Cooling structure for permanent magnet synchronous motor

Abstract

Cooling structure of permanent magnet synchronous motor, including casing, stator core, rotor assembly, the stator core includes middle iron core section, left and right iron core sections, left and right end face iron core sections, the inner circumference of each iron core section is provided with winding teeth, and the winding teeth positions correspond, the tooth part of end face iron core section is provided with oil injection hole at intervals, the yoke part is provided with oil inlet hole at intervals, the oil injection hole and the oil inlet hole are staggered, the tooth part of left and right iron core sections is provided with upstream large hole and downstream small hole at intervals, the upstream large hole extends from the tooth part to the yoke part and communicates with the oil inlet hole, the downstream small hole communicates with the oil injection hole, the tooth part of middle iron core section is provided with multiple trapezoidal oil through holes, the upstream large hole of left iron core section communicates with the downstream small hole of right iron core section through the trapezoidal oil through hole, the upstream large hole of right iron core section communicates with the downstream small hole of left iron core section through the trapezoidal oil through hole, the casing is provided with oil inlet port, which communicates with the oil storage sealed cavities on both sides, and then communicates with the oil inlet hole, the rotor assembly includes rotor core and rotor shaft, the rotor core is provided with oil through hole, the rotor shaft is hollow structure, and the circumference is provided with multiple oil holes.

Description

Technical Field

[0001] This invention relates to the field of drive motor technology for new energy pure electric vehicles, and in particular to a cooling structure for a permanent magnet synchronous motor. Background Technology

[0002] As the core component of new energy vehicles, the drive motor's performance largely determines the vehicle's overall performance. Currently, the drive motors in new energy vehicles primarily utilize oil-cooled permanent magnet synchronous motors, which offer high power and torque, high power density, and small size, satisfying the demands for higher acceleration performance and more spacious interiors. However, excessively high power density and a small size can lead to high heat generation per unit volume, posing a risk of overheating and potentially burning out the motor, thus compromising the safety of the new energy vehicle.

[0003] To address these issues, existing technologies primarily involve slotting the outer circumference of the stator and designing sealing oil reservoir rings at both ends of the housing. Oil injection holes are located on these oil reservoir rings. Cooling oil flows from the housing to the slots on the outer circumference of the stator, cooling the stator core, and then flows to the sealing oil reservoir rings at both ends, cooling the windings through the oil injection holes. The temperature of each stator component is reduced through convective heat transfer between the cooling oil and the stator components.

[0004] However, existing technologies have limited cooling effects on areas of severe heat generation in the stator teeth. Increasing the size of the outer groove reduces the motor's output torque, affecting motor performance. Furthermore, the complex structure of the end-sealing oil reservoir ring increases the cost of the cooling structure for the permanent magnet synchronous motor. In this invention, the cooling oil flows directly to the oil reservoir sealing cavities at both ends after entering the motor. Two oil paths are formed through the oil inlet holes on the left and right end core sections that connect to the oil reservoir sealing cavities, allowing the oil to enter the stator interior and cool the areas of severe heat generation in the stator teeth. Simultaneously, the oil is sprayed directly onto the stator windings through the oil spray oblique holes on the oil reservoir sealing cavities, further cooling the stator windings. This results in a better cooling effect and replaces the complex sealing oil reservoir ring in the existing technology with a simpler oil reservoir sealing cavity, reducing manufacturing costs. Summary of the Invention

[0005] In view of the problems existing in the prior art, the present invention provides a cooling structure for a permanent magnet synchronous motor, which has a simple structure, good cooling effect, simple manufacturing process, and low manufacturing cost.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: a cooling structure for a permanent magnet synchronous motor, comprising a motor housing, a stator core, and a rotor assembly. The stator core includes a central core segment located in the middle of the core, left and right core segments located on either side of the central core segment, and end-face core segments located on the left and right end faces of the core. Each core segment has a plurality of winding teeth evenly distributed on its inner circumference, and the winding teeth of each core segment are positioned correspondingly. The teeth of the end-face core segments are provided with oil spray holes spaced apart, and the yoke is provided with oil inlet holes spaced apart. The oil spray holes and oil inlet holes are arranged alternately. The teeth of the left and right core segments are provided with alternating upstream large holes and downstream small holes. The upstream large holes extend from the teeth to the yoke and the yoke of the end-face core segments. The oil inlet holes are interconnected, and the downstream small hole is connected to the oil spray hole of the toothed part of the end face iron core section. The toothed part of the middle iron core section is provided with multiple trapezoidal oil passage holes. The upstream large hole of the left iron core section is connected to the downstream small hole of the right iron core section through the trapezoidal oil passage hole. The upstream large hole of the right iron core section is connected to the downstream small hole of the left iron core section through the trapezoidal oil passage hole. The motor housing is provided with an oil inlet port. The oil inlet port is connected to the oil storage sealing cavity on both sides of the motor through an oil passage. The oil storage sealing cavity is connected to the oil inlet hole of the end face iron core section. The rotor assembly includes a rotor iron core and a rotor shaft. The rotor iron core is provided with an oil passage hole. The rotor shaft is a hollow structure and has multiple oil holes in the circumferential direction of the rotor shaft.

[0007] Preferably, the diameter of the oil inlet hole on the end face iron core section is larger than the diameter of the oil injection hole.

[0008] Preferably, the intermediate core section teeth have three trapezoidal oil passages arranged in a triangular pattern, and the sum of the distances from the two inclined sides of the trapezoidal oil passages to the edge of the teeth is greater than or equal to the minimum width of the teeth.

[0009] Preferably, the oil storage sealing cavity is provided with an angled oil injection hole.

[0010] Preferably, the stator cooling oil circuit is as follows: cooling oil enters the motor from the oil inlet port on the housing and then splits into left and right streams. One stream flows to the left oil storage and sealing cavity, through the oil inlet on the left end face iron core section, through the upstream large hole of the left iron core section, the trapezoidal oil passage of the middle iron core section, and the downstream small hole of the right iron core section, and finally sprays out from the oil spray hole on the right end face iron core section; the other stream flows to the right oil storage and sealing cavity, through the oil inlet on the right end face iron core section, through the upstream large hole of the right iron core section, the trapezoidal oil passage of the middle iron core section, and the downstream small hole of the left iron core section, and finally sprays out from the oil spray hole on the left end face iron core section.

[0011] Preferably, the oil passage is located on the rotor core near the permanent magnet.

[0012] Furthermore, a drive motor employs the cooling structure of the permanent magnet synchronous motor described in claim 1.

[0013] Furthermore, an automobile whose drive motor employs a permanent magnet synchronous motor with a cooling structure as described in claim 1.

[0014] The beneficial effects of this invention are: The cooling structure of the permanent magnet synchronous motor of this invention features a cooling oil passage for the stator assembly located at the teeth of the stator core. Cooling oil flows through this passage, effectively dissipating heat from areas of high heat concentration within the stator assembly. This cooling effect is significantly more pronounced compared to existing drive motor solutions that only cool the outer periphery of the stator core. Furthermore, three trapezoidal oil passages are provided in the teeth of the middle core section, increasing the contact area between the cooling oil and the core, further enhancing the cooling effect. Additionally, the sum of the distances from the two inclined sides of each trapezoidal oil passage to the edge of the teeth is greater than or equal to the minimum width of the teeth, minimizing the impact on the motor's electromagnetic performance. In the rotor assembly cooling circuit, oil passages are provided on the rotor core near the permanent magnet, enabling heat dissipation from areas of high heat concentration in the rotor assembly and reducing rotor temperature. See also... Figure 10 Under typical harsh operating conditions of a certain vehicle model, the highest temperature simulated by this invention is 18% lower than that of the prior art. Compared with the existing technical solutions, the motor system has a better cooling effect and a lower temperature, which greatly increases the reliability of the motor under severe heat conditions. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the motor structure of the present invention; Figure 2 This is a schematic diagram of the stator core explosion of the present invention; Figure 3 This is a schematic diagram of the end face iron core section structure of the present invention; Figure 4 yes Figure 3 Enlarged view of point A; Figure 5 This is a schematic diagram of the core section structure of the present invention; Figure 6 yes Figure 5 Enlarged view of point B; Figure 7 This is a schematic diagram of the intermediate iron core section structure of the present invention; Figure 8 yes Figure 7 Enlarged view of point C; Figure 9 This is a schematic diagram of the rotor core of the present invention.

[0016] Figure 10 This is a schematic diagram comparing the simulated temperature of the motor of this invention with that of existing motors. Detailed Implementation

[0017] See Figures 1 to 9A cooling structure for a permanent magnet synchronous motor includes a motor housing, a stator core, and a rotor assembly. The stator core includes a central core section 3 located in the middle of the core, left and right core sections 2 located on both sides of the central core section 3, and end face core sections 1 located on the left and right end faces of the core. Each core section has a plurality of winding teeth evenly arranged on its inner circumference, and the winding teeth of each core section are positioned correspondingly. The end face core sections 1 have oil spray holes 12 spaced apart on their teeth and oil inlet holes 11 spaced apart on their yokes. The oil spray holes 12 and oil inlet holes 11 are arranged alternately. The diameter of the oil inlet holes 11 on the end face core sections 1 is larger than the diameter of the oil spray holes 12. This arrangement ensures that there is sufficient distance between the oil inlet holes and the oil spray holes to accommodate a sealing structure. Moreover, the oil spray holes are located on the teeth of the stator core, which can cool the inner side of the stator winding ends, ensuring more uniform cooling of the stator windings. The left and right core segments 2 have staggered upstream large holes 21 and downstream small holes 22. The upstream large holes 21 extend from the teeth to the yoke and communicate with the oil inlet 11 of the yoke of the end core segment 1. The downstream small holes 22 communicate with the oil spray holes 12 of the teeth of the end core segment 1. The middle core segment 3 has multiple trapezoidal oil passages 31 on each tooth. There are three trapezoidal oil passages 31 on each tooth of the middle core segment 3, arranged in a triangle to increase the contact area between the cooling oil and the stator core, thus improving the cooling effect on the stator core. The sum of the distances from the two inclined sides of the trapezoidal oil passage 31 to the edge of the tooth is greater than or equal to the minimum width of the tooth, which minimizes the impact on the magnetic flux path of the motor and reduces the impact on electromagnetic performance. The large upstream hole 21 of the left iron core segment is connected to the small downstream hole 22 of the right iron core segment through the trapezoidal oil passage 31, and the large upstream hole 21 of the right iron core segment is connected to the small downstream hole 22 of the left iron core segment through the trapezoidal oil passage 31, so that the oil circuit in the stator iron core is divided into two paths, which dissipates heat from the toothed yoke part of the motor stator that is seriously heated, and cools the inner side of the stator winding end. Compared with the existing drive motor scheme that dissipates heat from the outer periphery of the stator iron core, the cooling effect is more obvious. The motor housing is provided with an oil inlet port 7, which is connected to the oil storage sealing cavities 5 on both sides of the motor through an oil passage. The oil storage sealing cavities 5 are connected to the oil inlet holes 11 on the end face iron core section, forming a stator cooling oil passage. The stator cooling oil passage is as follows: after the cooling oil enters the motor from the oil inlet port 7 on the motor housing, it splits into left and right streams. One stream flows to the left oil storage sealing cavity 5, through the oil inlet hole 11 on the left end face iron core section, through the upstream large hole 21 of the left iron core section, the trapezoidal oil passage hole 31 of the middle iron core section 3, and the downstream small hole 22 of the right iron core section, and finally sprays out from the oil spray hole 12 on the right end face iron core section. The other stream flows to the right oil storage sealing cavity 5, through the oil inlet hole 11 on the right end face iron core section, through the upstream large hole 21 of the right iron core section, the trapezoidal oil passage hole 31 of the middle iron core section 3, and the downstream small hole (22) of the left iron core section, and finally sprays out from the oil spray hole 12 on the left end face iron core section. The oil storage sealing cavity 5 is provided with an oil spray oblique hole, which can make the motor end winding cooler more fully and evenly.The rotor assembly includes a rotor core and a rotor shaft 4. The rotor core has oil passages 6 located near the permanent magnet, which dissipate heat from the hottest parts of the rotor assembly, reducing the rotor temperature. The rotor shaft 4 is hollow and has multiple oil holes 41 along its circumference, forming a rotor cooling oil path. Part of the cooling oil flows through the oil holes 41 to cool the stator windings, while another part flows through the oil holes 41, across the rotor end plates, and into the rotor interior to cool it.

[0018] The cooling oil circuit of the permanent magnet synchronous motor cooling structure in this embodiment of the invention is as follows: On one hand, cooling oil enters the motor from the oil inlet port 7 on the motor housing. After entering the motor, the cooling oil is split at both ends of the motor and then enters the oil storage sealing chambers 5 at both ends of the motor. At this time, a portion of the cooling oil in the oil storage sealing chamber 5 at the left end sprays the motor winding end through the oil spray oblique hole on the oil storage sealing chamber 5 to cool the winding end. The other portion of the cooling oil flows into the stator core through the oil inlet hole 11 on the left end face core section, and then flows through the upstream large hole 21 of the left core section, the trapezoidal oil passage hole 31 of the middle core section 3, and the downstream small hole 22 of the right core section to cool the teeth of the stator core that are severely overheated. Finally, the oil is sprayed out from the oil spray hole 12 on the right end of the iron core section to cool the stator winding. Moreover, since the oil flows in from the large hole and out from the small hole, the residence time of the cooling oil is increased, resulting in a better cooling effect. Similarly, part of the cooling oil in the oil storage sealing cavity 5 on the right end sprays the end of the motor winding through the oil spray oblique hole on the oil storage sealing cavity 5 to cool the end of the winding. Another part of the cooling oil flows into the stator iron core through the oil inlet hole 11 on the right end of the iron core section, and then flows through the upstream large hole 21 of the right iron core section, the trapezoidal oil passage hole 31 of the middle iron core section 3, and the downstream small hole 22 of the left iron core section to cool the teeth of the stator iron core that are severely heated. Finally, the oil is sprayed out from the oil spray hole 12 on the left end of the iron core section to cool the stator winding. On the other hand, since the rotor shaft 4 is a hollow structure, the cooling oil directly enters the interior of the rotor shaft 4. Then, the cooling oil flows into the stator winding and the rotor end plate through the oil hole 41 in the circumferential direction inside the rotor shaft, and cools the stator winding and the rotor end plate. At the same time, the cooling oil flowing into the rotor end plate will continue to flow into the rotor core and cool the rotor through the oil passage 6 on the rotor core.

[0019] Furthermore, a drive motor employs the cooling structure of the permanent magnet synchronous motor.

[0020] Furthermore, there is a type of automobile whose drive motor is a permanent magnet synchronous motor with a cooling structure of the aforementioned permanent magnet synchronous motor.

[0021] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications made to the present invention by those skilled in the art without departing from the spirit of the present invention shall fall within the protection scope of the present invention.

Claims

1. A cooling structure for a permanent magnet synchronous motor, comprising a motor housing, a stator core, and a rotor assembly, characterized in that: The stator core includes a middle core section (3) located in the middle of the stator core, left and right core sections (2) located on both sides of the middle core section (3), and end face core sections (1) located on the left and right end faces of the stator core. Each core section has a number of winding teeth evenly arranged on its inner circumference, and the winding teeth of each core section are in corresponding positions. The teeth of the end face core section (1) are provided with oil injection holes (12) at intervals, and the yoke is provided with oil inlet holes (11) at intervals. The oil injection holes (12) and oil inlet holes (11) are arranged alternately. The teeth of the left and right core sections (2) are provided with upstream large holes (21) and downstream small holes (22) alternately. The upstream large hole (21) extends from the tooth to the yoke and communicates with the oil inlet hole (11) of the yoke of the end face iron core section (1). The downstream small hole (22) communicates with the oil spray hole (12) of the tooth of the end face iron core section (1). The teeth of the middle iron core section (3) are provided with multiple trapezoidal oil passage holes (31). The upstream large hole (21) of the left iron core section communicates with the downstream small hole (22) of the right iron core section through the trapezoidal oil passage hole (31). The upstream large hole (21) of the right iron core section communicates with the downstream small hole (22) of the left iron core section through the trapezoidal oil passage hole (31). The motor housing is provided with an oil inlet port (7). The oil inlet port (7) is connected to the oil storage sealing cavities (5) on both sides of the motor through the oil passage. The oil storage sealing cavity (5) is connected to the oil inlet hole (11) of the end face iron core section, forming a stator cooling oil passage. The stator cooling oil passage is as follows: the cooling oil enters the motor from the oil inlet port (7) on the motor housing and then splits into left and right streams. One stream flows to the left oil storage sealing cavity (5), through the oil inlet hole (11) on the left end face iron core section, through the upstream large hole (21) of the left iron core section, the trapezoidal oil passage hole (31) of the middle iron core section (3), and the downstream small hole (22) of the right iron core section, and finally flows out from the right end face iron core. The oil sprays out through the spray hole (12) on the section; another path flows to the right oil storage sealing cavity (5), through the oil inlet hole (11) on the right end face iron core section, through the upstream large hole (21) of the right iron core section, the trapezoidal oil passage hole (31) of the middle iron core section (3), and the downstream small hole (22) of the left iron core section, and finally sprays out from the spray hole (12) on the left end face iron core section; the rotor assembly includes a rotor iron core and a rotor shaft (4), the rotor iron core is provided with an oil passage hole (6), the rotor shaft (4) is a hollow structure, and the rotor shaft (4) is provided with multiple oil holes (41) in the circumferential direction, forming a rotor cooling oil circuit.

2. The cooling structure of the permanent magnet synchronous motor according to claim 1, characterized in that: The diameter of the oil inlet hole (11) on the end face iron core section (1) is larger than the diameter of the oil spray hole (12).

3. The cooling structure of the permanent magnet synchronous motor according to claim 1, characterized in that: The intermediate iron core section (3) has three trapezoidal oil passage holes (31) in the tooth section. The three trapezoidal oil passage holes (31) are arranged in a triangle. The sum of the distances from the two inclined sides of the trapezoidal oil passage holes (31) to the edge of the tooth section is greater than or equal to the minimum width of the tooth section.

4. The cooling structure of the permanent magnet synchronous motor according to claim 1, characterized in that: An oil spraying oblique hole is provided on the oil storage sealing cavity (5).

5. The cooling structure of the permanent magnet synchronous motor according to claim 1, characterized in that: The oil passage (6) is located on the rotor core near the permanent magnet.

6. A drive motor, characterized in that: The drive motor adopts the cooling structure of the permanent magnet synchronous motor as described in claim 1.

7. A car, characterized in that: The vehicle's drive motor is a permanent magnet synchronous motor with the cooling structure of the permanent magnet synchronous motor described in claim 1.

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