An oil-cooled electric machine
By using an oil-cooled motor structure, the cooling oil forms a circulation path inside the motor, solving the problem of insufficient heat dissipation of air-cooled and water-cooled methods, and achieving efficient motor heat dissipation and stable operating performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- NIDEC MOTION CONTROL TECH (GUANGDONG) CO LTD
- Filing Date
- 2025-06-11
- Publication Date
- 2026-05-29
AI Technical Summary
Existing motor cooling technologies, such as air cooling and water cooling, suffer from complex structures, large space requirements, or high thermal resistance, and cannot effectively meet the heat dissipation needs of high-speed motors.
The motor adopts an oil-cooled structure, including components such as the frame, end cover, stator, oil baffle ring, and rotor. It utilizes the cooling oil to form a circulation path inside the motor, and prevents oil leakage through the labyrinth seal groove, thereby achieving effective circulation and lubrication of the cooling oil and enhancing the heat dissipation effect.
It improves the heat dissipation efficiency of the motor, reduces the motor temperature, extends the service life, and improves the rotor's operating stability and electromagnetic performance.
Smart Images
Figure CN224305586U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of motor cooling technology, and in particular to an oil-cooled motor. Background Technology
[0002] As one of the core components of new energy vehicles, the performance of automotive drive motors plays a crucial role in the overall vehicle's power, economy, and reliability. To meet the ever-increasing power demands of automobiles and the design requirements for lightweight and miniaturized vehicles, the performance requirements for automotive drive motors are becoming increasingly stringent. Among these requirements, achieving high power density and high torque density necessitates higher motor speeds.
[0003] However, during high-speed operation, electric motors generate a significant amount of heat due to internal electromagnetic losses and mechanical friction. Therefore, effectively dissipating heat from high-speed automotive drive motors has become one of the key issues hindering the further development of electric motors.
[0004] Common heat dissipation technologies mainly include air cooling and water cooling. Air cooling technology uses a fan to blow air over the motor surface, using the airflow to remove heat. However, air cooling systems require a series of components such as fans and air ducts, making their structure relatively complex and requiring a large space for installation, thus limiting their applicability. Water cooling technology involves creating dedicated water channels in the motor housing, using the flow of coolant in these channels to absorb and remove the heat generated by the motor, thereby reducing its temperature. However, because the coolant has a long flow path within the motor housing, there is thermal resistance during heat transfer, resulting in lower heat transfer efficiency and failing to fully meet the motor's heat dissipation requirements. Utility Model Content
[0005] To improve the heat dissipation efficiency of the motor, this application provides an oil-cooled motor.
[0006] To achieve the above objectives, this application adopts the following technical solution:
[0007] An oil-cooled motor includes a frame having an inner cavity; end covers, each including a front end cover and a rear end cover, which are respectively connected to both ends of the frame; a stator, comprising a stator core fitted into the inner cavity of the frame, with windings at both ends of the stator core; oil baffles fitted into both ends of the inner cavity of the frame and axially limited by the frame; and a rotor, comprising a shaft, a rotor core, rotor end plates, and steel sleeves, wherein the rotor core is fitted onto the shaft, and the rotor end plates are located at both ends of the rotor core and fitted onto the shaft. Above, the steel sleeve is disposed at both ends of the rotor end plate and sleeved on the rotating shaft; the base is provided with an oil inlet and a base oil hole, and a local oil cavity is formed between the base and the oil baffle ring, the oil inlet is connected to the local oil cavity, and the local oil cavity is connected to the base oil hole; the outer surface of the stator core is axially distributed with through oil grooves, and the through oil grooves are connected to the local oil cavity; the rear end cover is provided with a rear end cover oil passage, and the rear end cover oil passage is aligned with the base oil hole; the rotor is provided with an internal circulation oil passage, and the internal circulation oil passage passes through the rotating shaft, rotor end plate, rotor core and steel sleeve in sequence.
[0008] By employing the aforementioned device, the frame, as the fundamental component of the oil-cooled motor, supports key components such as the stator core, while the front and rear covers protect and secure the internal components. Oil baffles, fitted at both ends of the frame and axially limited by the frame, effectively prevent cooling oil leakage. During motor operation, the oil baffles prevent cooling oil from overflowing from the gap between the frame and the end covers, ensuring continuous and effective cooling. Compared to air or water cooling, the cooling oil absorbs more heat, quickly dissipating heat generated within the motor, effectively reducing its temperature and extending its lifespan. The cooling oil also lubricates various components. Furthermore, the rotor end plates axially limit the rotor core, preventing axial movement during operation and ensuring stable electromagnetic performance. The steel sleeves further enhance the structural strength of the rotor ends, enabling them to withstand centrifugal and electromagnetic forces generated during motor operation, further improving rotor stability.
[0009] Preferably, the oil baffle ring includes a baffle and a ring body, and the two ends of the base are also provided with limiting steps. The baffle is positioned by the limiting steps. A groove is opened on one side of the extended ring body, and a circular boss is provided on one side of the rotor end plate. The circular boss, the ring body and the groove are combined to form a non-contact labyrinth sealing groove.
[0010] By employing the above-mentioned device, the non-contact labyrinth seal groove is used to act as an oil seal when the rotor rotates, preventing oil leakage.
[0011] Preferably, the bottom of the machine base is provided with an oil drain port and an oil collection tank, the oil drain port being located at both ends of the machine base and connected to the oil collection tank.
[0012] By using the above-mentioned device, the oil drain port and oil collection tank can effectively collect and discharge the cooling oil inside the motor, avoiding the accumulation of cooling oil inside the motor that would cause the temperature to rise, thereby improving the motor's heat dissipation performance and reliability.
[0013] Preferably, the rear end cover is further provided with a rear bearing chamber, a rear oil drain groove and a rear end cover oil cavity. The rear end cover oil cavity is connected to the rear end cover oil passage. An oil inlet component is provided between the rear bearing chamber and the rear end cover oil cavity. The oil inlet component is connected to the rotating shaft. A bearing is installed in the rear bearing chamber. The rear oil drain groove is connected to the oil collection groove through the oil drain port.
[0014] By employing the aforementioned device, the rear end cover oil chamber is connected to the rear end cover oil passage, allowing the coolant to flow smoothly and enhancing heat dissipation. The oil inlet component between the rear bearing chamber and the rear end cover oil chamber is connected to the rotor shaft, enabling the coolant to flow directly from the rear end cover oil chamber through the inlet component into the rotor's internal circulation oil passage. This further optimizes the coolant flow path, improves cooling efficiency, and reduces heat accumulation. The rear drain oil tank is connected to the oil collection tank via the drain port, achieving effective recovery and recycling of the coolant, ensuring the system's continuous and stable heat dissipation performance.
[0015] Preferably, the front end cover is provided with a front bearing chamber and a front oil drain groove, a bearing is installed in the front bearing chamber, and the front oil drain groove is connected to the oil collection groove through the oil drain port.
[0016] By adopting the above-mentioned device, the bearing is installed in the front bearing chamber. After the oil is thrown out from the rotor to lubricate and cool the bearing, it is discharged from the front oil drain groove and collected in the oil collection groove at the bottom of the machine base, thus realizing the effective recovery and circulation of cooling oil.
[0017] Preferably, the internal circulation oil passage is connected to both the front bearing chamber and the rear bearing chamber.
[0018] By employing the above-mentioned device, cooling oil is thrown out from the rotor's internal circulation oil passage to lubricate and cool the bearings in the front and rear bearing chambers.
[0019] Preferably, the oil collection tank is provided with a cover plate, and the cover plate is provided with an oil outlet. The oil outlet is used to connect an external oil pump and an oil cooler and then connect to the oil inlet to form an oil circulation circuit.
[0020] By using the above-mentioned device, after the oil in the oil collection tank is discharged from the oil outlet, it is cooled by the oil cooler, and the oil pump then re-inputs the cooled oil into the motor through the oil inlet to form an oil circulation, which further improves the heat dissipation effect.
[0021] Preferably, an oil seal is provided between the oil inlet component and the rotating shaft.
[0022] By using the above-mentioned device, the oil seal can effectively prevent cooling oil from leaking from the gap between the oil inlet component and the rotating shaft.
[0023] This application has the following beneficial effects:
[0024] 1. In this application, the frame, as the basic component of the oil-cooled motor, supports key components such as the stator core. The front and rear covers protect and secure the internal components of the motor. Oil baffles are fitted at both ends of the frame and axially limited by the frame, effectively preventing cooling oil leakage. During motor operation, the oil baffles prevent cooling oil from overflowing from the gap between the frame and the end covers, allowing the cooling oil to continuously and effectively perform its cooling function. Compared to air or water cooling, the cooling oil absorbs more heat, quickly removing the heat generated inside the motor, effectively reducing the motor temperature, extending its service life, and providing lubrication for various components. Furthermore, the rotor end plates axially limit the rotor core, preventing axial movement during operation and ensuring stable electromagnetic performance of the motor. The steel sleeves further enhance the structural strength of the rotor ends, enabling them to withstand centrifugal and electromagnetic forces generated during motor operation, further improving rotor operational stability.
[0025] 2. In this application, the rear end cover oil cavity is connected to the rear end cover oil passage, allowing the coolant to flow smoothly and enhancing heat dissipation. The oil inlet component between the rear bearing chamber and the rear end cover oil cavity is connected to the rotor shaft, allowing the coolant to flow directly from the rear end cover oil cavity through the inlet component into the rotor's internal circulation oil passage. This further optimizes the coolant flow path, improves cooling efficiency, and reduces heat accumulation. The rear drain oil trough is connected to the oil collection trough via the drain port, enabling effective recovery and recycling of the coolant, ensuring continuous and stable heat dissipation performance of the system. Attached Figure Description
[0026] Figure 1 This is an exploded view of the oil-cooled motor according to an embodiment of this utility model;
[0027] Figure 2 This is a cross-sectional view of the oil-cooled motor according to an embodiment of the present invention;
[0028] Figure 3 yes Figure 2 Enlarged view of section A;
[0029] Figure 4 This is a schematic diagram of the oil-cooled motor base according to an embodiment of the present invention;
[0030] Figure 5 This is a schematic diagram of the rotor of an oil-cooled motor according to an embodiment of this utility model.
[0031] Explanation of reference numerals in the attached figures:
[0032] 1. Frame; 11. Oil inlet; 12. Frame oil hole; 13. Limiting step; 14. Oil outlet; 15. Oil collection groove; 16. Cover plate; 161. Oil outlet; 2. End cover; 21. Front end cover; 211. Front bearing chamber; 212. Front drain groove; 22. Rear end cover; 221. Rear end cover oil passage; 222. Rear bearing chamber; 223. Rear drain groove; 224. Rear end cover oil cavity; 3. Stator; 31. Stator core; 311. Through oil groove; 32. Winding; 4. Oil retaining ring; 41. Baffle; 42. Ring body; 421. Groove; 5. Rotor; 51. Shaft; 52. Rotor core; 53. Rotor end plate; 531. Circular boss; 54. Steel sleeve; 55. Internal circulation oil passage; 6. Oil inlet component; 7. Bearing; 8. Oil seal. Detailed Implementation
[0033] The following is in conjunction with the appendix Figure 1-5 This application will be described in further detail.
[0034] An oil-cooled motor, such as Figure 1 and 5 As shown, the system includes a base 1, end covers 2, a stator 3, an oil baffle ring 4, and a rotor 5. The base 1 has an inner cavity, while the end cover 2 includes a front cover 21 and a rear cover 22, located at opposite ends of the base 1 and fixed to it with bolts. The end cover 2 is sealed to the base 1 by a sealing ring. The stator 3 includes a stator core 31 fitted into the inner cavity of the base 1, with windings 32 mounted at both ends of the stator core 31. The oil baffle ring 4 is fitted at both ends of the inner cavity of the base 1 and is axially limited by the base 1. The rotor 5 includes a shaft 51, a rotor core 52, rotor end plates 53, and a steel sleeve 54. The rotor core 52 is located between the shaft 51 and the stator core 31. The rotor end plates 53 are located at both ends of the rotor core 52 and fitted onto the shaft 51. The steel sleeve 54 is located at both ends of the rotor end plates 53 and fitted onto the shaft 51. In addition, the rotor 5 is equipped with an internal circulation oil passage 55, which passes through the rotating shaft 51, rotor end plate 53, rotor core 52 and steel sleeve 54 in sequence, effectively reducing the temperature of the rotor 5.
[0035] like Figure 1 , Figure 3 and Figure 4 As shown, the oil baffle ring 4 includes a baffle 41 and a ring body 42. Limiting steps 13 are provided at both ends of the inner cavity of the base 1, and the baffle 41 is interference-fitted into the inner cavity of the base 1 and axially positioned by the limiting steps 13. Additionally, a groove 421 is provided on one side of the ring body 42, and a circular boss 531 is provided on one side of the rotor end plate 53. After assembly, the circular boss 531, the ring body 42, and the groove 421 combine to form a non-contact labyrinth seal groove, which acts as an oil seal when the rotor 5 rotates, preventing oil leakage.
[0036] like Figure 1 , Figure 2 and Figure 4 As shown, the base 1 is provided with an oil inlet 11 and a base oil hole 12. A partial oil cavity is formed between the base 1 and the oil baffle ring 4, and the partial oil cavity is interconnected with the oil inlet 11 and the base oil hole 12. Furthermore, the outer surface of the stator core 31 is provided with circumferentially distributed through oil grooves 311 along the axial direction, which connect the two partial oil cavities.
[0037] like Figure 1-2 As shown, the rear end cover 22 includes a rear end cover oil passage 221, a rear bearing chamber 222, a rear oil drain groove 223, and a rear end cover oil cavity 224. One end of the rear end cover oil passage 221 is aligned with and connected to the oil hole 12 of the machine base, and is sealed with a sealing ring; the other end is connected to the rear end cover oil cavity 224. Additionally, a plug and sealing ring are installed on the outer end of the rear end cover oil passage 221 to seal the oil inside the rear end cover 22. An oil inlet component 6 is bolted between the rear bearing chamber 222 and the rear end cover oil cavity 224. The oil inlet component 6 is connected to the rotating shaft 51 and has an axial oil hole. Inserting the axial oil hole into the internal circulation oil passage 55 on the rotating shaft 51 allows cooling oil to flow from the rear end cover oil cavity 224 into the internal circulation oil passage 55 inside the rotor 5. To reduce cooling oil leakage at the gap between the oil inlet component 6 and the rotating shaft 51, an oil seal 8 is installed between the oil inlet component 6 and the rotating shaft 51. The rear bearing chamber 222 is used to install the bearing 7. The bearing 7 is sleeved on the rotating shaft 51 and located on one side of the steel sleeve 54. The rear oil drain sump 223 is connected to the oil collection sump 15 through the oil drain port 14 on the machine base 1. The oil entering the rear end cover 22 can be discharged from the rear oil drain sump 223.
[0038] like Figure 1-2 As shown, the front cover 21 has a front bearing chamber 211 and a front oil drain groove 212. The front bearing chamber 211 is used to install the bearing 7, and the bearing 7 is sleeved on the other end of the rotating shaft 51 and located on one side of the steel sleeve 54. The front oil drain groove 212 is connected to the oil collection groove 15 through the oil drain port 14, and the oil entering the front cover 21 can be discharged from the front oil drain groove 212.
[0039] In addition, such as Figure 1-2 As shown, in order to cool the bearing 7, the internal circulation oil passage 55 is connected to the front bearing chamber 211 and the rear bearing chamber 222. When the rotor 5 rotates, the centrifugal pressure at both ends is equal. Since the cooling oil entering the internal circulation oil passage 55 has a certain flow rate and oil pressure, the cooling oil can be thrown out from the internal circulation oil passage 55 on the steel sleeve 54 while the rotor 5 is rotating, so as to lubricate and cool the bearing 7 in the front bearing chamber 211 and the rear bearing chamber 222.
[0040] like Figure 2 and4 As shown, the bottom of the base 1 is provided with an oil drain port 14 and an oil collection tank 15. The oil drain port 14 is located at both ends of the base 1 and connects to the oil collection tank 15. Oil discharged from the front drain tank 212 and the rear drain tank 223 flows through the oil drain port 14 on the base 1 into the oil collection tank 15. Additionally, a cover plate 16 is provided on the oil collection tank 15, which is fixedly connected to the oil collection tank 15 by bolts and sealed by a sealing ring. An oil outlet 161 is provided on the cover plate 16, which is used to connect an external oil pump and an oil cooler. The oil cooler cools the oil, while the oil pump re-introduces the cooled oil into the motor through the oil inlet 11, forming an oil circulation circuit and further improving the heat dissipation effect.
[0041] Working principle: During operation, cooling oil enters one side of the local oil chamber through the oil inlet 11 on the base 1, and then enters the other side of the local oil chamber along the through oil groove 311 on the outer surface of the stator core 31. The oil quickly fills both local oil chambers, ensuring full contact between the winding 32 and the stator core 31 and the cooling oil. This results in efficient and uniform heat dissipation of the winding 32, preventing significant local hot spots caused by the sprayed cooling oil not reaching the winding 32. The oil filling the local oil chambers enters the rear end cover oil passage 221 from the base oil hole 12 under a certain flow rate and pressure. It then enters the rear end cover oil chamber 224 along the rear end cover oil passage 221. From the rear end cover oil chamber 224, it enters the axial oil hole of the oil inlet component 6 and then only enters the internal circulation oil passage 55. After entering the internal circulation oil passage 55, the cooling oil cools the shaft 51, rotor end plate 53, rotor core 52, and steel sleeve 54. After being ejected from the internal circulation oil passage 55 of the rotor 5, the oil lubricates and cools the bearing 7. It then exits through the front drain oil groove 212 and the rear drain oil groove 223, and flows through the oil drain port 14 on the base 1 into the oil collection tank 15. Finally, the cooling oil exits through the oil outlet 161 on the cover plate 16 to the outside of the motor, where it is cooled by an oil cooler. The oil pump then pumps the cooled oil back into the motor through the oil inlet 11, forming a complete oil circulation circuit and improving the motor's heat dissipation efficiency.
[0042] Finally, it should be noted that the above description is only a preferred embodiment of this application and is not intended to limit this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.
Claims
1. An oil-cooled motor, characterized in that, include: A base (1) having an inner cavity; End cap (2), the end cap (2) includes a front end cap (21) and a rear end cap (22), the front end cap (21) and the rear end cap (22) are respectively connected to the two ends of the base (1); The stator (3) includes a stator core (31) sleeved in the inner cavity of the frame (1), and windings (32) are provided at both ends of the stator core (31). Oil baffle ring (4), the oil baffle ring is sleeved on both ends of the inner cavity of the machine base (1) and is axially limited by the machine base (1); The rotor (5) includes a rotating shaft (51), a rotor core (52), a rotor end plate (53), and a steel sleeve (54). The rotor core (52) is sleeved on the rotating shaft (51). The rotor end plate (53) is located at both ends of the rotor core (52) and sleeved on the rotating shaft (51). The steel sleeve (54) is located at both ends of the rotor end plate (53) and sleeved on the rotating shaft (51). The base (1) is provided with an oil inlet (11) and a base oil hole (12). A local oil cavity is formed between the base (1) and the oil baffle ring (4). The oil inlet (11) is connected to the local oil cavity, and the local oil cavity is connected to the base oil hole (12). A through oil groove (311) is axially distributed on the outer surface of the stator core (31). The through oil groove (311) is connected to the local oil cavity. A rear end cover oil passage (221) is provided inside the rear end cover (22). The rear end cover oil passage (221) is aligned with the base oil hole (12). An internal circulation oil passage (55) is provided inside the rotor (5). The internal circulation oil passage (55) passes through the rotating shaft (51), the rotor end plate (53), the rotor core (52), and the steel sleeve (54) in sequence.
2. The oil-cooled motor according to claim 1, characterized in that, The oil baffle ring (4) includes a baffle (41) and a ring body (42). The base (1) is also provided with limiting steps (13) at both ends. The baffle (41) is positioned by the limiting steps (13). A groove (421) is provided on one side of the ring body (42). A circular boss (531) is provided on one side of the rotor end plate (53). The circular boss (531) is combined with the ring body (42) and the groove (421) to form a non-contact labyrinth sealing groove.
3. The oil-cooled motor according to claim 1, characterized in that, The bottom of the base (1) is provided with an oil drain port (14) and an oil collection tank (15). The oil drain port (14) is located at both ends of the base (1) and is connected to the oil collection tank (15).
4. An oil-cooled motor according to claim 3, characterized in that, The rear end cover (22) is also provided with a rear bearing chamber (222), a rear oil drain groove (223) and a rear end cover oil cavity (224). The rear end cover oil cavity (224) is connected to the rear end cover oil passage (221). An oil inlet component (6) is provided between the rear bearing chamber (222) and the rear end cover oil cavity (224). The oil inlet component (6) is connected to the rotating shaft (51). A bearing (7) is installed in the rear bearing chamber (222). The rear oil drain groove (223) is connected to the oil collection groove (15) through the oil drain port (14).
5. An oil-cooled motor according to claim 4, characterized in that, The front end cover (21) is provided with a front bearing chamber (211) and a front oil drain groove (212). A bearing (7) is installed in the front bearing chamber (211), and the front oil drain groove (212) is connected to the oil collection groove (15) through the oil drain port (14).
6. An oil-cooled motor according to claim 5, characterized in that, The internal circulation oil passage (55) is connected to the front bearing chamber (211) and the rear bearing chamber (222).
7. An oil-cooled motor according to claim 3, characterized in that, The oil collection tank (15) is provided with a cover plate (16), and the cover plate (16) is provided with an oil outlet (161). The oil outlet (161) is used to connect an external oil pump and an oil cooler and then connect to the oil inlet (11) to form an oil circulation circuit.
8. An oil-cooled motor according to claim 4, characterized in that, An oil seal (8) is provided between the oil inlet component (6) and the rotating shaft (51).