Cooling structure for motor
By guiding the cooling oil within a specific range of the guide section in the circumferential direction of the stator core, the problem of insufficient cooling on the lower side of the coil end is solved, thus improving cost-effectiveness.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- TOYOTA JIDOSHA KK
- Filing Date
- 2025-07-25
- Publication Date
- 2026-07-31
AI Technical Summary
In existing motor cooling structures, the lower part of the coil end is difficult to fully contact the cooling oil, resulting in poor cooling effect and increased cost.
Guide sections are provided only at the bottom of the stator core within a 90-degree range on both sides to guide the cooling oil to the lower part of the coil end and to the upper part by gravity, thereby reducing the material used in the guide sections.
This achieves effective cooling of the underside of the coil end while reducing the cost of the cooling system.
Smart Images
Figure CN224582963U_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to a cooling structure for a motor. Background Technology
[0002] Conventionally, a cooling structure for a motor has been proposed, comprising: a stator having a stator core and stator coils; a housing for fixing the stator; and a pump for discharging cooling oil (see, for example, Patent Document 1). In this motor cooling structure, a cooling oil passage is provided in the housing to guide the cooling oil discharged from the pump. Furthermore, a coil end cover is provided to cover the portion of the stator coils that is axially offset from the stator core, i.e., the coil end. Moreover, a gap is formed between the coil end cover and the coil end, approximately the entire surface of the coil end cover opposite to the coil end, to guide the cooling oil from the cooling oil passage.
[0003] Patent Document 1: Japanese Patent Application Publication No. 2018-14857
[0004] In the aforementioned motor cooling structure, although the coil end cover covers approximately the entire surface opposite the coil end, even without the coil end cover in the upper circumferential portion of the coil end (e.g., within a 90-degree range from the uppermost point in the circumferential direction to both sides), cooling oil from the cooling oil passage can be applied to the coil end by gravity. Conversely, if the coil end cover itself is removed, it becomes difficult to ensure sufficient contact between the cooling oil from the cooling oil passage and the lower (vertically lower) portion of the coil end. Therefore, a cost reduction is sought while ensuring the application of cooling oil to the lower portion of the coil end. Utility Model Content
[0005] The main objective of the motor cooling structure disclosed herein is to reduce costs while ensuring the supply of cooling oil to the lower portion of the coil end.
[0006] The cooling structure of the motor disclosed herein employs the following mechanism to achieve the aforementioned main objectives.
[0007] This disclosure relates to a cooling structure for a motor having a stator comprising: an annular stator core; and a stator coil wound around the stator core and having coil ends protruding from both sides of the stator core in an axial direction. The main feature of the cooling structure is that it includes: a plurality of oil passages spaced apart in the circumferential direction of the stator core and respectively penetrating the stator core in the axial direction; and a guide portion disposed at one end of the stator core in the axial direction, which guides cooling oil flowing in a portion of the plurality of oil passages to the coil ends. The guide portion is configured to extend only a portion along the circumferential direction at least a portion of the portion extending 90 degrees to each side from the lowest point in the circumferential direction, beyond the outer periphery of the coil ends.
[0008] In the cooling structure of the motor of this invention, a guide portion is provided at one end of the stator core along the axial direction, guiding cooling oil flowing through a portion of multiple oil passages to the coil end. Furthermore, the guide portion is configured to extend circumferentially only in a range of 90 degrees to each side from the lowest point in the circumferential direction, closer to the outer periphery of the coil end. Thus, cooling oil flowing in the oil passages is supplied to the lower portion of the coil end via the guide portion. Additionally, the cooling oil flowing in the oil passages falls due to gravity and is supplied to the upper portion of the coil end, or other portions where no guide portion is provided. By providing the guide portion only in a range of 90 degrees to each side from the lowest point in the circumferential direction of the stator core (coil end), compared to providing it throughout the entire circumference of the stator core, the material used for the guide portion can be reduced, resulting in cost reduction. Therefore, cost reduction can be achieved while ensuring the supply of cooling oil to the lower portion of the coil end. Attached Figure Description
[0009] Figure 1 This is a simplified structural diagram of the motor unit 10 according to an embodiment of the present invention.
[0010] Figure 2 This is a simplified structural diagram of the modified motor unit 110.
[0011] Figure 3 This is a simplified structural diagram of the motor units 210 and 310 in the modified examples. Detailed Implementation
[0012] The embodiments (implementations) for carrying out this disclosure will be described with reference to the accompanying drawings. Figure 1 This is a simplified structural diagram of the motor unit 10 according to an embodiment of the present invention. Figure 1 (A) represents a cross-sectional view of motor unit 10. Figure 1 (B) represents the front view of motor unit 10. Figure 1 (A) is equivalent to Figure 1 (B) Cross-sectional view of motor unit 10 at section AA. Figure 1 (B) is equivalent to viewing from the right side. Figure 1 An external view of the motor unit 10 in (A). Furthermore, in Figure 1 In (B), the permanent magnet 18 of the rotor 14 and the motor housing 40 are omitted from the illustration. Additionally, in Figure 1 In (B), the coil end 26 and the guide portion 30 are shaded for ease of observation. The orientation (vertical direction) of the motor unit 10 is as follows: Figure 1 (A) and Figure 1 As shown in (B).
[0013] The motor unit 10 of the embodiment is mounted on electric vehicles, hybrid vehicles, fuel cell vehicles, etc., and includes a motor 12 configured as a synchronous generator motor, a guide section 30 used for guiding the cooling oil for cooling the motor 12, and a motor housing 40 for housing the motor 12 and the guide section 30. The motor 12 includes a rotor 14 fixed to the rotor shaft RS and a stator 20 that houses the rotor 14 in the center.
[0014] The rotor 14 has an annular rotor core 16 and permanent magnets 18 embedded at intervals in the circumferential direction of the rotor core 16. The rotor core 16 is fixed to a rotor shaft RS inserted into its inner side. The stator 20 has: a stator core 22 having an annular portion and a plurality of teeth protruding circumferentially at intervals from the inner circumference of the annular portion; and a stator coil 24 wound around a plurality of teeth of the stator core 22. The stator coil 24 has coil ends 25, 26 protruding from both sides of the stator core 22 in the axial direction. A plurality of oil passages 23, spaced circumferentially and axially penetrating within the stator core 22, are formed on the stator core 22 at a position on the outer circumferential side (radially outward) of the stator coil 24. In this embodiment, cooling oil is supplied from an oil pump to the coil end 25 via an oil passage and a guide (both omitted from the diagram), and is also supplied from the coil end 25 side of the stator core 22 axially to a plurality of oil passages 23 (see reference). Figure 1 (A) is indicated by the thicker arrow pointing to the left of the stator core 22. This guide portion is, for example, made of resin and shaped to cover the coil end 25 around its entire circumference. Cooling oil is supplied to the coil end 25, which can be cooled. Furthermore, by circulating cooling oil in multiple oil passages 23, the axial portions of the stator core 22 and the stator coil 24 that do not protrude from the stator core 22 can be cooled.
[0015] A guide portion 30 is disposed on the coil end 26 side of the stator core 22 in the axial direction, for storing or guiding cooling oil flowing in a portion of the plurality of oil passages 23 to the coil end 26. The guide portion 30 is, for example, made of resin. The guide portion 30 can be fixed to the end face of the coil end 26 side of the stator core 22 in the axial direction, or it can be fixed to the motor housing 40 in a manner that abuts against the end face. The guide portion 30 is disposed in such a manner that it extends circumferentially from the lowest end (lower end in the vertical direction) of the stator core 22 to both sides in a range of 90 degrees (the lower half range) in the circumferential direction. The guide portion 30 has: a first wall portion 31 located on the outer periphery side of the plurality of oil passages 23 of the stator core 22, and extending along the axial and circumferential directions of the stator core 22; and a second wall portion 32 extending inwardly from the front end (the end opposite to the stator core 22) in the axial direction of the first wall portion 31. The axial length of the first wall portion 31 is longer than the axial length of the coil end 26. Therefore, the guide portion 30 protrudes further axially outward (away from the stator core 22) than the coil end 26. The inner diameter of the second wall portion 32 can be smaller than or equal to the outer diameter of the coil end 26.
[0016] Through such a guide 30, cooling oil flowing in the oil passages 23 located in the generally lower half of the stator core 22 among the multiple oil passages 23 is stored in the guide 30, or flows along the second wall portion 32 of the guide 30 toward the inner circumference to be supplied to the coil end 26 (see reference). Figure 1 (A) is indicated by a thick arrow pointing to the right of the stator core 22 and below the rotor shaft RS. Additionally, cooling oil flows out of the guide portion 30 from the gap between the coil end 26 and the guide portion 30 (second wall portion 32). Furthermore, cooling oil flowing through the oil passages 23 located in the upper portion of the stator core 22, which are among the multiple oil passages 23, falls due to gravity and is supplied to the coil end 26 (see reference). Figure 1 (A) is indicated by the thick arrow pointing to the right of the stator core 22 and above the rotor shaft RS. Therefore, if the guide portion 30 is provided in the lower half of the circumferential direction of the stator core 22, the coil end 26 can be cooled to some extent throughout the entire circumference, even if it is not provided throughout the entire circumference. In addition, by providing the guide portion 30 only in the lower half of the circumferential direction of the stator core 22, the material used for the guide portion 30 can be reduced compared to the case where it is provided throughout the entire circumference, thus reducing costs. Based on the above, in the motor unit 10, cost reduction can be achieved while ensuring the supply of cooling oil to the lower part of the coil end 26.
[0017] In the motor unit 10 (cooling structure of motor 12) of the embodiment described above, a guide portion 30 is provided. This guide portion 30 is disposed on the coil end 26 side in the axial direction of the stator core 22 and guides cooling oil flowing in a portion of the oil passage 23 to the coil end 26. The guide portion 30 is configured to extend circumferentially from the lowermost end of the stator core 22 to both sides, which is radially outward from the outer periphery of the coil end 26. Thus, cooling oil flowing in the oil passage 23 is supplied to the lower portion of the coil end 26 through the guide portion 30. In addition, the cooling oil flowing in the oil passage 23 falls down due to gravity and is supplied to the upper portion of the coil end 26 and other portions where the guide portion 30 is not provided. By providing the guide portion 30 only in a range of 90 degrees to both sides from the lowermost end of the stator core 22 (coil end 26) in the circumferential direction, compared to providing it on the entire circumference of the stator core 22, the material used for the guide portion 30 can be reduced, thereby reducing costs. Therefore, in the motor unit 10, it is possible to reduce costs while ensuring the supply of cooling oil to the lower portion of the coil end 26.
[0018] In the above-described embodiment, the guide portion 30 of the motor unit 10 protrudes axially outward (towards the side away from the stator core 22) from the coil end 26, but is not limited to this. Figure 2 This is a simplified structural diagram of the modified motor unit 110. Figure 2 (A) and Figure 2 (B) corresponds to Figure 1 (A) and Figure 1 (B). In Figure 2 In the motor unit 110, a guide portion 130 is used instead of the guide portion 30 of the motor unit 10. The guide portion 130 has a first wall portion 131 and a second wall portion 132, which differ from the first wall portion 31 and the second wall portion 32 of the guide portion 30 in the following aspects: The axial length of the first wall portion 131 is shorter than the axial length of the coil end 26. Therefore, the guide portion 130 does not protrude axially outward from the coil end 26. The inner circumference of the second wall portion 132 abuts against the outer circumference of the coil end 26, and a plurality of cuts 133 are formed circumferentially spaced along the inner circumferential side of the second wall portion 132.
[0019] Cooling oil flowing in a portion of the oil passage 23 (the oil passage 23 provided in the lower half of the stator core 22) is stored in the guide portion 130 or supplied to the coil end 26. In supplying the coil end 26, for example, it flows along the second wall portion 132 towards the inner periphery and is supplied to the portion of the coil end 26 on the stator core 22 side (the gap with the end face of the stator core 22, etc.), or it flows axially through the cut 133 to the outer periphery of the coil end 26. This achieves the same effect as the motor unit 10 (the cooling structure of the motor 12).
[0020] In the above-described embodiments, the guide portions 30 and 130 of the motor units 10 and 110 are configured to extend circumferentially in a range of 90 degrees to both sides (the lower half of the range) from the lowest point (lower end in the vertical direction) of the stator core 22 in the circumferential direction, but are not limited to this, as long as they are formed in at least a portion of the range of 90 degrees to both sides from the lowest point (lower end in the vertical direction) of the stator core 22 in the circumferential direction. Figure 3 This is a simplified structural diagram of the motor units 210 and 310 in the modified examples. Figure 3 (A) indicates motor unit 210. Figure 3 (B) indicates motor unit 310. For example... Figure 3 As shown in motor unit 210 of (A), the guide portion 230 can also be configured to extend circumferentially within a range of approximately 45 degrees to each side from the lowest point of the stator core 22 in the circumferential direction. Figure 3 As shown in motor unit 310 of (B), the guide portion 330 may also be configured to extend circumferentially within a range of about 15 to 20 degrees to both sides from the lowest point of the stator core 22 in the circumferential direction.
[0021] In the above embodiments, the guide portions 30, 130, 230, and 330 of the motor units 10, 110, 210, and 310 are configured to extend circumferentially within a range of equal angles to each other from the lowest point of the stator core 22 in the circumferential direction. However, they can also be configured to extend circumferentially within a range of different angles to each other from the lowest point of the stator core 22 in the circumferential direction. For example, the guide portions can also be configured to extend circumferentially within a range of a first angle (e.g., a few degrees) to one side and a second angle (e.g., about 45 degrees) to the other side from the lowest point of the stator core 22 in the circumferential direction.
[0022] In the above embodiments, although not specifically described, cooling oil can be supplied by applying a certain degree of pressure to the multiple oil passages 23 from the coil end 25 side on the axial direction of the stator core 22. In this way, it is easy to increase the amount of cooling oil supplied to the coil end 26 that flows in a portion of the oil passages 23 and flows inward along the second wall portion 32 of the guide member 30 to the inner circumference.
[0023] The correspondence between the main elements of the implementation method and the main elements of the technical solution recorded in the content column of the utility model is explained. In the implementation method, stator core 22 is equivalent to "stator core", coil end 26 is equivalent to "coil end", stator coil 24 is equivalent to "stator coil", stator 20 is equivalent to "stator", motor 12 is equivalent to "motor", multiple oil passages 23 are equivalent to "multiple oil passages", and guide part 30 is equivalent to "guide part".
[0024] Furthermore, the correspondence between the main elements of the implementation method and the main elements of the technical solution described in the utility model content column is merely an example of how the implementation method is used to carry out the technical solution described in the utility model content column, and therefore does not limit the elements of the technical solution described in the utility model content column. That is, the interpretation of the technical solution described in the utility model content column should be based on the description in that column, and the implementation method is merely a specific example of the technical solution described in the utility model content column.
[0025] The above describes the methods for implementing this disclosure using the embodiments, but this disclosure is not limited to such embodiments in any way, and can of course be implemented in various ways without departing from the spirit of this disclosure.
[0026] [Industrial Applicability]
[0027] This disclosure can be used in industries such as the manufacturing of motor cooling structures.
[0028] Explanation of reference numerals in the attached figures
[0029] 10, 110, 210, 310… Motor unit; 12… Motor; 14… Rotor; 16… Rotor core; 18… Permanent magnet; 20… Stator; 22… Stator core; 23… Oil passage; 24… Stator coil; 25… Coil end; 26… Coil end; 30, 130, 230, 330… Guide section; 31, 131… First wall section; 32, 132… Second wall section; 40… Motor housing.
Claims
1. A cooling structure for a motor, the motor comprising a stator having: an annular stator core; and stator coils wound around the stator core, and having coil ends projecting axially from both sides of the stator core, wherein, The motor's cooling system includes: Multiple oil passages are formed circumferentially and spaced apart from each other in the stator core, and respectively penetrate the stator core axially; and A guide section is disposed at one end of the stator core along the axial direction, and guides the cooling oil flowing in a portion of the plurality of oil passages to the coil end. The guide portion is configured to extend along the circumferential direction only in a portion of the portion extending 90 degrees to both sides from the lowest point of the circumferential direction to the outer periphery of the coil end.