the return oil channel is set at the bottom of the cavity. The oil in the immersion chamber and / or the oil storage container is pumped into the main oil circuit cooling system by an external oil pump. Part of the oil in the main oil circuit cooling system is evenly sprayed circumferentially towards the end of the stator winding through the spray holes of oil tank c and oil tank d and then falls into the immersion chamber. Part of the oil in the main oil circuit cooling system enters the branch oil circuit cooling system. The oil in the branch oil circuit cooling system enters the bearing chamber through oil tank f and then falls into the immersion chamber.

2. The compact and lightweight oil-cooled flat wire wheel-side motor according to claim 1, characterized in that: In the oil distribution cooling system, a through hole e is provided on the base to connect the main oil passage and the rear oil injection ring. An oil groove f is formed by the base and the rear oil injection ring to connect to the through hole e. A through hole g is provided on the base to connect the oil groove f and the oil distribution passage.

3. A compact and lightweight oil-cooled flat wire wheel-side motor according to claim 2, characterized in that: The rear and front oil injection rings are ring structures arranged opposite each other. Each ring structure includes an inner ring and an outer ring that are connected and extend toward the end of the stator body. The extension length of the inner ring is greater than that of the outer ring. An opening groove is formed between the inner and outer rings and opens toward the end of the stator body. A seal is formed between the inner ring and the end of the stator body, and a seal is formed between the outer ring and the inner wall of the base. The gap between the outer ring and the base and the end of the stator body, as well as the space where the opening groove is located, form oil groove c and oil groove d.

4. A compact and lightweight oil-cooled flat wire wheel-side motor according to claim 3, characterized in that: The inner ring body has radial circular holes evenly distributed around the circumference, which extend to the opening slot. These radial circular holes constitute the injection holes on the oil grooves c and d facing the end of the stator winding.

5. A compact and lightweight oil-cooled flat wire wheel-side motor according to claim 3, characterized in that: Two sealing rings are provided between the outer ring body of the rear injection ring and the inner wall of the base, one of which is located between the through hole a and the through hole e, and the other is located at the rear end of the through hole e; a sealing ring is provided between the inner ring body facing the front end and the stator body.

6. A compact and lightweight oil-cooled flat wire wheel-side motor according to claim 5, characterized in that: Between the two sealing rings provided between the outer ring body and the inner wall of the base, an oil groove f is formed by the base and the rear oil injection ring, which connects to the through hole e.

7. A compact and lightweight oil-cooled flat wire wheel-side motor according to claim 1, characterized in that: A cooling oil observation hole is provided on the rear end cover corresponding to the oil passage of the end cover.

8. A compact and lightweight oil-cooled flat wire wheel-side motor according to claim 1, characterized in that: The rear end cover has an oil inlet on its upper part that connects to an external oil storage container, and the oil inlet is matched with the main oil passage on the machine base; the rear end cover has an oil inlet hole that connects the end cover oil passage and the branch oil passage, and the oil inlet hole is matched with the branch oil passage.

9. A compact and lightweight oil-cooled flat wire wheel-side motor according to claim 1, characterized in that: The base is provided with at least one through hole i that connects the soaking chamber and the oil return channel, and the through hole i is directly below the end of the stator winding.

10. A compact and lightweight oil-cooled flat wire wheel-side motor according to claim 1, characterized in that: The oil distribution cooling system also includes a transmission cooling branch, which includes a branch interface h installed on the engine block and connected to the main oil passage. The branch interface h is connected to an external oil pipe to provide an auxiliary cooling oil source for the external transmission.

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