Motor cooling structure

Abstract

Motor cooling structure, including motor shell, 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 outer circumference of each iron core section is equipped with a plurality of winding teeth, the position of winding teeth corresponds, the outer circle radius of left and right iron core sections, left and right end face iron core sections is same, the outer circle radius of middle iron core section is less than the radius of end face iron core section, a plurality of rectangular oil inlet grooves are arranged on the outer circumference of middle iron core section, and the position corresponds with tooth part, a plurality of first rectangular oil storage grooves are arranged on left and right iron core sections from yoke part to tooth part, and the groove part located in yoke part is communicated with rectangular oil inlet groove, a plurality of second rectangular oil storage grooves are arranged on end face iron core section from yoke part to tooth part and communicated with first rectangular oil storage groove, the rotor assembly includes rotor core and rotor shaft, a plurality of oil through holes are arranged on rotor core, the rotor shaft is hollow structure, and a plurality of oil holes are arranged on the circumference, each stator core section is overlapped and installed into the shell, and annular oil storage groove is formed between middle iron core section and shell.

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 motor cooling structure. Background Technology

[0002] Oil-cooled permanent magnet synchronous motors are often used as drive motors for new energy vehicles because of their high power and torque, high power density, and small size. However, due to their high power density and small size, the motor generates a lot of heat per unit volume, which poses a risk of overheating. In severe cases, the motor may even burn out, causing safety hazards.

[0003] To address these issues, existing technologies primarily employ slotting on the outer circumference of the stator and designing sealing oil reservoirs at both ends of the motor housing, with oil spray holes on these rings. Cooling oil flows from the housing to the slotted outer circumference of the stator, cooling the stator core, then flows to the oil reservoirs at both ends, and cools the windings through the oil spray holes. The temperature of each stator component is reduced through convective heat transfer between the cooling oil and the stator components. However, this technology has limited cooling effectiveness in areas of severe heat generation, such as the stator teeth. Increasing the size of the slots on the outer circumference to enhance cooling capacity would significantly reduce the motor's output torque, affecting motor performance. Furthermore, the complex structure of the oil reservoirs and spray rings at the ends increases motor cost. Additionally, the poor surface flatness of the stator core makes sealing difficult, leading to oil leakage and reduced cooling efficiency. Summary of the Invention

[0004] To address the problems existing in the prior art, the present invention provides a motor cooling structure that is simple in structure, requires no oil injection ring, and has a good cooling effect on areas of severe heat generation in the stator teeth. The motor manufacturing process is also simple.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows: a motor cooling structure, comprising a motor housing, a stator core, and a rotor assembly. The stator core includes a central core section located in the middle of the core, left and right core sections located on either side of the central core section, and end-face core sections located on the left and right end faces of the core. Each core section has a plurality of winding teeth on its inner circumference, and the winding teeth of each core section are positioned correspondingly. The outer radii of the left and right core sections and the end-face core sections on the left and right end faces are the same. The outer radius of the central core section is smaller than the radii of the left and right core sections. The outer circumference of the yoke portion of the central core section is provided with a plurality of rectangular oil inlet grooves, the positions of which are aligned with the teeth. The left and right iron core sections are provided with a plurality of first rectangular oil storage grooves, which extend from the yoke to the tooth section, and the groove of the first rectangular oil storage groove located at the yoke position communicates with the rectangular oil inlet groove. The end face iron core section is provided with a plurality of second rectangular oil storage grooves, which extend from the yoke to the tooth section, and the second rectangular oil storage grooves communicate with the first rectangular oil storage grooves. The rotor assembly includes a rotor iron core and a rotor shaft. The rotor iron core is provided with a plurality of oil passage holes. The rotor shaft is a hollow structure and is provided with a plurality of oil holes in the circumferential direction. The stator iron core sections are stacked and installed into the motor housing, and an annular oil storage groove is formed between the middle iron core section and the motor housing.

[0006] Preferably, the first rectangular oil reservoir has a plurality of first semi-circular oil injection holes on the other side of the groove edge along the tooth center line connected to the first rectangular oil reservoir, and the second rectangular oil reservoir has a plurality of second semi-circular oil injection holes on the other side of the groove edge along the tooth center line connected to the second rectangular oil reservoir, and the first semi-circular oil injection holes of the first rectangular oil reservoir and the second semi-circular oil injection holes of the second rectangular oil reservoir form a circular oil injection hole.

[0007] Preferably, the minimum distance between the long side of the first rectangular oil reservoir and the two sides of the tooth is greater than or equal to twice the minimum width of the tooth.

[0008] Preferably, twice the minimum distance between the long side of the second rectangular oil reservoir and the two sides of the tooth is greater than or equal to the minimum width of the tooth.

[0009] Preferably, the motor housing is provided with an oil inlet and oil storage chambers at both ends. The oil inlet is connected to the central annular oil groove and the oil storage chambers at both ends, and the oil storage chambers are provided with multiple oil injection holes.

[0010] Preferably, the oil passage is located on the rotor core near the permanent magnet.

[0011] Preferably, the stator cooling oil circuit is as follows: cooling oil flows from the oil inlet on the motor housing to the annular oil reservoir in the middle. The cooling oil in the annular oil reservoir flows into the rectangular oil inlet of the middle iron core section and then splits into left and right streams. One stream flows to the first rectangular oil reservoir on the left iron core section, then to the second rectangular oil reservoir on the left end face iron core section and is sprayed out; the other stream flows to the first rectangular oil reservoir on the right iron core section, then to the second rectangular oil reservoir on the right end face iron core section and is sprayed out.

[0012] Furthermore, a drive motor employs the aforementioned motor cooling structure.

[0013] Furthermore, there is a type of automobile whose drive motor is a permanent magnet synchronous motor employing the aforementioned motor cooling structure.

[0014] Benefits of the present invention:

[0015] The motor cooling structure of this invention features a cooling oil passage for the stator assembly located at the stator core teeth. Cooling oil flows through this passage to dissipate heat from the most heat-generating parts of the stator assembly. This cooling effect is significantly more pronounced compared to existing drive motor solutions that only dissipate heat from the outer periphery of the stator core. Furthermore, the motor uses only two types of stator laminations, simplifying the manufacturing process and reducing production costs. Simultaneously, the motor eliminates the need for complex sealing structures, simplifying manufacturing and reducing the number and cost of components. In the rotor assembly cooling circuit, oil passages are provided on the rotor core near the permanent magnets to dissipate heat from the most heat-generating parts of the rotor assembly, thus lowering the rotor temperature. See also... Figure 10 Under typical harsh operating conditions for a certain vehicle model, the highest temperature simulated by this invention is 20% lower than that of existing technologies. Compared with existing solutions, the motor structure exhibits better cooling and lower temperatures, significantly increasing the reliability of the motor under high-heat conditions. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the motor structure of the present invention;

[0017] Figure 2 This is an exploded view of the stator core of the present invention;

[0018] Figure 3 This is a schematic diagram of the structure of the intermediate iron core section of the present invention;

[0019] Figure 4 This is a schematic diagram of the core section of the present invention;

[0020] Figure 5 yes Figure 4 Enlarged view of point A;

[0021] Figure 6This is a schematic diagram of the end face core section of the present invention;

[0022] Figure 7 yes Figure 6 Enlarged view of point B;

[0023] Figure 8 This is a schematic diagram of the motor end cover of the present invention;

[0024] Figure 9 This is a schematic diagram of the rotor core of the present invention;

[0025] Figure 10 This is a schematic diagram comparing the simulated temperature of the motor of this invention with that of existing motors. Detailed Implementation

[0026] See Figures 1 to 9A motor cooling structure includes a motor housing, a stator core, and a rotor assembly. The stator core includes a central core segment 1 located in the middle of the core, left and right core segments 2 located on either side of the central core segment 1, and end face core segments 3 located on the left and right end faces of the core. Each core segment has a plurality of winding teeth on its inner circumference, and the winding teeth of each core segment are positioned correspondingly. The outer radii of the left and right core segments 2 and the end face core segments 3 on the left and right end faces are the same, and the outer radius of the central core segment 1 is smaller than the radii of the left and right core segments 2. The outer circumference of the yoke of the central core segment 1 has a plurality of rectangular oil inlet grooves 11, the positions of which correspond to the teeth. The left and right core segments 2 have a plurality of first rectangular oil storage grooves 21, the length of which is twice the minimum distance from the edges of the teeth to be greater than or equal to the minimum width of the teeth. This minimizes the impact on the magnetic flux path of the motor, thereby reducing the impact on electromagnetic performance. The first rectangular oil reservoir 21 extends from the yoke to the tooth, and the groove of the first rectangular oil reservoir 21 located at the yoke is connected to the rectangular oil inlet groove 11. The end face iron core section 3 is provided with a plurality of second rectangular oil reservoirs 31. The minimum distance between the long side of the second rectangular oil reservoir 31 and the two sides of the tooth edge is greater than or equal to twice the minimum width of the tooth. This minimizes the impact on the magnetic flux path of the motor, thereby reducing the impact on electromagnetic performance. The second rectangular oil reservoir 31 extends from the yoke to the tooth section, and the second rectangular oil reservoir 31 communicates with the first rectangular oil reservoir 21 to form a stator cooling oil circuit. The stator cooling oil circuit is such that the cooling oil flows from the oil inlet 7 on the motor housing to the annular oil reservoir in the middle. The cooling oil in the annular oil reservoir flows into the rectangular oil inlet 11 of the middle iron core section 1 and then splits into left and right streams. One stream flows to the first rectangular oil reservoir 21 on the left iron core section, and then flows to the second rectangular oil reservoir 31 on the left end iron core section and sprays out. The other stream flows to the first rectangular oil reservoir 21 on the right iron core section, and then flows to the second rectangular oil reservoir 31 on the right end iron core section and sprays out. The first rectangular oil reservoir 21 has multiple first semi-circular oil spray holes 22 connected to it on the other side of the groove edge along the tooth center line. The second rectangular oil reservoir 31 has multiple second semi-circular oil spray holes 32 connected to it on the other side of the groove edge along the tooth center line. The first semi-circular oil spray holes 22 of the first rectangular oil reservoir 21 and the second semi-circular oil spray holes 32 of the second rectangular oil reservoir 31 form a circular oil spray hole. The number and position of the circular oil spray holes can be adjusted according to the motor's heat generation, thereby regulating the flow rate of the cooling oil and improving the motor's cooling effect. The rotor assembly includes a rotor core and a rotor shaft 5. The rotor core has multiple oil passage holes 6, which are located near the permanent magnet on the rotor core. These oil passage holes can dissipate heat from the parts of the motor rotor assembly that generate significant heat, thus reducing the rotor temperature. The rotor shaft 5 has a hollow structure, and multiple oil holes 51 are provided on its circumference, forming a rotor cooling oil path.The stator core segments are stacked and installed into the motor housing, forming an annular oil reservoir between the middle core segment 1 and the motor housing. The motor housing has an oil inlet 7 and oil storage chambers 4 at both ends. The oil inlet 7 communicates with the central annular oil reservoir and the oil storage chambers 4 at both ends, respectively. Each oil storage chamber 4 has multiple oil spray holes 41. This design allows for sufficient cooling of areas where the motor windings and stator cores experience severe heat generation, significantly reducing the motor temperature. Furthermore, the end caps can be rigidly sealed directly, eliminating the need for plastic sealing rings, simplifying manufacturing and reducing the number of components and cost of the motor structure.

[0027] The cooling oil circuit of the motor cooling structure in this embodiment of the invention is as follows: On one hand, the cooling oil flows through the oil inlet 7 on the motor housing to the annular oil storage tank in the middle and the oil storage chambers 4 at both ends. The cooling oil in the oil storage chambers 4 at both ends sprays the stator winding directly to cool it down through the oil spray hole 41. The cooling oil in the annular oil storage tank flows into the rectangular oil inlet 11 of the middle iron core section 1. Then, the cooling oil in the rectangular oil inlet 11 flows into the first rectangular oil storage tank 21 on the left and right sides of the iron core section 2. Then, it flows through the first rectangular oil storage tank 21 and the first semi-circular oil spray hole 22 connected to the first rectangular oil storage tank 21 to the second rectangular oil storage tank 31 and the second semi-circular oil spray hole 32 connected to the second rectangular oil storage tank 31, cooling the teeth and yoke of the stator iron core that are severely heated. Moreover, since the cooling oil can only be sprayed out from the circular oil spray hole, the cooling oil will stay in the first rectangular oil storage tank 21 for a longer time, making the cooling effect better. Finally, the oil is sprayed out through a circular spray hole formed by the first semicircular oil spray hole 22 and the second semicircular oil spray hole 32 to cool the inner side of the stator winding end. The cooling effect is more obvious compared to the existing drive motor solution that dissipates heat from the outer periphery of the stator core. 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 hole 6 on the rotor core.

[0028] Furthermore, a drive motor employs the aforementioned motor cooling structure.

[0029] Furthermore, there is a type of automobile whose drive motor is a permanent magnet synchronous motor employing the aforementioned motor cooling structure.

[0030] 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 motor cooling structure, comprising a motor housing, a stator core, and a rotor assembly, characterized in that: The stator core includes a central core section (1) located in the middle of the core, left and right core sections (2) located on both sides of the central core section (1), and end face core sections (3) located on the left and right end faces of the core. Each core section has several winding teeth on its inner circumference, and the winding teeth of each core section are in corresponding positions. The outer radii of the left and right core sections (2) and the end face core sections (3) on the left and right end faces are the same. The outer radius of the central core section (1) is smaller than the radius of the left and right core sections (2). The outer circumference of the yoke section (1) is provided with several rectangular oil inlet grooves (11), the position of which corresponds to the tooth section. The left and right iron core sections (2) are provided with several first rectangular oil storage grooves (21), which extend from the yoke section to the tooth section. The groove of the first rectangular oil storage groove (21) located at the yoke section is connected to the rectangular oil inlet groove (11). The end face iron core section (3) is provided with several second rectangular oil storage grooves (31). Extending from the yoke to the tooth, the second rectangular oil reservoir (31) communicates with the first rectangular oil reservoir (21), forming a stator cooling oil passage; the first rectangular oil reservoir (21) has multiple first semi-circular oil injection holes (22) connected to the first rectangular oil reservoir (21) on the other side of the groove edge on the tooth centerline, and the second rectangular oil reservoir (31) has multiple second semi-circular oil injection holes (32) connected to the second rectangular oil reservoir (31) on the other side of the groove edge on the tooth centerline, and the first rectangular oil reservoir (21) The first semicircular oil injection hole (22) of the first rectangular oil reservoir (31) and the second semicircular oil injection hole (32) of the second rectangular oil reservoir (31) form a circular oil injection hole. The rotor assembly includes a rotor core and a rotor shaft (5). The rotor core is provided with multiple oil passage holes (6). The rotor shaft (5) is a hollow structure, and the rotor shaft (5) is provided with multiple oil holes (51) in the circumferential direction to form a rotor cooling oil circuit. The stator core segments are stacked and installed into the motor housing. The intermediate core segment (1) and the motor housing form an annular oil reservoir.

2. The motor cooling structure according to claim 1, characterized in that: The minimum distance between the long side of the first rectangular oil reservoir (21) and the two sides of the tooth is greater than or equal to the minimum width of the tooth.

3. The motor cooling structure according to claim 1, characterized in that: The minimum distance between the long side of the second rectangular oil reservoir (31) and the two sides of the tooth is greater than or equal to the minimum width of the tooth.

4. The motor cooling structure according to claim 1, characterized in that: The motor housing is provided with an oil inlet (7) and oil storage chambers (4) at both ends. The oil inlet (7) is connected to the annular oil storage tank in the middle and the oil storage chambers (4) at both ends. The oil storage chambers (4) are provided with multiple oil injection holes (41).

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

6. The motor cooling structure according to claim 1, characterized in that: The stator cooling oil circuit is as follows: the cooling oil flows from the oil inlet (7) on the motor housing to the annular oil reservoir in the middle. The cooling oil in the annular oil reservoir flows into the rectangular oil inlet (11) of the middle iron core section (1) and then splits into left and right streams. One stream flows to the first rectangular oil reservoir (21) on the left iron core section, and then flows to the second rectangular oil reservoir (31) on the left end iron core section and sprays out. The other stream flows to the first rectangular oil reservoir (21) on the right iron core section, and then flows to the second rectangular oil reservoir (31) on the right end iron core section and sprays out.

7. A drive motor, characterized in that: The drive motor adopts the motor cooling structure described in claim 1.

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

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