Cooling system for motor

Abstract

The invention relates to a cooling system for a motor, a motor system, a control system and a speed reducer are arranged in a motor shell, the cooling system comprises an oil cooling system and a water cooling system, the oil cooling system is used for cooling the motor system and the speed reducer, and the water cooling system is used for cooling high-temperature oil generated in the control system and the oil cooling system. Auxiliary heat dissipation is carried out on the motor body; the oil cooling system comprises a motor oil cooling system and a speed reducer oil cooling system, the water cooling system comprises a controller water cooling system, an oil pan water cooling system and an exchanger water cooling system, and cooling liquid used by the controller water cooling system directly flows into the speed reducer oil cooling system for secondary cooling utilization. The two cooling systems are adopted to independently cool important parts, the cooling effect is improved, the two cooling systems interact with each other, and the water cooling system is adopted to cool the oil cooling system, so that the oil cooling system can form self-circulation in the shell, matched parts are greatly reduced, the overall size is reduced, and the reliability of a system assembly is improved.

Description

Technical Field

[0001] This invention relates to the technical field of motor systems, specifically to a cooling system for motors, and more particularly to a cooling system for motors in heavy-duty vehicles. Background Technology

[0002] In existing technologies, high-power electric heavy-duty vehicles mainly use low-speed motors for direct drive or in conjunction with a transmission. Because low-speed direct-drive motors are relatively large, if cooling is achieved solely through the casing using water or air, the temperature of the windings and core cannot be effectively conducted to the casing, resulting in limited heat dissipation. Therefore, in current large-diameter motors, the highest heat-generating point is typically at the armature winding, and the winding cannot directly dissipate heat through the casing. To address the aforementioned issues, some special stator structures exist in the prior art. For example, application number CN202410741511.2, entitled "A Motor Cooling Structure, Motor, and Vehicle," describes "a motor cooling structure, motor, and vehicle. The motor cooling structure includes: a stator core, the stator core having axially arranged stator slots, cooling channels, and a central hole; the stator slots having closed inner walls; the cooling channels being located at the stator yoke of the stator core; and cooling sleeves disposed at both ends of the stator core, the cooling sleeves having open annular cavities; the two ends of the windings extending outside the stator slots and disposed within the annular cavities; the annular cavities communicating with the cooling channels; and the annular cavities and cooling channels forming a coolant flow channel fluidly isolated from the central hole." However, this solution belongs to a stator-immersed oil-cooled motor. A very large flow rate and pressure of cooling oil are required to fully cover the stator core and windings, thereby achieving effective fluid wetting and cooling of all slots and windings. Insufficient flow rate and pressure will result in insufficient fluid in some tooth grooves (e.g., higher flow velocity near the oil outlet and lower flow velocity further away), leading to poor heat dissipation uniformity. Furthermore, this scheme involves large flow rates and pressures, resulting in a high power consumption for the cooling system. Therefore, the stator and rotor must be separated by an oil separator; otherwise, significant rotor oil churning resistance will form, leading to efficiency loss. However, using an oil separator to separate the stator and rotor places higher demands on the overall structure and airtightness, greatly increasing costs and posing a certain risk of failure. In summary, the existing technology has the following drawbacks: 1. Existing cooling methods often use water or air cooling for the casing, with heat dissipation achieved through the iron core contacting the casing. This results in an excessively long heat conduction chain, leading to significant heat accumulation in the core. Therefore, to prevent overheating due to heat buildup in the motor core, the motor needs to be made larger and heavier, with reduced electrical density to lower the overall winding temperature. This makes motor miniaturization difficult, which is highly unfavorable for vehicle-mounted installations.

[0003] 2. Immersion oil-cooled motors have a complex structure, low reliability, and are difficult to stabilize in fluid control. They also have high requirements for oil supply flow and power, resulting in high system costs.

[0004] 3. High-power oil-cooled motors have high heat dissipation requirements and often require multiple cooling systems. For example, the motor needs an independent oil-cooling or water-cooling system, the controller needs an independent water-cooling system, and the reducer also needs an independent oil-cooling or water-cooling system. These cooling systems also require external heat dissipation structures to cool the cooling oil or water. The system is too complex, with many external components, making operation inconvenient. This not only increases the size of the cooling system but also makes maintenance difficult.

[0005] 4. The integrated cooling structure of the controller and motor presents a problem of mutual interference. Motor controllers typically use water cooling solutions, which should not come into contact with oil or fumes. The motor's internal components cannot come into contact with cooling water, as this can cause insulation problems. Therefore, the motor and controller usually need to be installed separately, which inevitably increases the overall size and weight of the device. Furthermore, since they exist independently, external cables are required for connection. High-power motor cables often have large diameters, are heavy, and are difficult to bend, further increasing the overall weight and highlighting the issues of internal size and space layout.

[0006] Therefore, there is an urgent need in the market for a cooling system for motors that can reasonably control motor size, simplify system complexity and cost requirements, and provide good cooling effect and improve cooling efficiency. Summary of the Invention

[0007] The purpose of this invention is to provide a cooling system for an electric motor. Through structural improvements, an oil cooling system and a water cooling system are used for joint cooling. They are isolated from each other but interact with each other. The water cooling system cools the high-temperature oil generated by the oil cooling system and at the same time provides auxiliary heat dissipation for the motor. The oil cooling system achieves self-circulation inside the housing, resulting in high cooling efficiency and reducing the number of external pipelines and accessories, thereby reducing the overall size and weight.

[0008] To achieve the above objectives, the technical solution of the present invention is: a cooling system for an electric motor, comprising a motor housing, characterized in that: the motor housing houses a motor system, a control system cooperating with the motor system, and a reducer; the motor housing has a controller inlet and an outlet; the cooling system includes an oil cooling system and a water cooling system, the oil cooling system is used to cool the motor system and the reducer, and the water cooling system is used to cool the high-temperature oil generated in the control system and the oil cooling system, and to provide auxiliary heat dissipation for the motor body; the motor housing houses an oil pan for oil-water heat exchange and an external heat exchanger; the motor oil cooling system, after being cooled by the water cooling system, forms a closed self-circulation within the motor housing, while the water cooling system completes circulating cooling outside the motor housing through the inlet and outlet; the reducer oil cooling system, after being cooled by the heat exchange water cooling system, returns to the reducer, forming a closed self-circulation. The use of two cooling systems not only has a clear division of labor but also interacts with each other, improving the cooling effect and reducing the overall size of the system.

[0009] The oil cooling system includes a motor oil cooling system and a gearbox oil cooling system. The motor oil cooling system is located inside the motor. Oil is drawn from the motor by an oil pump, passes through a coarse filter, then a fine filter, and finally enters the motor from the bottom. It then flows through the motor's internal oil passages and is sprayed into the motor's interior to cool the core and windings. The cooled hot oil returns to the oil pan through the return port, forming an internal circulation. The gearbox oil cooling system is drawn from the gearbox by an oil pump, filtered, and then flows from the gearbox's outlet to the heat exchanger's oil cooling inlet. After being cooled by the heat exchanger, the oil flows out from the heat exchanger's oil cooling outlet and re-enters the gearbox's inlet, spraying it onto the parts inside the gearbox that require cooling, and finally returns to the gearbox housing, forming an internal circulation.

[0010] The water cooling system includes a controller water cooling system, an oil pan water cooling system, and an exchanger water cooling system. The controller water cooling channels are integrated within the motor housing and have inlet and outlet ports. These channels insulate the controller compartment from the motor housing, preventing heat generated by the motor from being transferred to the controller chip. Since the motor oil cooling system is bottom-in, top-out, the upper oil temperature and stator body temperature are higher. Therefore, the upper water channels also serve to assist in cooling the stator body. The oil pan water cooling system is located at the bottom of the oil pan and cools the hot oil after it has been cooled. The heat exchanger has both inlet and outlet ports for the oil to be cooled, as well as inlet and outlet ports for the active cooling water. The heat exchanger forms the reducer oil cooling system.

[0011] The outlet of the controller's water cooling system is connected to the inlet of the heat exchanger in the reducer's oil cooling system. This allows the coolant used in the controller's water cooling system to flow directly into the reducer's oil cooling system's heat exchanger for secondary cooling before being output through the heat exchanger's outlet. The high-temperature oil generated by the reducer's oil cooling system enters the inlet of the heat exchanger and exchanges heat with the heat exchanger's water cooling system before flowing back into the reducer. The high-temperature oil generated by the motor's oil cooling system enters the oil pan and exchanges heat independently with the oil pan's water cooling system. This secondary utilization of coolant in both the controller's water cooling system and the reducer's oil cooling system simplifies the internal piping design, resulting in a more compact system structure. It is also environmentally friendly, reduces cooling costs, and improves cooling efficiency.

[0012] Preferably, the outlet of the controller water cooling system is connected to the inlet of the external heat exchanger, and the outlet of the external heat exchanger is connected to the inlet of the oil pan water cooling system, allowing for tertiary cooling reuse of the cooling water. Alternatively, the inlets of the controller water cooling system and the oil pan water cooling system are connected to the inlets of the dual motor housings, allowing cold water to enter the controller water cooling system and the oil pan water cooling system respectively. The outlet of the controller water cooling system is connected to the inlet of the external heat exchanger for secondary cooling water reuse, and the outlet of the external heat exchanger is connected to the outlet of the oil pan water cooling system, and together they are connected in parallel to the outlet of the dual motor housings. Through these connection methods, the coolant can be reused two or even three times, maximizing the heat exchange utilization rate of the coolant, simplifying the connection piping, reducing cooling costs, improving efficiency, and achieving environmental protection and energy saving.

[0013] Furthermore, the oil pan is located at the bottom of the motor housing. The oil pan is divided into upper and lower layers. The upper layer is the oil storage area, and the lower layer is the oil pan water cooling system. The coolant in the oil pan water cooling system cools the high-temperature oil in the oil storage area. The oil inlet of the oil storage area is connected to the return oil channel of the motor oil cooling system, and the cooling oil naturally returns to the oil pan under gravity. By using the oil pan for heat exchange between the high-temperature oil and coolant, the heat exchange of the oil cooling system can be completed inside the motor, reducing the number of paths and external equipment, reducing system complexity, achieving good cooling effect, reducing cooling costs, and compressing system size.

[0014] Furthermore, the controller water cooling channel is integrated within the motor housing. The controller water cooling system includes an integrated controller water channel, an inlet, and an outlet. The water channel isolates the heat generated by the motor body from the controller compartment and the motor housing, preventing heat transfer to the control system and ensuring effective insulation between them. In addition, since the motor oil cooling system uses a bottom-in, top-out design, the upper oil temperature and stator body temperature are relatively high. Therefore, the integrated controller water channel located at the top also provides auxiliary heat dissipation for the stator body. The integrated controller water channel is arranged in a serpentine pattern, with a cooling top plate. Above the cooling top plate is the controller mounting compartment, allowing the controller water cooling system to directly cool the controller, resulting in significant cooling effects. The cooling top plate is equipped with a raised structure or a serpentine channel at the position corresponding to the water channel to increase the heat dissipation area and reduce the water resistance of the water channel. The serpentine water channel includes a longitudinal bending structure and a transverse bending structure. The longitudinal and transverse bending structures are arranged by several equally divided bending structures arranged in parallel, or by a large bending structure containing a small bending structure. This increases the length of the water channel through which the coolant flows and provides a more stable flow resistance throughout the entire process. At the same time, since the serpentine channel is directly arranged on the top plate, it can play a more direct role in heat dissipation and heat conduction, which can help improve the cooling effect.

[0015] Furthermore, the oil pan water cooling system features a zigzag water channel with guide vanes within it, creating a turbulence zone to disrupt eddies, reduce flow resistance, and balance flow velocity. Several guide vanes are arranged parallel to each other with gaps between them. The tops of the guide vanes have an inverted triangular structure to effectively turbulent the flow. The base plate of the oil pan water cooling system has heat dissipation reinforcing ribs to facilitate effective heat dissipation during vehicle operation. A weak connection point is formed at the junction of the base plate and the oil pan shell. If the oil pan is impacted or experiences significant changes in internal stress, this weak connection point will break first, ensuring that water from the oil pan water cooling system flows out through this point and does not enter the upper oil cooling area of ​​the oil pan, thus preventing damage to the oil cooling area and the upper motor system. This weak connection point is either a thin, integrally cast connection ring or a welded weak point.

[0016] Furthermore, the motor oil cooling system includes a dual oil pump motor that supplies cooling oil to the motor system. The bottom of the motor oil cooling system has several oil outlets, which are connected to the oil inlet of the oil storage area on the upper layer of the oil pan through a return oil passage. The oil storage area is equipped with a coarse filter, and the bottom of the coarse filter is equipped with a corresponding dual oil pump motor. This allows the cooling oil, after being cooled by the oil pan, to be drawn into the dual oil pump motor through the coarse filter, filtered by the fine oil filter, and then injected into the oil injection port of the motor system through the injection passage. This dissipates heat from the iron core and windings of the motor system, quickly reducing the heat in the iron core and windings at the highest temperature and improving the efficiency of the oil cooling system.

[0017] Furthermore, the oil storage area is equipped with an oil passage guide plate and an oil coarse filter. The oil coarse filter is located in the middle of the oil storage area. The oil passage guide plate around the oil coarse filter is arc-shaped or C-shaped, forming a semi-enclosed structure around the oil coarse filter. This ensures the storage of cooling oil around the oil coarse filter, so that the vehicle will not have insufficient cooling oil and will not be unable to cool down during uphill or downhill driving.

[0018] Furthermore, the reducer oil cooling system includes a circulating oil passage within the reducer body, a built-in oil pump that works in conjunction with the circulating oil passage, and an external heat exchanger connected to the circulating oil passage. The external heat exchanger contains a water cooling system for cooling the high-temperature oil generated by the reducer. The external heat exchanger has oil inlet and outlet ports, as well as water inlet and outlet ports. The water cooling system includes a coolant flow channel, with both ends connected to the water inlet and outlet ports of the external heat exchanger, respectively. By implementing the reducer oil cooling system, the reducer can be effectively cooled independently, and the combined effect with the water cooling system further enhances the cooling performance.

[0019] Compared with the prior art, the technical solution of the present invention not only improves the overall technical solution, but also includes many improvements in details. Specifically, it has the following beneficial effects: 1. The improved solution of the present invention includes an oil cooling system and a water cooling system. The oil cooling system is used to cool the motor system and the reducer, while the water cooling system is used to cool the high-temperature oil generated in the control system and the oil cooling system, and to provide auxiliary heat dissipation for the motor body. The motor housing is provided with an oil pan and an external heat exchanger for oil and water heat exchange. After being cooled by the water cooling system, the oil cooling system forms a closed self-circulation within the motor housing, while the water cooling system completes circulating cooling outside the motor housing through inlet and outlet water ports. The use of two cooling systems not only has a clear division of labor, but also works together to improve the cooling effect, reduce the overall size of the system, and facilitate the lightweight design and compact layout of the vehicle. 2. In the technical solution of the present invention, the oil cooling system includes a motor oil cooling system and a reducer oil cooling system, and the water cooling system includes a controller water cooling system, an oil pan water cooling system, and an exchanger water cooling system. The outlet of the controller water cooling system is connected to the inlet of the reducer oil cooling system, so that the coolant used in the controller water cooling system can directly flow into the reducer oil cooling system for secondary cooling and reuse. This simplifies the internal piping design of the system, makes the system structure more compact, reduces the overall size, and thus improves the reliability of the system assembly. Furthermore, the outlet of the reducer can be connected to the inlet of the oil pan, thereby forming a tertiary cooling reuse of the cooling water, further simplifying the piping design and reducing the overall size. 3. In the structure of the present invention, the high-temperature oil generated by the motor oil cooling system enters the oil pan and completes heat exchange with the oil pan water cooling system, eliminating the need for a separate external oil cooling device. This allows the oil cooling system to operate in a self-circulating manner within the casing, reducing the cooling cost of the oil cooling system and improving the cooling efficiency. 4. In the technical solution of the present invention, the controller water cooling system includes an integrated controller water channel. The integrated controller water channel is used to cool the control system and isolate the heat transfer between the motor system and the control system, ensuring the heat insulation effect between the two. At the same time, the integrated controller water channel covers the top of the motor in a semi-circular shape to assist in the heat dissipation of the motor. When the oil-cooled cooling oil in the motor cools the stator core and is ejected from the top, the integrated controller water channel can simultaneously perform the first layer of cooling on the ejected cooling oil. The integrated controller water channel is distributed in a serpentine pattern to increase the length of the water channel through which the coolant flows, which facilitates the improvement of the cooling effect. 5. In the structure of this invention, the oil pan water cooling system is provided with a zigzag water channel, and a water channel guide plate is arranged in the zigzag water channel to form a turbulence area, which is used to break the eddy current, reduce the flow resistance, stabilize the flow velocity, and improve the cooling effect. At the same time, the bottom plate of the oil pan water cooling system and the shell of the oil pan form a ring of weak connection points at the connection. Once the oil pan is impacted or the internal stress changes significantly, the weak connection points will break first, ensuring that the water of the oil pan water cooling system will flow out from the weak connection points and will not enter the upper oil cooling area of ​​the oil pan, causing damage to the oil cooling area and the upper motor system, thereby improving the safety factor of motor operation. Attached Figure Description

[0020] Figure 1 This is a cross-sectional structural diagram of an embodiment of the present invention.

[0021] Figure 2 This is a schematic diagram of the controller water cooling system and motor housing of the present invention.

[0022] Figure 3 This is a schematic diagram of the cooling top plate structure of the present invention.

[0023] Figure 4 This is another structural schematic diagram of the cooling top plate of the present invention.

[0024] Figure 5 This is a schematic diagram of the structure in an embodiment of the present invention.

[0025] Figure 6 This is another structural schematic diagram in an embodiment of the present invention.

[0026] Figure 7 This is a schematic diagram of the oil circuit self-circulation of the motor oil cooling system of the present invention.

[0027] Figure 8 This is a schematic diagram of the structure of the oil storage area in the oil pan of the present invention.

[0028] Figure 9 This is a schematic diagram of the water-cooled area structure of the oil pan of the present invention.

[0029] Figure label: 1. Reducer; 2. Motor system; 3. Control system; 4. Oil pan; 5. External heat exchanger; 6. Motor housing; 21. Front cover; 31 Integrated controller water channel, 32 Cooling top plate, 33 Controller water channel protrusion structure, 34 Longitudinal bending structure, 35 Lateral bending structure; 41 Oil storage area, 42 Oil pan water cooling system, 43 Water channel guide plate, 44 Heat dissipation reinforcing rib, 45 Oil storage area protrusion structure, 46 Oil channel guide plate, 47 Oil pan bottom plate, 48 Engine oil coarse filter device, 49 Zigzag water channel. 51 Heat exchanger oil inlet, 52 Heat exchanger oil outlet, 53 Heat exchanger water inlet, 54 Heat exchanger water outlet. Detailed Implementation

[0030] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. This example is applied to a dual-motor drive system, where the two motors drive in the same state; therefore, only a single-motor application is described. Similarly, applications with a single motor also fall within the scope of protection of the present invention.

[0031] This invention provides a cooling system for an electric motor, including an electric motor housing, see details below. Figure 1 The difference between it and the existing technology is that: the motor housing is equipped with a motor system 2, a control system 3 that works with the motor system, and a reducer 1. The motor housing is equipped with a water inlet and a water outlet for the entry and exit of cooling water.

[0032] Specifically, the cooling system includes an oil cooling system and a water cooling system. The oil cooling system cools the motor system and reducer, while the water cooling system cools the control system, auxiliary heat dissipation motor body, and the high-temperature oil generated in the oil cooling system. The motor housing contains an oil pan for oil-water heat exchange and an external heat exchanger. The oil cooling system, cooled by the water cooling system, forms a closed self-circulation within the motor housing. The water cooling system, through its inlet and outlet ports and connected in series with the heat exchanger and the oil pan's water cooling inlet and outlet, achieves circulating cooling both inside and outside the motor housing. The use of these two cooling systems not only clearly defines their functions, each cooling critical components individually, but also creates cooling tiers based on the different temperature tolerances of each component, improving cooling efficiency. Simultaneously, they interact; the water cooling system cools the oil cooling system, allowing the oil cooling system to form a self-circulation within the housing, significantly reducing the number of supporting components, compressing the overall cooling system volume, and improving the reliability of the system assembly.

[0033] In implementation, the significant differences in temperature sensitivity among the three systems can be leveraged by connecting two or three systems to achieve stepped cooling. Ultimately, the three systems are integrated to form a simplified system where only one or two water-cooling systems are available to the client, significantly reducing system complexity and the number of components. This improves cooling efficiency while reducing system costs. For example, if the controller's temperature threshold is 85℃, the water cooling temperature rise is within 10℃. The motor's temperature threshold is 160℃, with a water temperature rise of approximately 10℃. The reducer's temperature threshold is 120℃, with a water temperature rise of approximately 10℃. The controller and motor have higher requirements for safety and stability at actual temperatures, while the reducer has relatively lower sensitivity. Therefore, stepped cooling can be achieved by utilizing the differences in temperature sensitivity.

[0034] Example 1 This embodiment describes a cooling system for an electric motor, including a motor housing 6, a motor system 2, a control system 3 that works with the motor system, and a reducer 1 housed within the motor housing. The motor housing has an inlet and an outlet. The cooling system includes an oil cooling system and a water cooling system. The oil cooling system is used to cool the motor system and the reducer, while the water cooling system is used to cool the control system, the motor body for auxiliary heat dissipation, and the high-temperature oil generated in the oil cooling system. The motor housing has an oil pan 4 and an external heat exchanger 5 for heat exchange between the oil cooling and water cooling systems. After being cooled by the water cooling system, the oil cooling system forms a closed self-circulation within the motor housing, while the water cooling system completes circulating cooling outside the motor housing through the inlet and outlet. The use of two cooling systems not only clearly defines their functions and improves the individual cooling effect of each component, but also allows them to interact. The water cooling system further cools the oil cooling system, improving the utilization rate of the coolant, enhancing the cooling effect, and reducing the overall volume of the system.

[0035] The oil cooling system here includes a motor oil cooling system and a reducer oil cooling system. The water cooling system includes a controller water cooling system, an oil pan water cooling system, and an exchanger water cooling system. The outlet of the controller water cooling system is connected to the inlet of the external heat exchanger of the reducer oil cooling system, allowing the coolant used in the controller water cooling system to flow directly into the reducer oil cooling system for secondary cooling. The high-temperature oil generated by the reducer oil cooling system enters the external heat exchanger to exchange heat with the exchanger water cooling system. The high-temperature oil generated by the motor oil cooling system enters the oil pan and independently exchanges heat with the oil pan water cooling system. The cooling water is reused. Alternatively, the outlet of the external heat exchanger of the reducer oil cooling system can be connected to the inlet of the oil pan water cooling system, achieving three uses of the cooling water. This further simplifies the internal piping design, making the system structure more compact, environmentally friendly, reducing cooling costs, and improving cooling efficiency.

[0036] Specifically, the outlet of the controller water cooling system is connected to the inlet of the external heat exchanger of the reducer oil cooling system, and the outlet of the external heat exchanger is connected to the inlet of the oil pan water cooling system. Cooling water is finally output from the outlet of the oil pan water cooling system. Through the above connection method, the coolant can be reused three times, so that the heat exchange utilization rate of the coolant is maximized, cooling costs are reduced, the effect is improved, and environmental protection and energy saving are achieved.

[0037] Specifically, the coolant in the controller's water-cooling system can be a mixture of ethylene glycol and water. This mixture has a high specific heat capacity, effectively controlling the chip temperature within its operating range (typically, the chip's detection operating temperature is below 85°C). The outlet water temperature rise of the controller's water-cooling system is within 10°C (in this embodiment, the inlet water temperature is controlled at 45-50°C, and the outlet temperature does not exceed 60°C). The outlet of the controller's water-cooling system is connected to the inlet of the external heat exchanger of the reducer 1. The cooling water from the outlet of the controller's water-cooling system enters the external heat exchanger, further cooling the reducer's cooling oil and dissipating heat from the reducer's output cooling oil. The reducer's cooling oil can withstand temperatures up to 120°C, so using 60°C water can effectively lower the cooling oil temperature to below 80°C, ensuring stable operation of the reducer (at this point, the water temperature rise is also within 10°C, i.e., the outlet temperature does not exceed 70°C). Furthermore, the outlet of the external heat exchanger is connected to the inlet of the oil pan to cool the hot oil in the oil pan. The hot oil in the oil pan then circulates to cool the motor body internally. Since the motor in this example can withstand temperatures up to 180℃, this can be further increased to 220℃ after improvements to the motor's temperature resistance rating. Therefore, the cooled water can be further used to cool the oil in the motor body. This is not only environmentally friendly but also simplifies the cooling system. Finally, the cooling water enters the vehicle's radiator from the outlet of the oil pan water-cooling system, achieving thermal balance between the controller water cooling, reducer, and motor oil pan oil cooling. Both the reducer and motor body oil cooling are internally sealed, eliminating the need for routine maintenance and reducing operating costs.

[0038] The water cooling system includes a controller water cooling system, an oil pan water cooling system, and an exchanger water cooling system. The controller water cooling system includes an integrated controller water channel 31. This integrated controller water channel is used to cool the control system and isolate the motor system from the control system, ensuring effective heat insulation between them. See [link to relevant documentation]. Figure 2 .

[0039] The oil pan water cooling system features a zigzag water channel, see [link / reference]. Figure 9 The zigzag water channel is equipped with water channel guide plates 43, forming a turbulence zone to disrupt eddies, reduce flow resistance, and stabilize flow velocity, thereby improving heat dissipation efficiency. The base plate of the oil pan water cooling system is equipped with heat dissipation reinforcing ribs to facilitate effective heat dissipation during vehicle operation.

[0040] The external heat exchanger 5 is equipped with a water cooling system, see [link / reference]. Figure 6It is used to cool down the high-temperature oil generated by the reducer. The external heat exchanger is equipped with a heat exchanger oil inlet 51, a heat exchanger oil outlet 52, a heat exchanger water inlet 53 and a heat exchanger water outlet 54. The heat exchanger water cooling system includes a coolant flow channel, and the two ends of the coolant flow channel are connected to the inlet and outlet of the external heat exchanger, respectively.

[0041] The oil cooling system includes a motor oil cooling system and a gearbox oil cooling system. The motor oil cooling system includes a dual-oil-pump motor that supplies cooling oil to the motor system. A schematic diagram of the oil circulation circuit for the motor oil cooling system can be found here. Figure 7 The bottom of the motor oil cooling system has several oil outlets, which are connected to the oil inlet of the oil storage area on the upper layer of the oil pan through the return oil passage. The oil storage area is equipped with a coarse filter, and the bottom of the coarse filter is equipped with a corresponding dual oil pump motor. The cooling oil after being cooled by the oil pan is drawn into the dual oil pump motor through the coarse filter, then filtered by the fine oil filter, and finally injected into the oil injection port of the motor system through the injection passage to dissipate heat from the iron core and windings of the motor system. This can quickly reduce the heat of the iron core and windings at the highest temperature and improve the efficiency of the oil cooling system.

[0042] The reducer oil cooling system includes a circulating oil passage within the reducer body, a built-in oil pump that works in conjunction with the circulating oil passage, and an external heat exchanger connected to the circulating oil passage. The external heat exchanger contains a water cooling system for cooling the high-temperature oil generated by the reducer. The external heat exchanger has oil inlet and outlet ports, as well as water inlet and outlet ports. The water cooling system includes cooling water channels, with both ends connected to the inlet and outlet ports of the external heat exchanger, respectively. By implementing the reducer oil cooling system, the reducer can be effectively cooled independently; combined with the water cooling system, the cooling effect is further enhanced.

[0043] The oil pan is located at the bottom of the motor housing. The oil pan is divided into upper and lower layers. The upper layer is the oil storage area 41, and the lower layer is the oil pan water cooling system 42. The coolant in the oil pan water cooling system cools the high-temperature oil in the oil storage area. The oil inlet of the oil storage area is connected to the return oil passage of the motor oil cooling system. Using the oil pan for heat exchange between the high-temperature oil and coolant allows the heat exchange of the oil cooling system to be completed inside the motor, reducing the number of paths and external equipment, lowering system complexity, achieving good cooling effect, reducing cooling costs, and compressing system size.

[0044] Example 2 This embodiment describes a cooling system for an electric motor, including a motor housing 6, a motor system 2, a control system 3 that works with the motor system, and a reducer 1 inside the motor housing. The motor housing has a water inlet and a water outlet. The cooling system includes an oil cooling system and a water cooling system. The oil cooling system is used to cool the motor system and the reducer, while the water cooling system is used to cool the control system, the motor body, and the high-temperature oil generated in the oil cooling system. The motor housing has an oil pan 4 for oil-water heat exchange and an external heat exchanger 5. After being cooled by the water cooling system, the oil cooling system forms a closed self-circulation within the motor housing, while the water cooling system completes circulating cooling outside the motor housing through the water inlet and outlet. The use of two cooling systems not only has a clear division of labor but also interacts with each other, improving the cooling effect and reducing the overall size of the system.

[0045] The oil cooling system includes an oil cooling system for the motor and an oil cooling system for the reducer. The water cooling system includes a water cooling system for the controller, an oil pan, and an exchanger. The outlet of the controller water cooling system is connected to the inlet of the reducer oil cooling system, allowing the coolant used in the controller water cooling system to flow directly into the reducer oil cooling system for secondary cooling. The high-temperature oil generated by the reducer oil cooling system enters an external heat exchanger and exchanges heat with the exchanger water cooling system before returning to the reducer, achieving internal circulation. The motor oil pan water cooling system has its own independent cooling water path to protect the motor temperature and ensure safety. The high-temperature oil generated by the motor oil cooling system enters the oil pan and exchanges heat with the oil pan water cooling system. Finally, the water cooling outlets of the external heat exchanger and the motor oil pan converge and are output to the vehicle radiator for cooling. This simplifies the internal piping design, making the system structure more compact, while also prioritizing the thermal safety of the motor itself. It is environmentally friendly, reduces cooling costs, and improves cooling efficiency.

[0046] Specifically, see Figure 2 , Figure 3 The water cooling system in this implementation includes a controller water cooling system, an oil pan water cooling system, and an exchanger water cooling system. The controller water cooling system includes an integrated controller water channel 31. This integrated controller water channel cools the control system and isolates the motor system from the control system, ensuring effective heat insulation between them. The integrated controller water channel is serpentine in shape, with a cooling top plate 32 at the top. Above the cooling top plate is a controller mounting compartment, allowing the controller water cooling system to directly cool the controller, resulting in significant cooling. The integrated controller water channel uses a method of water intake from both sides of the motor controller chip, ultimately converging and exiting from the center. This ensures that both water channels can effectively cool the motor controller chip, avoiding the problem of heat dissipation performance degradation caused by the gradual increase in cooling water temperature along the path of the water channel.

[0047] The cooling top plate and the corresponding water channels are equipped with densely packed protruding structures or serpentine channels 33 to increase the heat dissipation area and reduce water resistance. These structures are integrated with the cooling top plate to improve heat conduction efficiency and prevent reduced heat conduction due to incomplete contact. The serpentine water channels include longitudinal bending structures 34 and transverse bending structures 35. The longitudinal and transverse bending structures are arranged in parallel with several equally divided bending structures. Generally, 2-5 parallel equally divided bending structures can be arranged and connected end-to-end, or a large bending structure can be nested within a smaller bending structure to increase the length of the water channels through which the coolant flows, thus improving the cooling effect. The serpentine water channels can be arranged by connecting transverse bending structures to longitudinal bending structures, or by connecting transverse bending structures to longitudinal bending structures and then connecting transverse bending structures, so that the water channels are filled as much as possible, increasing the water channel length.

[0048] Further, see Figure 9 The oil pan water cooling system 42 forms a zigzag water channel 49 by setting water channel baffles. The zigzag water channel is arranged along the width direction of the oil pan. Water channel guide plates 43 are arranged in the zigzag water channel to form a turbulence area, which is used to break eddies, reduce flow resistance, and at the same time play a role in uniform flow velocity. Several water channel guide plates are arranged in parallel in sequence with gaps between them (the gap value is 0.5-3mm). The top of the water channel guide plates has an inverted triangular structure to form effective turbulence, break the eddies caused by high-speed water flow, so that the coolant can adhere to the top plate of the oil pan water cooling system for effective flow, uniform flow velocity, and improved cooling effect of the coolant.

[0049] The base plate 47 of the oil pan water cooling system is equipped with heat dissipation reinforcing ribs 44. These ribs are arranged along the vehicle's driving direction, utilizing the airflow generated during vehicle movement to assist in heat dissipation of the oil pan water channels, thus improving heat dissipation efficiency. Simultaneously, they increase the rigidity and strength of the base plate, reducing the risk of deformation and damage when the water cooling channel pressure changes. A weak connection point is formed at the joint between the base plate of the oil pan water cooling system and the oil pan shell. If the oil pan is impacted or experiences a significant change in internal stress, this weak connection point will break first, ensuring that the water in the oil pan water cooling system flows out through this weak connection point and does not enter the upper oil cooling area of ​​the oil pan, thus preventing damage to the oil cooling area and the upper motor system. The weak connection point is either a weakening groove formed by integral casting or a welding weak point formed during the welding process. In this case, the thin connecting ring refers to a weld thickness at this point that is 2 / 3 to 1 / 2 of the weld thickness in other areas. This ensures that in the event of a large impact or stress change, this point becomes the primary breakage point, facilitating coolant outflow.

[0050] The external heat exchanger is equipped with a water cooling system for cooling the high-temperature oil generated by the reducer. The external heat exchanger has oil inlet and outlet and water inlet and outlet. The water cooling system includes a coolant channel, and the two ends of the coolant channel are connected to the water inlet and outlet of the external heat exchanger, respectively.

[0051] Example 3 The motor housing described in this embodiment is provided with a motor system 2, a control system 3 that cooperates with the motor system, and a reducer 1. The motor housing is provided with a water inlet and a water outlet. The cooling system includes an oil cooling system and a water cooling system. The oil cooling system is used to cool the motor system and the reducer, and the water cooling system is used to cool the high-temperature oil generated in the control system and the oil cooling system. The motor housing is provided with an oil pan 4 for oil and water heat exchange and an external heat exchanger 5. After being cooled by the water cooling system, the oil cooling system forms a closed self-circulation in the motor housing. The water cooling system completes the circulating cooling outside the motor housing through the water inlet and outlet. The oil cooling system includes a motor oil cooling system and a reducer oil cooling system. The water cooling system includes a controller water cooling system, an oil pan water cooling system, and an exchanger water cooling system. The outlet of the controller water cooling system is connected to the inlet of the reducer oil cooling system, so that the coolant used by the controller water cooling system can directly flow into the external heat exchanger water cooling inlet of the reducer oil cooling system for secondary cooling. The high-temperature oil generated by the reducer oil cooling system enters the oil inlet of the external heat exchanger and completes heat exchange with the exchanger water cooling system. The high-temperature oil generated by the motor oil cooling system enters the oil pan and completes heat exchange with the oil pan water cooling system.

[0052] Furthermore, the motor oil cooling system includes a dual-pump motor that supplies cooling oil to the motor system. The bottom of the system has several oil outlets, which are connected to the inlet of the oil reservoir area on the upper layer of the oil pan via return oil channels. The oil reservoir area is equipped with an oil coarse filter 48, and a corresponding dual-pump motor is located at the bottom of the coarse filter. This allows the cooling oil, cooled by the oil pan, to be drawn into the dual-pump motor through the coarse filter, filtered by the fine oil filter, and then injected into the motor system's injection port through the injection channel. This dissipates heat from the motor's core and windings, quickly reducing the heat at the highest points and improving the efficiency of the oil cooling system. Because the cooling oil penetrates deep into the motor for direct heat dissipation, the overall temperature of the core and windings can be effectively and promptly reduced, eliminating concerns about overheating due to heat accumulation. This facilitates miniaturization and reduces the overall size of the motor. Specifically, the dual oil pump motor sprays cooling oil onto the iron core and windings of the motor system. The cooling oil then flows down naturally under gravity and enters the oil pan through the three oil outlets of the motor system. This process is repeated, forming a self-circulation within the pan.

[0053] Further, see Figure 5 , Figure 8The oil storage area 41 is equipped with an oil passage guide plate 46 and an oil coarse filter device 48. The oil coarse filter device 48 is located in the middle of the oil storage area. Since it is desired that the cooling oil flows as far as possible in the oil pan to facilitate sufficient heat exchange with the water-cooled area of ​​the lower oil pan, it is necessary to increase the contact time and area between the cooling oil and the bottom surface of the oil storage area. During operation, the cooling oil is guided to both sides by the oil baffle plate and enters the oil pan. Under the guidance of the oil passage guide plate 46 in the upper oil storage area of ​​the oil pan, the cooling oil passes through the oil coarse filter device and is finally sucked into the oil pump motor. The oil passage guide plates 46 surrounding the oil coarse filter are arc-shaped or C-shaped, forming a semi-enclosed structure around the oil coarse filter. The so-called semi-enclosed structure means that the oil coarse filter is surrounded by 2 / 5 to 3 / 4 of its perimeter to ensure the storage of cooling oil around the oil coarse filter. This prevents insufficient cooling oil and the inability to cool the vehicle during uphill or downhill driving. The remaining oil passage guide plates are straight and arranged around the oil storage area. The straight oil passage guide plates have bends in the middle or at both ends to better guide the cooling oil and enhance the cooling effect.

[0054] Numerous raised oil reservoir structures 45 are added to the bottom of the oil reservoir area to increase the heat dissipation area. Since the cooling oil flows naturally and the oil pan is unlikely to form a fixed effective flow channel, guide ribs are installed, along with numerous regularly spaced raised ribs, effectively creating a series of directional guide ribs. This increases the heat dissipation area while minimizing flow resistance, achieving a more uniform flow velocity to ensure effective flow and oil absorption, while maximizing the effective heat conduction area for fluid contact. The height of the raised oil reservoir structures is less than the height of the oil channel guide plate.

[0055] Furthermore, the reducer oil cooling system includes a circulating oil passage within the reducer body, a built-in oil pump that works in conjunction with the circulating oil passage, and an external heat exchanger connected to the circulating oil passage. The external heat exchanger contains a water cooling system for cooling the high-temperature oil generated by the reducer. The external heat exchanger has oil inlet and outlet ports, as well as water inlet and outlet ports. The water cooling system includes coolant channels, with both ends connected to the water inlet and outlet ports of the external heat exchanger, respectively. By implementing an oil cooling system, the reducer can be effectively cooled independently; combined with the water cooling system, the cooling effect is further enhanced.

[0056] The aforementioned oil cooling system can directly cool the iron core and windings of the motor system independently. Without increasing the system size, it reduces the risk of heat accumulation, ensuring effective heat conduction to the hottest windings and eliminating concerns about overheating. This facilitates smaller motor designs and effectively reduces motor size. Simultaneously, a water cooling system is used to further cool the oil cooling system, creating a self-circulating system within the motor power system. This eliminates the need for external heat dissipation, simplifies the system structure, facilitates later maintenance and upkeep, and reduces production and installation costs.

[0057] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A cooling system for an electric motor, comprising an electric motor housing, characterized in that: The motor housing houses the motor system, a control system that works in conjunction with the motor system, and a reducer. The motor housing has an inlet and an outlet for water. The cooling system includes an oil cooling system and a water cooling system. The oil cooling system cools the motor system and reducer, while the water cooling system cools the high-temperature oil generated in the control system and the oil cooling system. The motor housing contains an oil pan for oil-water heat exchange and an external heat exchanger. The oil cooling system, after being cooled by the water cooling system, forms a closed self-circulating system within the motor housing. The water cooling system completes its circulating cooling outside the motor housing through the inlet and outlet. The oil cooling system includes a motor oil cooling system and a reducer oil cooling system, while the water cooling system includes a controller water cooling system. The system includes a cooling system, an oil pan water cooling system, and an exchanger water cooling system. The outlet of the controller water cooling system is connected to the inlet of the external heat exchanger of the reducer oil cooling system, allowing the cooling water from the controller water cooling system to flow directly into the reducer oil cooling system for secondary cooling. The high-temperature oil generated by the reducer oil cooling system enters the external heat exchanger to exchange heat with the exchanger water cooling system, and the high-temperature oil generated by the motor oil cooling system enters the oil pan to exchange heat with the oil pan water cooling system. The reducer oil cooling system includes a circulating oil passage located inside the reducer body, a built-in oil pump that works with the circulating oil passage, and an external heat exchanger connected to the circulating oil passage.

2. A cooling system for an electric motor according to claim 1, characterized in that: The outlet of the controller water cooling system is connected to the inlet of the external heat exchanger, and the outlet of the external heat exchanger is connected to the inlet of the oil pan water cooling system, allowing for tertiary cooling of the cooling water. Alternatively, the inlets of the controller water cooling system and the oil pan water cooling system are connected to the inlets of the dual motor housings, allowing cold water to enter the controller water cooling system and the oil pan water cooling system respectively. The outlet of the controller water cooling system is connected to the inlet of the external heat exchanger, enabling secondary cooling water utilization. The outlet of the external heat exchanger is connected to the outlet of the oil pan water cooling system, and together they are connected in parallel to the outlet of the dual motor housings.

3. A cooling system for an electric motor according to claim 1, characterized in that: The oil pan is located at the bottom of the motor housing. The oil pan is divided into upper and lower layers. The upper layer of the oil pan is the oil storage area, and the lower layer is the oil pan water cooling system. The coolant of the oil pan water cooling system cools the high-temperature oil in the oil storage area. The oil inlet of the oil storage area is connected to the oil return channel of the motor oil cooling system.

4. A cooling system for an electric motor according to claim 1, characterized in that: The controller water cooling system includes an integrated controller water channel, which is used to cool the control system and isolate the motor system from the control system. The integrated controller water channel is distributed in a serpentine pattern and has a cooling top plate. Above the cooling top plate is a controller mounting compartment.

5. A cooling system for an electric motor according to claim 1, characterized in that: The oil pan water cooling system is equipped with zigzag water channels, and water channel guide plates are arranged in the zigzag water channels to form a turbulence area, which is used to break the eddy current, reduce the flow resistance, and uniform the flow velocity. Several water channel guide plates are arranged in parallel in sequence with gaps between them, and the top of the water channel guide plates has an inverted triangular structure.

6. A cooling system for an electric motor according to claim 4, characterized in that: The cooling top plate and the corresponding position of the water channel are provided with a protruding structure or a serpentine guide channel to increase the heat dissipation area and reduce the water resistance of the water channel, and to uniformly distribute the flow rate. The serpentine water channel includes a longitudinal bending structure and a transverse bending structure. The longitudinal and transverse bending structures are arranged by several equally divided bending structures arranged in parallel, or by a large bending structure containing a small bending structure.

7. A cooling system for an electric motor according to claim 1, characterized in that: The motor oil cooling system includes a dual oil pump motor that supplies cooling oil to the motor system. The bottom of the motor oil cooling system has several oil outlets, which are connected to the oil inlet of the oil storage area on the upper layer of the oil pan through a return oil passage. The oil storage area is equipped with a coarse filter, and the bottom of the coarse filter is equipped with a corresponding dual oil pump motor. This allows the cooling oil, after being cooled by the oil pan, to be drawn into the dual oil pump motor through the coarse filter, filtered by the fine oil filter, and then injected into the oil injection port of the motor system through the injection passage to dissipate heat from the iron core and windings of the motor system.

8. A cooling system for an electric motor according to claim 7, characterized in that: The oil storage area is equipped with an oil passage guide plate and an oil coarse filter. The oil coarse filter is located in the middle of the oil storage area. The oil passage guide plate around the oil coarse filter is arc-shaped or C-shaped, forming a semi-enclosed structure for the oil coarse filter to ensure the storage amount of cooling oil around the oil coarse filter.

9. A cooling system for an electric motor according to claim 1, characterized in that: The base plate of the oil pan water cooling system is equipped with heat dissipation reinforcing ribs. The base plate of the oil pan water cooling system and the shell of the oil pan form a ring of weak connection points at the connection point to ensure that the water of the oil pan water cooling system will not enter the oil cooling area of ​​the upper layer of the oil pan. The weak connection points are thin connection rings formed by integral casting or welding weak points.

10. A cooling system for an electric motor according to claim 1, characterized in that: The external heat exchanger is equipped with a heat exchanger water cooling system to cool down the high-temperature oil generated by the reducer. The external heat exchanger is equipped with oil inlet and outlet and water inlet and outlet. The heat exchanger water cooling system includes a cooling water channel, and the two ends of the cooling water channel are connected to the water inlet and outlet of the external heat exchanger, respectively.

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