Oil-cooled electric drive end cover structure, electric drive shell and electric drive assembly

Abstract

This invention discloses an oil-cooled electric drive end cover structure, an electric drive housing, and an electric drive assembly, belonging to the technical field of electric drive systems. It includes: a rear end cover for fixing to the end of the motor housing; a filter installed on the lower axial side of the rear end cover; a main oil passage located inside the rear end cover, with its inlet end connected to the filter outlet end; and an oil cooler installed on the upper axial side of the rear end cover, with its oil inlet connected to the main oil passage outlet end, and its oil outlet connected to a cooling oil passage inside the motor housing. The oil cooler also has coolant inlet and outlet. This invention highly integrates the filter, main oil passage, and oil cooler into the rear end cover, simplifying the motor housing structure and reducing processing difficulty. This invention constructs a complete priority cooling circuit, ensuring precise temperature control of core components and significantly improving the integration, cooling effect, and maintenance convenience of the electric drive assembly.

Description

Technical Field

[0001] This invention relates to the field of electric drive system technology for new energy vehicles, and more specifically, to an oil-cooled electric drive end cover structure, an electric drive housing including the end cover structure, and an electric drive assembly. Background Technology

[0002] With the increasing popularity of new energy vehicles, the market demand for the performance of electric vehicle power systems is constantly increasing, and the requirements for the size and power density of electric drive systems are also becoming higher. This means that the power system structure needs to be as compact and lightweight as possible; coaxial electric drives belong to this type of highly integrated electric drive product. In addition, the space available in vehicles is currently limited, requiring water and oil channels to be highly centralized and not dispersed, while also facilitating the placement of other functional components.

[0003] For example, the Chinese invention patent with patent number "CN112421889B" entitled "A Three-in-One Oil-Cooled Electric Drive Structure" describes an electric drive structure including a reducer-to-motor rear-end oil cooling structure, a rotor cooling structure, and a stator cooling structure integrated with the electric drive housing. The reducer-to-motor rear-end oil cooling structure delivers cooling oil from the reducer housing to the main oil circuit of the motor housing. The main oil circuit is divided into a first oil circuit and a second oil circuit at the rear end cover. The first oil circuit connects to the stator cooling structure, and the second oil circuit connects to the rotor cooling structure. The stator cooling structure introduces cooling oil above the electric drive and provides directional cooling to the stator through oil spray holes in the stator oil channel on the motor housing. The rotor cooling structure achieves cooling by rotating the rotor and splashing the cooling oil. This electric drive structure utilizes the housing's own structural design to connect the circulating oil circuit and divides the oil circuit on the housing, ensuring cooling of the stator and rotor. It eliminates the need for additional oil distribution structures and copper pipes, improving the integration of the oil-cooled electric drive, reducing costs, and minimizing the risk of oil leakage.

[0004] However, this structure also has some problems. It concentrates the main cooling components on the motor housing, making the entire motor housing structure quite complex. On the one hand, this increases the difficulty of manufacturing the motor housing, and on the other hand, once the functional components on the motor housing are damaged after assembly, they are not easy to replace or repair. Summary of the Invention

[0005] The present invention aims to solve the technical problems of complex housing structure, difficult processing and inconvenient maintenance caused by the integration of electric drive cooling systems into the motor housing in the prior art, and provides a highly integrated, easy-to-maintain and highly efficient oil-cooled electric drive end cover structure, electric drive housing and electric drive assembly.

[0006] The technical solution of the present invention is: an oil-cooled electric drive end cover structure, comprising: The rear end cover is fixed to the axial end of the motor housing; A filter is installed on the lower axial outer side of the rear end cover; The main oil passage is located inside the rear end cover, and the inlet end of the main oil passage is connected to the outlet end of the filter. An oil cooler is installed on the upper axial outer side of the rear end cover. The oil inlet of the oil cooler is connected to the outlet end of the main oil passage, and the oil outlet of the oil cooler is used to connect to the cooling oil passage inside the motor housing. The oil cooler is also provided with a cooling water inlet and a cooling water outlet.

[0007] According to an oil-cooled electric drive end cover structure provided by the present invention, the rear end cover is provided with a mounting groove for installing the filter; the end of the mounting groove facing away from the motor housing is open.

[0008] According to the present invention, in an oil-cooled electric drive end cover structure, the main oil passage is located inside the rear end cover near the outer circumference of the rear end cover.

[0009] According to an oil-cooled electric drive end cap structure provided by the present invention, the main oil passage includes a first oil passage section connecting the filter and a second oil passage section connecting the oil cooler; the outlet end of the first oil passage section and the inlet end of the second oil passage section are connected to form a bent main oil passage.

[0010] According to the oil-cooled electric drive end cover structure provided by the present invention, the axes of the first oil passage segment and the second oil passage segment are both perpendicular to the axis of the motor housing, and the intersection angle between the axis of the first oil passage segment and the axis of the second oil passage segment is not greater than 90°.

[0011] According to the oil-cooled electric drive end cover structure provided by the present invention, the oil inlet, oil outlet, cooling water inlet and cooling water outlet on the oil cooler are respectively located at the four corners of the oil cooler, and the line connecting the oil inlet and oil outlet intersects the line connecting the cooling water inlet and cooling water outlet.

[0012] According to an oil-cooled electric drive end cap structure provided by the present invention, the oil inlet is located above the oil outlet; and the cooling water inlet is located below the cooling water outlet.

[0013] The present invention also relates to an electric drive housing, comprising: The oil-cooled electric drive end cap structure as described in any one of claims 1 to 7; The motor housing has stator cooling oil passages and rotor cooling oil passages that are respectively connected to the oil outlet of the oil cooler. A reducer housing is installed on the other axial end of the motor housing relative to the rear end cover, and a differential cooling oil passage is provided inside the reducer housing, which is connected to the oil outlet of the oil cooler.

[0014] According to an electric drive housing provided by the present invention, an oil pump is also included; the oil pump is installed on the lower outer side of the motor housing, and the outlet end of the oil pump is connected to the inlet end of the filter.

[0015] The present invention also relates to an electric drive assembly, the electric drive assembly including the electric drive housing described above.

[0016] The advantages of this invention are as follows: 1. This invention integrates the three core functional modules—filter, main oil passage, and oil cooler—onto a single rear end cover. This plug-and-play modular design greatly saves valuable space inside and outside the motor housing. The motor housing itself only needs to provide basic cooling oil passages, eliminating the need for complex internal structures and mounting points to accommodate these accessories, making the design of the motor housing itself simpler and more compact. 2. This invention defines the installation positions of each component: the filter is at the bottom, and the oil cooler is at the top. This layout is ingenious, conforming to the principles of gravity and the system's working logic. After cooling and filtration, the oil is naturally in a ready-to-use state, ready to enter the motor for lubrication and cooling at any time. However, the top-to-bottom layout avoids interference between components, making the entire end cover structure clearly layered and easy to assemble and connect pipes. This invention constructs a complete and orderly closed-loop cooling oil circuit through the interconnection of the filter, main oil passage, oil cooler, and motor cooling oil passage. All oil entering the motor must be filtered and cooled, fundamentally ensuring the cleanliness and low temperature of the oil entering the motor. This invention sets the main oil passage inside the rear end cover, rather than using an external hose or steel pipe, making the oil path shortest and the bends fewest. A large-diameter main oil passage can be used. This built-in and short main oil passage design can significantly reduce the resistance of oil flow, reduce pumping losses, and improve the efficiency of the entire cooling system. 2. This invention achieves external mounting of the filter by setting an opening facing away from the motor housing. When the filter needs to be replaced after long-term vehicle operation, maintenance personnel do not need to disassemble the rear cover, motor, or any heavy high-voltage wiring harness. They can easily remove and replace the filter directly from the bottom of the vehicle (for electric drive assemblies located under the vehicle body) or from the outside of the motor end. This design minimizes maintenance time and cost, significantly improving the user-friendliness of the product. 3. The present invention arranges the main oil passage near the outer circumference of the rear end cover, which has a dual advantage. On the one hand, this allows the main oil passage to be as close as possible to the filter outlet and oil cooler inlet, shortening the connection path and making the internal flow channel design smoother. On the other hand, the outer circumference area of ​​the end cover is usually a location with high structural strength. Setting a large-diameter main oil passage here can maximize the oil passage diameter while ensuring structural strength, thereby achieving the goal of reducing flow resistance. At the same time, it avoids structural weakening of the central area of ​​the end cover (which may be used to install bearings, shaft seals, etc.) due to the opening of the oil passage. 4. The present invention designs the main oil passage as a bent structure consisting of two sections to better accommodate the two functional components located at the lower end (filter) and the upper end (oil cooler). The axes of the two oil passage sections are defined to be perpendicular to the motor axis, and the intersection angle is no greater than 90°. This allows the oil to change direction as it flows from the lower end to the upper end. However, this smooth turn of no more than 90° finds the best balance between accommodating component layout and controlling flow resistance within the limited space of the rear end cover. This is more advantageous than a completely straight oil passage that cannot be arranged, or an oil passage with sharp turns that cause a sharp increase in flow resistance. 6. This invention places the oil and water inlets and outlets at the four corners and makes their connecting lines intersect, which forces the oil and cooling water to cross the flow paths inside the oil cooler. By allowing the oil to flow from top to bottom and the cooling water to flow from bottom to top, this cross-flow counter-current heat exchange method can form a more uniform and efficient temperature field on the entire heat exchange core compared to the simple co-flow or single-sided inlet and outlet method. It maximizes the use of cooling water to absorb the heat of the oil, thereby significantly improving the heat exchange efficiency per unit volume. 7. This invention clarifies how the cooling oil, after being filtered and cooled in the end cap, is distributed to the stator and rotor of the motor and finally flows to the differential of the reducer. All key heat-generating components (stator, rotor, reducer) receive fresh cold oil that has been fully cooled by the oil cooler, thus maximizing the cooling effect. 8. This invention clarifies the complete oil circuit circulation of oil pump, filter, main oil passage, oil cooler, and motor / reducer; by installing the oil pump at the lower end of the outer side of the motor housing, it is not only convenient for the oil pump to draw oil from the oil tank (usually located at the lowest point of the system), but also compactly connects the filter. The entire system forms a series loop with clear logic, shortest path, and least pressure loss, reflecting an extremely high level of system integration design. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of the electric drive housing in an embodiment of the present invention; Figure 2 for Figure 1 A cross-sectional structural diagram of the middle and rear end caps shows the direction of the internal main oil passages; Figure 3 This is a schematic diagram of the structure of the oil cooler in an embodiment of the present invention, showing the inlet and outlet positions of the oil and cooling water; Figure 4 This is a schematic diagram of the arrangement of cooling oil channels inside the motor housing in an embodiment of the present invention; Wherein: 1—rear end cover; 2—motor housing; 3—reducer housing; 4—oil pump; 5—filter; 6—oil cooler; 11—Main oil passage; 12—Cooling water passage; 13—Stator cooling oil passage; 14—Rotor cooling oil passage; 15—Differential cooling oil passage. Detailed Implementation

[0018] Embodiments of the present invention are described in detail below, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0019] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention 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. Therefore, they should not be construed as limitations on this invention.

[0020] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0021] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0022] This invention relates to an oil-cooled electric drive end cover structure, electric drive housing, and assembly. The core of this invention lies in achieving a high degree of integration and optimization of the cooling system through the rear end cover. This invention overcomes the limitations of traditional distributed layouts, pioneering a technical solution for functional integration and flow channel optimization using the end cover as a carrier. By integrating the filter, oil cooler, and main oil passage into the rear end cover, system modularity is achieved. Through the built-in large-diameter bent main oil passage and cross-counterflow oil cooler, low flow resistance and high heat exchange efficiency are simultaneously achieved within a very small space. The resulting full-process priority cooling loop ensures precise temperature control of core components. This significantly improves the power density, cooling effect, and maintenance convenience of the electric drive assembly, demonstrating extremely high integrated innovation value.

[0023] Specifically, such as Figures 1-4 As shown, the core of the oil-cooled electric drive end cover structure of the present invention lies in providing a highly integrated rear end cover unit. For example... Figure 1 and 2As shown, the structure includes a rear end cover 1, a filter 5, a built-in main oil passage 11, and an oil cooler 6. The rear end cover 1 is fixed to the axial end of the motor housing 2. The filter 5 is installed on the lower axial side of the rear end cover 1. The main oil passage 11 is located inside the rear end cover 1, and its inlet end is connected to the outlet end of the filter 5. The oil cooler 6 is installed on the upper axial side of the rear end cover 1, and its oil inlet is connected to the outlet end of the main oil passage 11. The oil outlet is used to connect with the cooling oil passages (such as the stator cooling oil passage 13 and the rotor cooling oil passage 14) inside the motor housing 2. In addition, the oil cooler 6 is also provided with a cooling water inlet and a cooling water outlet for introducing coolant.

[0024] This invention integrates all the traditionally dispersed filtration, flow guiding, and cooling functional modules into a specially designed rear end cover 1. Hot oil pumped from the oil pump 4 first enters the filter 5 for impurity filtration, ensuring oil cleanliness. The filtered clean oil then directly enters the main oil passage 11, cast or machined inside the rear end cover 1. This main oil passage 11 acts as a large-volume oil reservoir and distribution hub, smoothly guiding the oil to the upper oil cooler 6. In the oil cooler 6, the hot oil undergoes efficient heat exchange with cooling water from the cooling water inlet. The cooled oil then enters the motor housing 2 through the oil outlet, precisely cooling the stator and rotor, and other heat-generating components.

[0025] In practical applications, when the electric drive assembly is running, the oil pump 4 starts, drawing lubricating oil from the oil tank (not shown in the figure). The lubricating oil first enters the filter 5 to remove mechanical impurities. Subsequently, the clean oil flows into the main oil passage 11 inside the rear end cover 1. Guided by the main oil passage 11, the oil flows upward and enters the oil cooler 6. At the same time, externally circulating cooling water also enters the oil cooler 6, carrying away the heat from the oil. The cooled oil finally leaves the oil cooler 6 and flows into the various cooling oil passages inside the motor housing 2, completing the lubrication and cooling of the motor and / or reducer components.

[0026] This invention constructs a modular, highly integrated end cap structure. Its advantages include: extremely high integration and compactness, integrating the filter 5, main oil passage 11, and oil cooler 6 all into the rear end cap 1, greatly freeing up internal and external space in the motor housing 2, allowing for a simpler design. Simultaneously, the clear functional partitioning (filter below, oil cooler above) conforms to the system's operating logic and facilitates assembly. The built-in large-diameter main oil passage 11 significantly reduces oil flow resistance and improves system efficiency. Most importantly, it establishes a highly efficient cooling circulation foundation for the filter, main oil passage, oil cooler, and motor, ensuring that the oil entering the motor is always clean and at a low temperature.

[0027] In some embodiments of the present invention, the rear cover 1 structure described above has been further optimized. Specifically, as follows: Figure 1 and 2 As shown, the rear cover 1 has a mounting slot specifically for installing the filter 5. The opening of this mounting slot (i.e., the end facing away from the motor housing 2) is open so that the filter 5 can be directly inserted or removed from the outside.

[0028] This embodiment optimizes the installation method of filter 5, making it a module that can be disassembled and installed independently of the rear cover 1 and the motor housing 2. By installing filter 5 externally in an open mounting slot, maintenance and replacement of the filter no longer require disassembly of any surrounding large components.

[0029] After the vehicle has traveled a certain mileage, filter 5 needs to be maintained and replaced. Maintenance personnel do not need to disassemble the rear cover 1, motor housing 2, or any high-voltage wiring harness. They simply need to access the filter 5 directly from the outside of the electric drive assembly, and remove the old filter 5 by a simple rotation or plugging action, then install the new filter 5. The entire operation is quick and simple.

[0030] This installation structure makes filter maintenance exceptionally simple and quick, greatly reducing users' later usage costs and repair time, and significantly enhancing the product's market competitiveness.

[0031] In other embodiments of the present invention, the structure of the main oil passage 11 described above has been optimized. For example... Figure 1 and 2 As shown, the main oil passage 11 is not a simple straight channel, but is located inside the rear end cover 1 near its outer circumference. The main oil passage 11 is formed by drilling inside the rear end cover 1; that is, the main oil passage 11 is not a separate pipe structure, but is integrated inside the rear end cover 1. More specifically, the main oil passage 11 includes a first oil passage section connecting to the filter 5 and a second oil passage section connecting to the oil cooler 6. The outlet end of the first oil passage section is connected to the inlet end of the second oil passage section, together forming a bent main oil passage 11. Ideally, the axes of both the first and second oil passage sections are perpendicular to the axis of the motor housing 2, and the intersection angle α between them is no greater than 90°.

[0032] In this embodiment, within the limited space of the rear end cover 1, the routing of the main oil passage 11 is carefully designed to optimize structural strength and fluid performance. The main oil passage 11 is positioned near the outer circumference, utilizing the high structural strength of this area and avoiding weakening the structure of the central region of the end cover. The main oil passage is designed as a two-section bent structure to spatially connect the two components located at the lower end (filter 5) and the upper end (oil cooler 6). Controlling the bending angle to within 90° represents a balance between adapting to the spatial layout and controlling flow resistance.

[0033] In practical applications, the oil filtered by filter 5 first enters the first oil passage section. After reaching the outlet of the first oil passage section, the oil enters the second oil passage section connected to it, where the flow direction changes by no more than 90°, turning upward or diagonally upward, and finally reaching the inlet of the oil cooler 6.

[0034] In this embodiment, the design of the main oil passage 11 ensures that it has sufficient space to be enlarged to reduce flow resistance, while avoiding any impact on the structural strength of the central functional area of ​​the end cap (such as the bearing housing). The bent main oil passage 11 and its bending angle of no more than 90° achieve an optimal balance between space constraints and fluid efficiency, realizing a smooth, low-resistance connection from the lower filter to the upper oil cooler, demonstrating the ingenuity of the design.

[0035] In a preferred embodiment of the present invention, the internal flow channel design of the oil cooler 6 has been optimized. For example... Figure 3 As shown, the oil inlet on the oil cooler 6 (e.g.) Figure 3 A) Oil outlet (as shown) Figure 3 As shown in B), cooling water inlet (such as...) Figure 3 As shown in C) and cooling water outlet (e.g. Figure 3 As shown in Figure D), the oil coolers 6 are positioned at their four corners. The line connecting the oil inlet and outlet intersects spatially with the line connecting the cooling water inlet and outlet. Preferably, the oil inlet is located above the oil outlet, while the cooling water inlet (connected to the cooling water channel 12, such as...) Figure 2 (As shown) is located below the cooling water outlet.

[0036] This embodiment maximizes heat exchange efficiency by forcing the oil and coolant to flow in a cross-counterflow pattern inside the oil cooler 6. The oil enters from the top and flows downward under gravity; the cooling water enters from the bottom and flows upward under the pressure of the water pump. The flow paths of the two intersect in the heat exchange core, forming a maximized temperature gradient field, enabling heat to be efficiently transferred from the oil to the cooling water.

[0037] In practical applications, during the operation of the electric drive system, high-temperature oil enters the oil cooler 6 through the upper oil inlet and flows to the lower oil outlet within the internal heat exchange core. Simultaneously, low-temperature cooling water enters the oil cooler 6 through the lower cooling water inlet and flows to the upper cooling water outlet within the heat exchange core. This cross-current counter-current heat exchange between the oil and cooling water within the heat exchange core achieves efficient heat transfer. The cooled oil then flows out from the oil outlet to the motor and reducer.

[0038] This oil cooler design in this embodiment significantly improves heat exchange efficiency. By placing the inlet and outlet of the oil and cooling water at the four corners and connecting them with intersecting lines, cross-current heat exchange is cleverly achieved. This design makes the temperature field distribution inside the heat exchanger more uniform, and the heat exchange temperature difference is always maintained at a high level, thus removing more heat with the same volume and flow rate.

[0039] In some embodiments of the present invention, this embodiment also relates to an electric drive housing, which extends the aforementioned end cap structure to the entire electric drive housing and integrates an oil pump. For example... Figure 1 and 4 As shown, an electric drive housing includes: an oil-cooled electric drive end cover structure as described in any of the previous embodiments; a motor housing 2; and a reducer housing 3. The motor housing 2 has a stator cooling oil passage 13 and a rotor cooling oil passage 14, respectively connected to the oil outlet of an oil cooler 6. The reducer housing 3 is mounted on the other axial end of the motor housing 2 relative to the rear end cover 1, and has a differential cooling oil passage 15 inside that connects to the outlet end of the stator cooling oil passage 13. Furthermore, it includes an oil pump 4, which is mounted on the lower outer side of the motor housing 2 (the motor housing 2 has a mounting groove specifically for mounting the oil pump 4, similar to the mounting groove structure of the filter described above), and its outlet end connects to the inlet end of the filter 5.

[0040] A hole is drilled inside the motor housing 2 to form a housing oil passage. Branch oil passages are provided on the housing oil passage, namely stator cooling oil passage 13, rotor cooling oil passage 14 and differential cooling oil passage 15.

[0041] This embodiment constructs a complete, top-down integrated thermal management system. Oil pump 4, as the power source, draws oil from the lowest point of the system. The oil is pumped into the filter 5 and oil cooler 6 integrated on the rear end cover 1 for purification and cooling. The cooled, clean oil is distributed to the motor housing 2, with a portion entering the stator cooling oil passage 13 and the other portion entering the rotor cooling oil passage 14. After completing stator cooling, the oil continues to flow downwards under gravity, entering the differential cooling oil passage 15 within the reducer housing 3 to lubricate and cool the differential gears. Finally, all the oil that has completed its task collects at the bottom of the housing and is drawn back in by oil pump 4, forming a complete cycle.

[0042] This embodiment deeply integrates the advantages of the end cover structure with the entire electric drive housing, realizing the construction of a complete, priority-cooling integrated thermal management system. Its core advantage lies in the fact that all heat-generating components requiring cooling (stator, rotor, differential) receive fresh, cold oil that has been fully cooled by the oil cooler 6, maximizing the cooling effect. Simultaneously, by integrating the oil pump 4, filter 5, oil cooler 6, and other components onto the motor housing 2 and the rear end cover 1, a logically clear, shortest-path, and least-pressure-loss series circuit is formed, demonstrating an extremely high level of system integration design.

[0043] This invention also relates to an electric drive assembly, which includes the electric drive housing described in the above embodiments. This embodiment applies all the aforementioned innovative housing structures to the final electric drive assembly product. The electric drive assembly using this housing naturally inherits all the aforementioned advantages: high cooling efficiency, compact structure, low system flow resistance, convenient maintenance, and high reliability. This gives the electric drive assembly a significant competitive advantage in terms of power density, energy efficiency, service life, and subsequent maintenance costs.

[0044] Specifically, the electric drive assembly of the present invention includes an electric drive housing, which is formed by sequentially connecting a rear end cover 1, a motor housing 2, and a reducer housing 3 along the axial direction.

[0045] A filter 5 is installed at the lower axial outer end of the rear end cover 1 through an open mounting slot, facilitating external replacement. An oil cooler 6 is installed at the upper axial outer end of the rear end cover 1. The oil cooler 6 adopts a cross-counterflow design, with the oil inlet at the top and the oil outlet at the bottom; the cooling water inlet is at the bottom and the cooling water outlet at the top, positioned at the four corners to improve heat exchange efficiency. Inside the rear end cover 1, near the outer circumference, a curved main oil passage 11 is cast or machined. This main oil passage 11 consists of a first oil passage section and a second oil passage section, with an included angle of no more than 90°, connecting the outlet of the filter 5 and the inlet of the oil cooler 6, respectively.

[0046] An oil pump 4 is installed on the lower outer side of the motor housing 2, and the outlet of the oil pump 4 is directly connected to the inlet of the filter 5. The motor housing 2 has independent stator cooling oil passages 13 and rotor cooling oil passages 14, and the inlets of both are connected to the oil outlet of the oil cooler 6.

[0047] The reducer housing 3 is provided with a differential cooling oil passage 15, the inlet of which is connected to the outlet of the stator cooling oil passage 13 in the motor housing 2.

[0048] During actual operation, when the electric drive assembly is running, the oil pump 4 starts, drawing in the high-temperature lubricating oil from the oil sump at the bottom of the reducer housing 3 or motor housing 2. The high-temperature oil is first pumped into the filter 5 installed at the lower end of the rear end cover 1, where all mechanical impurities are filtered out. The clean oil then enters the first oil passage section inside the rear end cover 1, flowing horizontally. Upon reaching the end, the oil smoothly turns (angle ≤ 90°) and enters the second oil passage section, being guided upwards to the inlet of the oil cooler 6. The oil enters the oil cooler 6 from above. Simultaneously, low-temperature coolant from the vehicle's cooling system enters the oil cooler 6 from below. The oil flows downwards, and the coolant flows upwards, forming a highly efficient cross-countercurrent heat exchange in the heat exchange core, causing the oil temperature to drop rapidly. The cooled, clean oil flows out from the outlet of the oil cooler 6 and enters the motor housing 2. The oil enters the stator cooling oil passage 13 to cool the stator core and windings. After completing the stator cooling task, the oil, at a certain temperature, flows out of the motor housing 2 under gravity and enters the differential cooling oil passage 15 inside the reducer housing 3 to lubricate and cool the differential gears and bearings. It then enters the rotor cooling oil passage 14, where oil is typically introduced into the rotor shaft via a rotary joint or similar means to cool the rotor magnets and other components. After completing the lubrication and cooling of all components, the oil finally collects at the lowest point (oil sump) at the bottom of the housing under gravity, awaiting re-intake by the oil pump 4 to begin the next cycle.

[0049] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. An oil-cooled electric drive end cover structure, characterized in that: include: The rear end cover (1) is fixed to the axial end of the motor housing (2); The filter (5) is installed on the lower axial outer side of the rear end cover (1); The main oil passage (11) is located inside the rear end cover (1), and the inlet end of the main oil passage (11) is connected to the outlet end of the filter (5). An oil cooler (6) is installed on the upper axial side of the rear end cover (1). The oil inlet of the oil cooler (6) is connected to the outlet of the main oil passage (11). The oil outlet of the oil cooler (6) is used to connect with the cooling oil passage in the motor housing (2). The oil cooler (6) is also provided with a cooling water inlet and a cooling water outlet.

2. The oil-cooled electric drive end cover structure according to claim 1, characterized in that: The rear cover (1) has an installation groove for installing the filter (5); the end of the installation groove facing away from the motor housing (2) is open.

3. The oil-cooled electric drive end cover structure according to claim 1, characterized in that: The main oil passage (11) is located inside the rear end cover (1) near the outer circumference of the rear end cover (1).

4. The oil-cooled electric drive end cover structure according to claim 3, characterized in that: The main oil passage (11) includes a first oil passage section that connects to the filter (5) and a second oil passage section that connects to the oil cooler (6); the outlet end of the first oil passage section is connected to the inlet end of the second oil passage section to form a bent main oil passage (11).

5. The oil-cooled electric drive end cover structure according to claim 4, characterized in that: The axes of the first oil passage section and the second oil passage section are both perpendicular to the axis of the motor housing (2), and the intersection angle between the axis of the first oil passage section and the axis of the second oil passage section is no greater than 90°.

6. The oil-cooled electric drive end cover structure according to claim 1, characterized in that: The oil inlet, oil outlet, cooling water inlet and cooling water outlet of the oil cooler (6) are located at the four corners of the oil cooler (6), and the line connecting the oil inlet and oil outlet intersects the line connecting the cooling water inlet and cooling water outlet.

7. The oil-cooled electric drive end cover structure according to claim 6, characterized in that: The oil inlet is located above the oil outlet; the cooling water inlet is located below the cooling water outlet.

8. An electric drive housing, characterized in that: include: The oil-cooled electric drive end cap structure as described in any one of claims 1 to 7; The motor housing (2) is provided with a stator cooling oil passage (13) and a rotor cooling oil passage (14) respectively connected to the oil outlet of the oil cooler (6); and The reducer housing (3) is installed on the other axial end of the motor housing (2) relative to the rear end cover (1). The reducer housing (3) is provided with a differential cooling oil passage (15) that communicates with the oil outlet of the oil cooler (6).

9. An electric drive housing according to claim 8, characterized in that: It also includes an oil pump (4); the oil pump (4) is installed on the lower outer side of the motor housing (2), and the outlet end of the oil pump (4) is connected to the inlet end of the filter (5).

10. An electric drive assembly, characterized in that: The electric drive assembly includes the electric drive housing as described in claim 8 or 9.

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