Oil-cooled motor and oil path structure thereof

Abstract

The invention provides an oil-way structure of an oil-cooled motor, and the structure comprises a motor housing which is provided with an oil pool at the bottom; a stator oil path channel and a rotor oil path channel are integrated on the motor shell; the stator oil way channel penetrates through the motor shell and extends to a stator assembly area, and the rotor oil way channel penetrates through the motor shell and extends to a rotor assembly area. The oil cooler is arranged on the motor shell; an oil inlet of the oil pump assembly communicates with the oil pool, and an oil outlet of the oil pump assembly communicates with the inlet end of the oil cooler, so that high-temperature oil is conveyed into the oil cooler; the outlet end of the oil cooler is connected with the stator oil way channel and the rotor oil way channel so that cooling oil can be conveyed to the stator assembly area and the rotor assembly area and flow back to the oil pool, and oil cooling circulation is formed. A dispersed oil way structure is integrated on the shell, so that the structure is compact; the stator oil way channel and the rotor oil way channel ensure that cooling oil is accurately conveyed to a heating area and flows back to an oil pool to form circulation, and the effectiveness of heat exchange is improved.

Description

Technical Field

[0001] This application relates to the field of electric drive system technology for new energy vehicles, and in particular to an oil-cooled motor and its oil circuit structure. Background Technology

[0002] In the electric drive system of new energy vehicles, the continuous high-power operation of the drive motor generates a large amount of heat, and excessive temperature rise can seriously affect the motor's performance, lifespan, and operational reliability. For effective heat dissipation, air cooling, liquid cooling, and oil cooling are common motor cooling methods. As the requirements for power density, efficiency, and cost of drive motors in new energy vehicles continue to increase, traditional air cooling and liquid cooling methods are gradually becoming insufficient to meet the demands in terms of heat dissipation capacity or system complexity. Oil cooling technology, due to its excellent heat dissipation performance and the advantage of direct contact cooling, has become the mainstream cooling solution for high-power drive motors. However, existing high-power oil-cooled drive motors have the following drawbacks: (1) The system is bulky and not compact. To achieve oil cooling circulation, existing solutions usually require the configuration of independent oil pumps, oil coolers, filters, and complex external oil pipes or internal oil passages connecting these components. These independent components and complex pipeline connections significantly increase the overall size and space occupied by the motor system, which is not conducive to the miniaturization and lightweight design of the electric drive system; (2) The manufacturing cost is high. The cost of special components such as oil pumps, oil coolers, and filters is high. At the same time, the process of processing complex oil passages, arranging multiple oil pipes, and integrating these dispersed components also greatly increases the complexity and cost of manufacturing and assembly. (3) The oil circuit structure is complex and the oil circuit design is unreasonable, resulting in insufficient cooling of key heat-generating areas, affecting the reliability of heat dissipation, and thus affecting the stability of long-term motor operation. Summary of the Invention

[0003] This application provides an oil-cooled motor and its oil circuit structure to solve the technical problems in the related art, such as the large overall size, high manufacturing cost, and insufficient cooling efficiency of the drive motor due to the dispersed structure, numerous parts, and complex pipelines of the oil circuit cooling system.

[0004] In a first aspect, an oil circuit structure for an oil-cooled motor is provided, comprising: a motor housing with an oil sump at its bottom; a stator oil circuit channel and a rotor oil circuit channel integrated on the motor housing; the stator oil circuit channel penetrating the motor housing and extending to the stator assembly area, and the rotor oil circuit channel penetrating the motor housing and extending to the rotor assembly area; an oil cooler disposed on the motor housing; an oil pump assembly with its inlet connected to the oil sump and its outlet connected to the inlet end of the oil cooler for conveying high-temperature oil to the oil cooler; and the outlet end of the oil cooler connected to the stator oil circuit channel and the rotor oil circuit channel respectively for conveying cooling oil to the stator assembly area and the rotor assembly area respectively, and returning it to the oil sump to form an oil cooling cycle.

[0005] In some embodiments, the oil pump assembly includes a first oil pump and a second oil pump symmetrically arranged on both sides of the bottom of the oil tank; the oil inlets of the first oil pump and the second oil pump are both connected to the oil tank, and the oil outlets of the first oil pump and the second oil pump are connected to the inlet end of the oil cooler after being merged through parallel pipelines.

[0006] In some embodiments, an oil collecting ring is connected to the end of the stator oil passage, and the oil collecting ring is located at the end of the winding. The oil collecting ring has an annular cavity inside and multiple radial injection holes are opened on the oil collecting ring. The annular cavity is connected to the stator oil passage so as to spray cooling oil to the end of the winding through the radial injection holes.

[0007] In some embodiments, the radial injection holes are distributed circumferentially along the oil collecting ring, and a denser group of injection holes is provided in the ring segment corresponding to the high-temperature region at the end of the winding.

[0008] In some embodiments, an oil guide cover is also included, which is fixed to the rotor end face; a shaft oil passage is provided inside the rotor assembly; the rotor oil passage is connected to the shaft oil passage through the back flow channel of the oil guide cover, so as to allow the cooling oil to be thrown to the winding end when the rotor rotates at high speed.

[0009] In some embodiments, an oil guide cover is also included, which is fixed to the rotor end face; the rotor assembly is provided with a shaft oil passage; the surface of the oil guide cover facing the winding end is provided with an oil slinger groove, which is connected to the shaft oil passage; the oil slinger groove is a groove radiating outward from the shaft of the oil guide cover, and the groove depth gradually decreases from the inner diameter to the outer diameter.

[0010] In some embodiments, the oil cooler is installed on the top of the housing, and its outlet end is connected to the stator oil passage and the rotor oil passage respectively through a branched pipeline.

[0011] In some embodiments, the bottom of the oil sump is provided with an inclined guide surface, and the oil inlet of the oil pump assembly is located at the lowest point of the inclined guide surface; the side wall of the housing is provided with guide ribs to allow the cooling oil to flow back to the oil sump along the guide ribs.

[0012] In some embodiments, a temperature sensor assembly and a controller are also included; the temperature sensor assembly is located in the axial region of the stator assembly and the rotor assembly; the controller is signal-connected to the oil pump assembly and the temperature sensor assembly respectively, for adjusting the output power of the oil pump assembly according to the temperature signal.

[0013] Secondly, this application also proposes an oil-cooled motor, which utilizes the proposed oil circuit structure.

[0014] The beneficial effects of the technical solution provided in this application include: This application provides an oil circuit structure for an oil-cooled motor. The motor housing integrates stator and rotor oil circuit channels, consolidating what would otherwise be independently installed oil circuits into the motor housing. This eliminates the complex external oil pipes or dispersed internal oil channels of traditional solutions, reducing the space occupied by dispersed component placement. The oil cooler is directly mounted on the motor housing, and the oil pump assembly is connected to the oil sump and oil cooler via an integrated channel, avoiding the dispersed installation of independent components and making the overall structure more compact, effectively reducing the motor's overall size. Integrating the stator and rotor oil circuits into the motor housing reduces the use of additional pipes, connectors, and other auxiliary components. The stator oil circuit channels extend to the stator assembly area, and the rotor oil circuit channels extend to the rotor assembly area, ensuring precise delivery of cooling oil to the core heat-generating areas. After being cooled by the oil cooler, the cooling oil is split into two paths directly to the stator and rotor areas, then flows back to the oil sump to form a circulation, improving the timeliness and effectiveness of heat exchange. This solves the technical problems of large overall size, high manufacturing cost, and insufficient cooling efficiency in related technologies due to the dispersed structure, numerous components, and complex piping of the oil cooling system in drive motors. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the housing structure of the oil-cooled motor provided in an embodiment of this application; Figure 2 This is a schematic diagram of the overall structure of the oil-cooled motor provided in an embodiment of this application; Figure 3 This is a schematic diagram of the oil guide cover structure provided in an embodiment of this application; Figure 4 This is a schematic cross-sectional view of an oil-cooled motor provided in an embodiment of this application.

[0017] In the diagram: 1. Housing; 2. Oil sump; 3. Stator oil passage; 4. Rotor oil passage; 5. Oil pump assembly; 51. First oil pump; 52. Second oil pump; 6. Oil cooler; 7. Winding end; 8. Oil guide cover; 9. Branch pipeline. Detailed Implementation

[0018] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0019] To make the technical problem that this application aims to solve clearer, the causes of the technical problem will be analyzed in detail below.

[0020] To achieve cooling circulation, existing high-power oil-cooled drive motors require additional independent components such as oil pumps, oil coolers, and filters, with each component connected by complex external oil pipes or internal oil passages. The dispersed arrangement of these independent components directly increases the overall space occupied by the motor system, resulting in larger dimensions. The design of the external oil pipe routing and the complex bends in the internal oil passages, such as the circuitous paths designed to avoid other structures of the motor, further exacerbate the looseness of the structure, making it impossible to achieve an integrated layout, which conflicts with the miniaturization and lightweight requirements of electric drive systems for new energy vehicles. The additional specialized components such as oil pumps, oil coolers, and filters need to be purchased or customized separately, directly increasing hardware costs. Complex oil circuit structures, such as welding multiple oil pipe sections and precision boring and milling of internal oil passages, require higher machining accuracy and process complexity. Simultaneously, the assembly of dispersed components requires multiple positioning and sealing operations, increasing labor and time costs and leading to an overall increase in manufacturing costs. In existing technologies, the oil circuit is not optimized for core heat-generating areas of the motor, such as the winding ends, making it difficult for cooling oil to act precisely and efficiently on high-temperature areas, resulting in insufficient localized heat dissipation. Low circulation efficiency is also a concern; dispersed components and complex piping increase oil flow resistance, reducing the circulation speed of the cooling oil and affecting the timely removal of heat. Furthermore, sealing problems at pipe connections may lead to oil leakage, further weakening the cooling effect and affecting the long-term stability of the motor.

[0021] In summary, the core problem with existing technologies lies in the design flaws of component decentralization and oil circuit complexity, which makes them unable to meet the requirements of new energy vehicles for high-power oil-cooled motors in terms of space utilization, cost control, and cooling efficiency.

[0022] In a first aspect, embodiments of this application provide an oil circuit structure for an oil-cooled motor, referring to... Figures 1 to 4 , Figure 1 This is a schematic diagram of the housing structure of an oil-cooled motor provided in an embodiment of this application. Figure 1As shown, an oil circuit structure for an oil-cooled motor includes: a motor housing 1 with an oil sump 2 at its bottom; a stator oil circuit channel 3 and a rotor oil circuit channel 4 integrated on the motor housing 1; the stator oil circuit channel 3 penetrates the motor housing 1 and extends to the stator assembly area, and the rotor oil circuit channel 4 penetrates the motor housing 1 and extends to the rotor assembly area; an oil cooler 6 is disposed on the motor housing 1; an oil pump assembly 5 has an oil inlet connected to the oil sump 2 and an oil outlet connected to the inlet end of the oil cooler 6 for conveying high-temperature oil to the oil cooler 6; the outlet end of the oil cooler 6 is connected to the stator oil circuit channel 3 and the rotor oil circuit channel 4 respectively for conveying cooling oil to the stator assembly area and the rotor assembly area respectively, and returning to the oil sump 2 to form an oil cooling cycle.

[0023] By setting up this structure, the stator oil passage 3 and the rotor oil passage 4 are integrated on the motor housing 1, integrating the oil passage structure that might have been set up independently into the inside of the motor housing 1. This eliminates the complex external oil pipes or scattered internal oil passages in the traditional solution, reducing the space occupied by the dispersed arrangement of components. The oil cooler 6 is directly set on the motor housing 1, and the oil pump assembly 5 is connected to the oil sump 2 and the oil cooler 6 through an integrated channel, avoiding the dispersed installation of independent components, making the overall structure more compact and effectively reducing the size of the motor. By integrating the stator and rotor oil circuits through the motor housing 1, the use of additional pipes, connectors and other auxiliary components is reduced; the stator oil circuit channel 3 extends to the stator assembly area and the rotor oil circuit channel 4 extends to the rotor assembly area, ensuring that the cooling oil can be accurately delivered to the core heat-generating areas; after being cooled by the oil cooler 6, the cooling oil is divided into two paths to the stator and rotor areas, and then flows back to the oil sump 2 to form a cycle, which improves the timeliness and effectiveness of heat exchange, and solves the technical problems of drive motors in related technologies, such as large overall size, high manufacturing cost and insufficient cooling efficiency due to the dispersed structure, many parts and complex pipes of the oil circuit cooling system.

[0024] In some preferred embodiments, the oil pump assembly 5 includes a first oil pump 51 and a second oil pump 52 symmetrically arranged on both sides of the bottom of the oil tank 2; the oil inlets of the first oil pump 51 and the second oil pump 52 are both connected to the oil tank 2, and the oil outlets of the first oil pump 51 and the second oil pump 52 are connected to the inlet end of the oil cooler 6 after being merged through parallel pipelines.

[0025] In this embodiment, the single oil pump supply scheme has two major drawbacks. First, when a high-power motor operates under high load, the oil supply flow of a single oil pump may be insufficient, resulting in insufficient distribution of cooling oil in the stator and rotor oil circuits, failing to meet the heat dissipation needs of the core heat-generating areas. Second, if a single oil pump fails, the entire cooling system will be paralyzed, severely affecting the reliability of motor operation. Therefore, the parallel connection of two oil pumps can significantly increase the total oil supply flow, ensuring that both the stator and rotor oil circuits receive sufficient cooling oil when the motor operates at high power, avoiding localized overheating due to insufficient oil supply. The parallel design also has redundancy; if one oil pump fails, the other can still maintain basic oil supply, reducing the risk of overall cooling system failure and improving the reliability of motor operation.

[0026] In some preferred embodiments, an oil collecting ring is connected to the end of the stator oil passage 3, and the oil collecting ring is located at the end of the winding. The oil collecting ring has an annular cavity inside and multiple radial injection holes are opened on the oil collecting ring. The annular cavity is connected to the stator oil passage 3 so as to spray the cooling oil to the winding end 7 through the radial injection holes.

[0027] In this embodiment, the annular cavity of the oil collecting ring can temporarily store and buffer the cooling oil transported by the stator oil circuit, ensuring stable oil pressure and sufficient cooling. Multiple radial injection holes are distributed along the circumferential direction of the oil collecting ring, which can directionally and evenly spray the cooling oil to various areas of the winding end, solving the problems of local accumulation and insufficient cooling oil throughout the entire area in the traditional solution. The radial injection method allows the cooling oil to directly impact the heat-generating surface of the winding end, which significantly improves the heat exchange efficiency between the oil and the winding and reduces the loss of ineffective flow of cooling oil. The close arrangement of the oil collecting ring and the winding end shortens the injection path of the cooling oil, reduces the pressure loss of the oil during the flow process, ensures stable injection pressure, and further improves the cooling reliability.

[0028] In some preferred embodiments, the radial injection holes are distributed along the circumferential direction of the oil collecting ring, and a dense group of injection holes is provided in the ring segment corresponding to the high-temperature region of the winding end 7.

[0029] In this embodiment, the dense spray nozzle group can increase the amount of cooling oil sprayed in the high-temperature area, improve the oil coverage and heat exchange frequency in the area, directly reduce the local temperature, and avoid winding damage caused by local overheating. Unlike the uniform distribution of uniform spray, this design optimizes the distribution efficiency of cooling oil through differentiated oil supply without increasing the total oil supply flow, thus reducing energy waste. After targeted enhancement of cooling in the high-temperature area, the overall temperature distribution of the motor is more uniform, which can reduce the thermal stress of the winding caused by excessive temperature gradient and extend the service life of the motor.

[0030] In some preferred embodiments, an oil guide cover 8 is also included, which is fixed to the rotor end face; a shaft oil passage is provided inside the rotor assembly; the rotor oil passage 4 is connected to the shaft oil passage through the back flow channel of the oil guide cover 8, so as to allow the cooling oil to be thrown to the winding end 7 when the rotor rotates at high speed.

[0031] In this embodiment, the back channel of the oil guide cover 8 provides a directional delivery channel for the cooling oil, allowing the cooling oil to flow smoothly from the rotor oil passage 4 into the axial oil passage of the rotor assembly, avoiding losses caused by disordered oil flow and ensuring that the cooling oil accurately reaches the rotor end area. When the rotor rotates at high speed, the cooling oil in the axial oil passage is thrown out radially under the action of centrifugal force, directly acting on the winding end 7. Combined with the closed structure of the oil guide cover 8, it reduces the leakage of cooling oil to non-target areas and improves the utilization rate of cooling oil. The fixed connection between the oil guide cover 8 and the rotor end face enhances the sealing of the oil passage, reduces the risk of leakage of cooling oil during the delivery process, and ensures the pressure stability of the rotor oil passage. This structure combines the oil guiding function with the rotor end face protection function, eliminating the need for additional guiding components and simplifying the structure of the rotor assembly.

[0032] In some preferred embodiments, an oil guide cover plate 8 is also included, which is fixed to the rotor end face; the rotor assembly is provided with a shaft oil passage; the surface of the oil guide cover plate 8 facing the winding end is provided with an oil throwing groove, which is connected to the shaft oil passage; the oil throwing groove is a groove radiating outward from the shaft center of the oil guide cover plate 8, and the groove depth gradually decreases from the inner diameter to the outer diameter.

[0033] In this embodiment, the radial grooves provide a directional flow path for the cooling oil, allowing it to diffuse evenly from the axis to the radial direction along the grooves, avoiding local accumulation and ensuring that all areas at the winding ends receive cooling oil. The groove depth, with the inner groove being deeper and the outer groove shallower, matches the centrifugal force law. As the rotor rotates, the centrifugal force increases with the radius. The deeper inner grooves can hold more cooling oil, while the shallower outer grooves utilize centrifugal force to accelerate the oil ejection, improving the oil ejection speed and flow stability. Directional oil ejection reduces ineffective losses from oil splashing, allowing the cooling oil to impact the winding ends in a more concentrated manner, increasing the contact time and area between the oil and the winding, and significantly improving heat exchange efficiency.

[0034] In some preferred embodiments, the oil cooler 6 is installed on the top of the housing 1, and its outlet end is connected to the stator oil passage 3 and the rotor oil passage 4 respectively through the branch pipe 9.

[0035] In this embodiment, the branch pipe 9 directly branches from the oil cooler outlet to the dual oil circuit without the need for additional branch connectors, which simplifies the pipeline structure, reduces leakage points, and improves the oil circuit sealing performance.

[0036] In some preferred embodiments, the bottom of the oil tank 2 is provided with an inclined guide surface, and the oil inlet of the oil pump assembly 5 is located at the lowest point of the inclined guide surface; the side wall of the housing 1 is provided with guide ribs to allow the cooling oil to flow back to the oil tank 2 along the guide ribs.

[0037] In this embodiment, the inclined guide surface causes the cooling oil returning to the oil sump to gather at the lowest point under the action of gravity, ensuring that the oil pump inlet can always draw in sufficient cooling oil, avoiding the problem of dry suction, and improving the oil supply stability of the oil pump; the guide ribs on the side wall of the casing provide a directional return path for the cooling oil, guiding the oil adhering to the wall surface to flow quickly to the oil sump, reducing the oil return time and improving the overall efficiency of the cooling cycle; the improved oil return efficiency accelerates the circulation speed of the cooling oil between the oil sump, oil pump, oil cooler, and dual oil circuits, increasing the amount of cooling oil flowing through the heat-generating area per unit time, and significantly enhancing the heat dissipation effect.

[0038] In some preferred embodiments, a temperature sensor assembly and a controller are also included; the temperature sensor assembly is located in the axial region of the stator assembly and the rotor assembly; the controller is signal-connected to the oil pump assembly 5 and the temperature sensor assembly respectively, for adjusting the output power of the oil pump assembly 5 according to the temperature signal.

[0039] In this embodiment, a temperature sensor monitors the temperature of the stator core and rotor shaft in real time, providing accurate temperature feedback for the cooling system and solving the problem of blind oil supply. The controller dynamically adjusts the output power of the oil pump based on the temperature signal. At low temperatures, the oil pump speed is reduced, the oil supply flow is decreased, and energy consumption is reduced. At high temperatures, the speed is increased, the oil supply flow is increased, and the heat dissipation effect is ensured, achieving on-demand cooling. The temperature monitoring function can provide real-time feedback on the temperature status of the core components of the motor, facilitating early warning of potential overheating faults, providing data support for motor maintenance, extending the service life of the motor, and reducing later maintenance costs.

[0040] Secondly, this application also proposes an oil-cooled motor with an oil circuit structure for its application design.

[0041] The beneficial effects of this invention include: An oil circuit structure for an oil-cooled motor is provided, wherein the motor housing 1 integrates the stator oil circuit channel 3 and the rotor oil circuit channel 4, integrating the oil circuit structure that might have been set independently into the motor housing 1, eliminating the complex external oil pipes or scattered internal oil channels in the traditional solution, and reducing the space occupied by the dispersed arrangement of components; the oil cooler 6 is directly set on the motor housing 1, and the oil pump assembly 5 is connected to the oil sump 2 and the oil cooler 6 through an integrated channel, avoiding the dispersed installation of independent components, making the overall structure more compact and effectively reducing the size of the motor. By integrating the stator and rotor oil circuits through the motor housing 1, the use of additional pipes, connectors and other auxiliary components is reduced; the stator oil circuit channel 3 extends to the stator assembly area and the rotor oil circuit channel 4 extends to the rotor assembly area, ensuring that the cooling oil can be accurately delivered to the core heat-generating areas; after being cooled by the oil cooler 6, the cooling oil is divided into two paths to the stator and rotor areas, and then flows back to the oil sump 2 to form a cycle, which improves the timeliness and effectiveness of heat exchange, and solves the technical problems of drive motors in related technologies, such as large overall size, high manufacturing cost and insufficient cooling efficiency due to the dispersed structure, many parts and complex pipes of the oil circuit cooling system.

[0042] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are 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. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0043] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0044] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. An oil circuit structure for an oil-cooled motor, characterized in that, It includes: The motor housing (1) has an oil sump (2) at its bottom; the motor housing (1) integrates a stator oil passage (3) and a rotor oil passage (4); the stator oil passage (3) penetrates the motor housing (1) and extends to the stator assembly area, and the rotor oil passage (4) penetrates the motor housing (1) and extends to the rotor assembly area; An oil cooler (6) is provided on the motor housing (1); The oil pump assembly (5) has its inlet connected to the oil sump (2) and its outlet connected to the inlet of the oil cooler (6) to deliver high-temperature oil to the oil cooler (6); the outlet of the oil cooler (6) is connected to the stator oil passage (3) and the rotor oil passage (4) to deliver cooling oil to the stator assembly area and the rotor assembly area respectively, and return it to the oil sump (2) to form an oil cooling cycle.

2. The oil circuit structure of the oil-cooled motor as described in claim 1, characterized in that: The oil pump assembly (5) includes a first oil pump (51) and a second oil pump (52) symmetrically arranged on both sides of the bottom of the oil tank (2); The oil inlets of the first oil pump (51) and the second oil pump (52) are connected to the oil sump (2), and the oil outlets of the first oil pump (51) and the second oil pump (52) are connected to the inlet of the oil cooler (6) after being merged through parallel pipelines.

3. The oil circuit structure of the oil-cooled motor as described in claim 1, characterized in that: The stator oil passage (3) is connected to an oil collecting ring at its end, and the oil collecting ring is located at the end of the winding. The oil collecting ring has an annular cavity inside and multiple radial injection holes are opened on the oil collecting ring. The annular cavity is connected to the stator oil passage (3) so that the cooling oil can be sprayed to the winding end (7) through the radial injection holes.

4. The oil circuit structure of the oil-cooled motor as described in claim 3, characterized in that: The radial injection holes are distributed along the circumferential direction of the oil collecting ring, and a dense group of injection holes is provided in the ring segment corresponding to the high temperature region at the end of the winding (7).

5. The oil circuit structure of the oil-cooled motor as described in claim 1, characterized in that: It also includes an oil guide cover (8), which is fixed to the rotor end face; the rotor assembly is provided with a shaft oil passage; The rotor oil passage (4) is connected to the shaft oil passage through the back flow channel of the oil guide cover (8) so that the cooling oil can be thrown to the winding end (7) when the rotor rotates at high speed.

6. The oil circuit structure of the oil-cooled motor as described in claim 1, characterized in that: It also includes an oil guide cover (8), which is fixed to the rotor end face; the rotor assembly is provided with a shaft oil passage; The surface of the oil guide cover (8) facing the winding end is provided with an oil throwing groove, which is connected to the shaft oil passage; The oil slinger is a groove radiating outward from the axis of the oil guide cover (8), and the groove depth gradually decreases from the inner diameter to the outer diameter.

7. The oil circuit structure of the oil-cooled motor as described in claim 1, characterized in that: The oil cooler (6) is installed on the top of the housing (1), and its outlet end is connected to the stator oil passage (3) and the rotor oil passage (4) respectively through the branch pipe (9).

8. The oil circuit structure of the oil-cooled motor as described in claim 1, characterized in that: The bottom of the oil tank (2) is provided with an inclined guide surface, and the oil inlet of the oil pump assembly (5) is located at the lowest point of the inclined guide surface; The side wall of the housing (1) is provided with guide ribs to allow the cooling oil to flow back to the oil sump (2) along the guide ribs.

9. The oil circuit structure of the oil-cooled motor as described in claim 1, characterized in that: It also includes temperature sensor components and a controller; The temperature sensor assembly is located in the central region of the stator assembly and the rotor assembly; The controller is connected to the oil pump assembly (5) and the temperature sensor assembly respectively, so as to adjust the output power of the oil pump assembly (5) according to the temperature signal.

10. An oil-cooled motor, characterized in that, It includes the oil passage structure as described in any one of claims 1-9.

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