Rotor assembly, motor and vehicle

Abstract

This application provides a rotor assembly, a motor, and a vehicle. The rotor assembly includes a shaft and an iron core. The shaft has a cavity, and its outer wall has several arc segments and several transition segments, each transition segment connecting adjacent arc segments. Along the radial direction of the shaft, the distance between the transition segment and the centerline of the shaft is less than the radius of the arc segment. The transition segment also has a guide hole that connects to the cavity. The iron core is fitted onto the shaft. The inner wall of the iron core includes a first part and a second part. The first part abuts against the arc segments, and the second part forms a guide space with the transition segments; the guide space connects to the guide hole. In this way, cooling oil can flow directly from the guide hole through the cavity of the shaft into the guide space between the transition segment and the inner wall of the iron core, reducing the thermal resistance between the shaft and the iron core. The oil path is simple, allowing the cooling oil to fully contact the iron core, effectively improving the heat dissipation area and efficiency.

Description

Technical Field

[0001] This application relates to the field of vehicle technology, and more specifically, to rotor assemblies, motors, and vehicles. Background Technology

[0002] With the increasing popularity of new energy vehicles, the market demand for the performance of electric vehicle power systems is constantly rising. The required volumetric and mass power density of electric drive systems is also increasing. The greater the power of the drive motor, the higher the requirements for its heat dissipation capacity. Traditional water-cooling solutions cannot directly cool the heat source, leading to temperature buildup and the formation of localized hot spots. Therefore, direct cooling of the heat source is needed to improve cooling efficiency. Oil, due to its non-magnetic and non-conductive properties, has no impact on the motor's magnetic circuit, and the reducer itself contains a large amount of lubricating and cooling oil. Therefore, choosing cooling oil as the direct internal cooling medium has become a development trend for new energy electric drive systems.

[0003] However, the oil circuit in the existing motor rotor is complex, and the iron core, the main heat source of the motor rotor, cannot be adequately cooled, affecting the motor's working performance. Summary of the Invention

[0004] This application provides a rotor assembly, a motor, and a vehicle to solve the aforementioned technical problems.

[0005] The embodiments of this application are implemented as follows: A rotor assembly includes a shaft and an iron core. The shaft has a cavity, and its outer side wall has several arc segments and several transition segments, each transition segment connecting adjacent arc segments. Along the radial direction of the shaft, the distance between the transition segment and the centerline of the shaft is less than the radius of the arc segment. The transition segment also has a guide hole communicating with the cavity. The iron core is fitted onto the shaft, and its inner wall includes a first part and a second part. The first part abuts against the arc segments, and the second part forms a guide space with the transition segments; the guide space communicates with the guide hole.

[0006] In this way, the cooling oil can flow directly from the guide hole through the cavity of the shaft into the guide space between the transition section and the inner wall of the iron core, reducing the thermal resistance between the shaft and the iron core. The oil circuit is simple, allowing the cooling oil to fully contact the iron core, effectively improving the heat dissipation area and efficiency, which in turn helps to improve the motor's working performance.

[0007] In one possible implementation: the iron core is provided with a weight reduction groove, the weight reduction groove has an opening, the opening is located on the inner wall of the iron core and is adjacent to the second part, and the flow guiding space is connected to the opening.

[0008] In one possible implementation: a plurality of first portions are correspondingly arranged with a plurality of arc segments, wherein the central angle of each first portion is less than or equal to the central angle of the arc segment. A plurality of second portions are correspondingly arranged with a plurality of transition segments, wherein the central angle of each second portion is less than the central angle of the transition segment.

[0009] In one possible implementation: the second part has a first end, a second end, and an arcuate surface. Along the radial direction of the rotation axis, the arcuate surface is spaced apart from the transition section, and a flow guiding space is formed between the arcuate surface and the transition section; at least one of the first end and the second end is spaced apart from the transition section and forms a flow guiding orifice, the opening of which communicates with the flow guiding orifice.

[0010] In one possible implementation: a plurality of weight-reducing slots are spaced apart around the inner wall of the iron core. Each weight-reducing slot includes a first side, a second side, a third side, and a fourth side. One end of the first side intersects with one end of the second side, the other end of the first side connects to the third side, and the other end of the second side connects to the fourth side. The opening is located between the third and fourth sides. The iron core is also provided with magnetic slots, at least some of which are located between adjacent weight-reducing slots and are spaced apart from each other along the radial direction of the iron core.

[0011] In one possible implementation: the rotor assembly further includes a balance disc, which is sleeved on the shaft and abuts against the iron core along the axial direction of the shaft. A groove is provided on the side of the balance disc facing the iron core, and the groove connects to a flow guiding space. The balance disc also has a through hole connecting the groove and the space on the side of the balance disc facing away from the iron core.

[0012] In one possible implementation: the through hole has a first port and a second port, the first port communicating with the groove, and the second port located on the side of the balance disc opposite to the groove. Along the radial direction of the shaft, the distance between the first port and the centerline of the shaft is less than the distance between the second port and the centerline of the shaft.

[0013] In one possible implementation: along the axial direction of the shaft, the projection of the groove on the iron core at least partially overlaps with the projection of the flow space.

[0014] Embodiments of this application also provide an electric motor, including a housing, a stator, and a rotor assembly as described in the above embodiments, wherein the stator and the rotor assembly are assembled within the housing.

[0015] Embodiments of this application also provide a vehicle, including a body and a motor as described in the above embodiments, the motor being mounted on the body.

[0016] In the rotor assembly, motor, and vehicle of this application, the cooling oil can be directly stored through the guide hole in the cavity of the shaft into the guide space between the iron core and the shaft transition section, and then sprayed to the outside through the balance disc. This allows for the cooling of external structures (such as stator windings). The oil circuit is simple, without backflow, reducing adverse conditions such as insufficient oil filling and increased flow resistance. Furthermore, the direct injection of cooling oil into the space between the shaft and the iron core reduces the thermal resistance between the shaft and the iron core. Without affecting the magnetic field and strength, the iron core structure can be minimized, allowing the oil to fully contact the iron core, thereby increasing the heat dissipation contact area and significantly improving heat dissipation capacity. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the rotor assembly according to an embodiment of this application.

[0019] Figure 2 for Figure 1 The diagram shows an exploded view of the rotor assembly.

[0020] Figure 3 for Figure 1 The diagram shows a cross-sectional view of the rotor assembly.

[0021] Figure 4 for Figure 1 A partial cross-sectional view of the rotor shaft in the rotor assembly shown.

[0022] Figure 5 for Figure 1 The diagram shows a cross-sectional view of the rotor shaft in another direction within the rotor assembly.

[0023] Figure 6 for Figure 1 The diagram shows a planar structure of the iron core in the rotor assembly.

[0024] Figure 7 for Figure 1 The diagram shows a cross-sectional view of the rotor assembly.

[0025] Figure 8 for Figure 1 The diagram shows the structure of the balance disc in the rotor assembly.

[0026] Figure 9 for Figure 1 A partial cross-sectional structural schematic diagram of the rotor assembly shown.

[0027] Figure 10 This is a schematic diagram of the structure of a motor according to an embodiment of this application.

[0028] Figure 11 This is a schematic diagram of the structure of a vehicle according to an embodiment of this application.

[0029] Explanation of key component symbols: Rotor assembly 100; Shaft 10; Cavity 11; Arc segment 12; Transition segment 13; Guide hole 14; Main body 15; First assembly section 16; Second assembly section 17; Flange 171; Liquid inlet 172; Iron core 20; Inner wall 21; First part 211; Second part 212; First end 2121; Second end 2122; Arc surface 2123; Weight reduction groove 22; First side 221; Second side 222; Third side 223; Fourth side 224; Opening 225; Magnet groove 23; Guide space 30; Guide hole 31; Magnet 40; Balance disc 50; Groove 51; Sub-groove 511; Through hole 52; First port 521; Second port 522; Mating hole 53; Seal 60; Motor 200; Housing 201; Stator 202; Stator winding 2021; Vehicle 300; Body 301.

[0030] The following detailed description, in conjunction with the accompanying drawings, will further illustrate this application. Detailed Implementation

[0031] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0032] It should be noted that when a component is said to be "fixed to" another component, it can be directly on the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component. When a component is said to be "set on" another component, it can be directly set on the other component or there may be an intervening component. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "or / and" as used herein includes any and all combinations of one or more of the associated listed items.

[0034] Some embodiments of this application are described in detail. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0035] See Figures 1 to 7 This embodiment provides a rotor assembly 100, including a shaft 10 and an iron core 20. The shaft 10 has a cavity 11, and its outer side wall is provided with several arc segments 12 and several transition segments 13, each transition segment 13 connecting adjacent arc segments 12. Along the radial direction of the shaft 10, the distance D1 between the transition segment 13 and the centerline Z1 of the shaft 10 is less than the radius R1 of the arc segment 12. The transition segment 13 is also provided with a guide hole 14, which communicates with the cavity 11. The iron core 20 is sleeved on the shaft 10, and the inner wall 21 of the iron core 20 includes a first part 211 and a second part 212. The first part 211 abuts against the arc segment 12, and the second part 212 forms a guide space 30 with the transition segment 13; the guide space 30 communicates with the guide hole 14. Thus, when the cooling oil is injected into the cavity 11 of the rotating shaft 10, the cooling oil can flow directly from the guide hole 14 through the cavity 11 of the rotating shaft 10 into the guide space 30 between the transition section 13 and the inner wall 21 of the iron core 20, reducing the thermal resistance between the rotating shaft 10 and the iron core 20. Moreover, the oil circuit is simple, allowing the cooling oil to fully contact the iron core 20, effectively improving the heat dissipation area and heat dissipation efficiency, which in turn helps to improve the working performance of the motor 200.

[0036] In the embodiments of this application, such as Figure 1 , Figure 2 and Figure 3 As shown, the rotating shaft 10 may include a main body 15, a first assembly section 16, and a second assembly section 17. The first assembly section 16 and the second assembly section 17 are respectively connected to both ends of the main body 15 for connecting to an external rotating structure to allow the rotating shaft 10 to rotate. A cavity 11 extends from the first assembly section 16 to the second assembly section 17, and a liquid inlet 172 is provided at the end of the second assembly section 17 to inject cooling oil into the cavity 11. Several arc segments 12 and several transition sections 13 are provided on the outer wall of the main body 15. An iron core 20 is sleeved on the main body 15 and fixed relative to the main body 15 so that the iron core 20 can rotate synchronously with the rotating shaft 10.

[0037] In some embodiments, the first portion 211 of the inner wall 21 of the core 20 and the arc segment 12 can be elastically interference-fitted to keep the core 20 and the rotating shaft 10 relatively fixed, so that the core 20 does not detach or slide under high-speed rotation, or the displacement range of the core 20 is within a preset threshold. In other embodiments, the first portion 211 of the inner wall 21 of the core 20 can also be relatively fixed to the arc segment 12 through splines, snap-fit, connector positioning, or other means to meet assembly requirements; this application is not limited to this.

[0038] In some embodiments, such as Figure 4 As shown, the number of arc segments 12 and transition segments 13 are equal, and the arc segments 12 and transition segments 13 are alternately distributed along the circumference of the rotation axis 10, that is, each transition segment 13 connects to an adjacent arc segment 12. Furthermore, the arc segments 12 are distributed at equal intervals along the circumference of the rotation axis 10, and the transition segments 13 are also distributed at equal intervals along the circumference of the rotation axis 10, so that the rotation axis 10 is approximately centrally symmetrical, thereby improving the dynamic balance of the rotation axis 10.

[0039] In the embodiments of this application, the number of arc segments 12 and transition segments 13 are three each. This allows for the formation of sufficient heat dissipation and airflow space 30 between the rotating shaft 10 and the iron core 20, while also ensuring that the cross-section of the rotating shaft 10 is approximately triangular. This improves structural stability and simplifies the forming process of the rotating shaft 10, reducing manufacturing costs. In other embodiments, the number of arc segments 12 and transition segments 13 can be set to other quantities to meet design requirements; this application is not limited to this.

[0040] The rotating shaft 10 of this application can be manufactured by processes such as drawing and welding. In other embodiments, the rotating shaft 10 can also be manufactured by other processes such as casting and milling, but this application is not limited to this.

[0041] In some embodiments, a rounded corner structure is provided at the connection between adjacent arc segments 12 and transition segments 13 so that the arc segments 12 and transition segments 13 can transition smoothly, reduce stress concentration problems on the structure of the rotating shaft 10, and improve the structural reliability of the rotating shaft 10.

[0042] In some embodiments, such as Figure 5 and Figure 7 As shown, each transition section 13 can be provided with at least one guide hole 14, so that the cooling oil in the cavity 11 of the rotating shaft 10 can fully fill the guide space 30, which not only improves the heat dissipation effect, but also helps to reduce the problem of dynamic imbalance of the rotor assembly 100 caused by the oil not being filled or unevenly distributed.

[0043] Please refer to it again. Figure 1 and Figure 2 In the embodiments of this application, the core 20 may include multiple core laminations. These laminations are stacked and sleeved on the main body 15 of the rotating shaft 10, and the inner wall 21 of each lamination has a first portion 211 and a second portion 212. Along the axial direction of the rotating shaft 10, the first portions 211 and second portions 212 of the multiple core laminations are approximately aligned; an alignment error within 5% can be considered as alignment. This allows the flow-guiding space 30 formed between each core lamination and the transition section 13 to communicate along the axial direction of the rotating shaft 10, enabling the cooling oil to flow smoothly through the entire core 20, further reducing the problem of insufficient oil filling and improving heat dissipation.

[0044] Please see Figure 6 and Figure 7 In some embodiments, the iron core 20 is provided with a weight-reducing groove 22, which has an opening 225 located on the inner wall 21 of the iron core 20 and adjacent to the second part 212. The flow guiding space 30 communicates with the opening 225. In this way, the weight-reducing groove 22 and the flow guiding space 30 can together form an oil storage cavity, further increasing the contact area between the cooling oil and the iron core 20, improving heat dissipation efficiency, and reducing the material and weight of the iron core 20 while reducing the thermal resistance of the iron core 20, thereby optimizing the working performance of the motor 200.

[0045] In the embodiments of this application, a plurality of weight-reducing grooves 22 are spaced apart around the inner wall 21 of the iron core 20, and the plurality of weight-reducing grooves 22 are generally evenly distributed on the inner wall 21 of the iron core 20, so that the iron core 20 also presents a symmetrical structure to improve dynamic balance performance. The first part 211 and the second part 212 of the inner wall 21 of the iron core 20 are alternately distributed between the openings 225 of adjacent weight-reducing grooves 22, so that each weight-reducing groove 22 can communicate with the guide space 30, allowing the cooling oil to fully contact the iron core 20.

[0046] In one embodiment, the number of weight-reducing slots 22 is six. In other embodiments, the number of weight-reducing slots 22 can also be set to other numbers. The weight of the iron core 20 can be reduced as much as possible while ensuring the magnetic field performance and structural strength of the iron core 20. This application is not limited to this.

[0047] Please see Figure 7 In some embodiments, a plurality of first portions 211 are correspondingly arranged with a plurality of arc segments 12. Specifically, along the radial direction of the rotating shaft 10, the projection of each first portion 211 onto the outer wall of the rotating shaft 10 falls within the range of an arc segment 12. The central angle of each first portion 211 is less than or equal to the central angle of the arc segment 12. Thus, when the first portion 211 and the arc segment 12 are interference-fitted, the first portion 211 of the inner wall 21 of the core 20 can fully contact the arc segment 12, improving the connection strength and enhancing the connection stability between the core 20 and the rotating shaft 10. A plurality of second portions 212 are correspondingly arranged with a plurality of transition segments 13. Specifically, along the radial direction of the rotating shaft 10, the projection of each second portion 212 onto the outer wall of the rotating shaft 10 falls within the range of a transition segment 13. The central angle of each second portion 212 is less than the central angle of the transition segment 13. In this way, the risk of the second part 212 coming into contact with the arc segment 12 can be reduced, allowing the guide space 30 to form a structure with gaps on the side, which facilitates communication with the weight reduction groove 22, allowing the cooling oil to fully fill the weight reduction groove 22.

[0048] In some implementations, such as Figure 7As shown, the second part 212 has a first end 2121, a second end 2122, and an arcuate surface 2123. Along the radial direction of the rotating shaft 10, the arcuate surface 2123 is spaced apart from the transition section 13, and a flow guiding space 30 is formed between the arcuate surface 2123 and the transition section 13. At least one of the first end 2121 and the second end 2122 is spaced apart from the transition section 13 and forms a flow guiding orifice 31, and the opening 225 communicates with the flow guiding orifice 31.

[0049] In some embodiments, the first end 2121 and the second end 2122 can be spaced apart from the transition section 13, so that both sides of the flow guiding space 30 form flow guiding holes 31, which facilitates the connection between the adjacent weight reduction grooves 22 at both ends of the second part 212. This is beneficial to increase the number of weight reduction grooves 22, reduce the weight and cost of the iron core 20, and also increase the heat dissipation area.

[0050] In other embodiments, the first end 2121 and the second end 2122 may be one of them spaced apart from the transition section 13, so that a flow guiding orifice 31 is formed on one side of the flow guiding space 30. The weight reduction groove 22 is located at the end of the second part 212 spaced apart from the transition section 13, so that the opening 225 of the weight reduction groove 22 connects to the flow guiding orifice 31. In this case, the number of weight reduction grooves 22 can be reduced, which is beneficial to improving the structural strength of the iron core 20.

[0051] Please refer to it again. Figure 6 and Figure 7 In some embodiments, a plurality of weight-reducing grooves 22 are spaced apart around the inner wall 21 of the iron core 20. Each weight-reducing groove 22 includes a first side 221, a second side 222, a third side 223, and a fourth side 224. One end of the first side 221 intersects with one end of the second side 222, the other end of the first side 221 connects to the third side 223, and the other end of the second side 222 connects to the fourth side 224. An opening 225 is located between the third side 223 and the fourth side 224. The iron core 20 is also provided with magnetic grooves 23, at least some of which are located between adjacent weight-reducing grooves 22. The magnetic grooves 23 are used to fill magnets 40. The heat generated by the magnets 40 is conducted to the cooling oil through the iron core 20 material between the magnetic grooves 23 and the weight-reducing grooves 22. In this way, the weight reduction groove 22 can roughly form a rhomboid structure with an opening 225 at one end, which is conducive to extending the weight reduction groove 22 to the outer ring of the iron core 20, increasing the heat dissipation area between the cooling oil and the iron core 20. At the same time, the heat generated by the magnet 40 filled in the magnet groove 23 can be quickly conducted to the cooling oil in the weight reduction groove 22, which is conducive to reducing local hot spots.

[0052] In the embodiments of this application, the magnet groove 23 is generally V-shaped to match the shape of the weight-reducing groove 22, which helps to increase the heat dissipation area, reduce thermal resistance, and improve heat dissipation efficiency. In other embodiments, the magnet groove 23 can also be U-shaped, N-shaped, W-shaped, etc., as long as the design requirements are met, and this application is not limited to this.

[0053] Furthermore, along the circumferential direction of the iron core 20, several magnetic slots 23 are also evenly distributed to maintain the symmetrical structure of the iron core 20 and reduce dynamic imbalance problems.

[0054] Please see Figure 1 , Figure 2 , Figure 3 and Figure 8 In some embodiments, the rotor assembly 100 further includes a balance disc 50, which is sleeved on the shaft 10 and abuts against the core 20 along the axial direction of the shaft 10. A groove 51 is provided on the side of the balance disc 50 facing the core 20, and the groove 51 connects to the flow guide space 30. The balance disc 50 also has a through hole 52, which connects the groove 51 and the space on the side of the balance disc 50 away from the core 20. Thus, the cooling oil in the flow guide space 30 can flow out through the groove 51 and the through hole 52 to the space on the side of the balance disc 50 away from the core 20, which can be used to cool the external structure of the rotor, such as the stator 202 and stator winding 2021, thereby further improving the heat dissipation effect of the motor 200 and optimizing the working performance of the motor 200.

[0055] In the embodiments of this application, a mating hole 53 is provided in the middle of the balance disc 50, and the main body 15 of the rotating shaft 10 passes through the mating hole 53. The shape of the mating hole 53 is adapted to the shape of the arc segment 12 and the transition segment 13 of the outer wall of the main body 15, so that when the balance disc 50 is sleeved on the rotating shaft 10, it can remain relatively fixed with the rotating shaft 10. The groove 51 on the side of the balance disc 50 facing the iron core 20 is arranged around the mating hole 53. The cooling oil flowing out of the guide space 30 can be temporarily stored in the groove 51, and then flow out from the through hole 52 to the external space. The flowing cooling oil can generate centrifugal motion during the rotation of the rotor assembly 100, so that the oil can fully wet and cool the external structure.

[0056] In some embodiments, such as Figure 8 As shown, a number of through holes 52 can be spaced apart on the periphery of the groove 51, which helps to increase the outflow of cooling oil and improve the flow rate of cooling oil inside the rotor assembly 100, thereby improving heat dissipation efficiency. At the same time, it also allows the cooling oil flowing out to the external space to quickly contact or wet external heat sources, comprehensively improving the overall heat dissipation performance of the motor 200. Furthermore, the number of through holes 52 can also be evenly distributed on the periphery of the groove 51 to make the balance disc 50 form a symmetrical structure, reducing the dynamic imbalance problem of the rotor assembly 100.

[0057] In some embodiments, along the radial direction of the balance disc 50, a sub-groove 511 is provided on the side of the groove 51 away from the mating groove, and a through hole 52 is provided in the sub-groove 511. In this way, when the rotor assembly 100 rotates, the cooling oil in the groove 51 can flow into the through hole 52 in a directional manner through the guide of the sub-groove 511, thereby improving the efficiency of the oil flowing out of the through hole 52.

[0058] Please see Figure 9 In some embodiments, the through hole 52 has a first port 521 and a second port 522. The first port 521 communicates with the groove 51, and the second port 522 is located on the side of the balance disc 50 opposite to the groove 51. Along the radial direction of the shaft 10, the distance L1 between the first port 521 and the center line Z1 of the shaft 10 is less than the distance L2 between the second port 522 and the center line Z1 of the shaft 10. Thus, the extension direction of the through hole 52 can be inclined outward relative to the center line Z1 of the shaft 10, which facilitates the flow of oil to an external heat source (such as the stator winding 2021) through centrifugal motion.

[0059] In some embodiments, the projection of the groove 51 onto the iron core 20 at least partially overlaps with the projection of the flow guide space 30 along the axial direction of the shaft 10. Thus, the groove 51 can directly connect to the flow guide space 30 in the axial direction of the shaft 10, allowing cooling oil to be quickly injected into the groove 51.

[0060] In some embodiments, along the axial direction of the rotating shaft 10, the projection of the groove 51 onto the iron core 20 may at least partially overlap with the projection of the weight-reducing groove 22. In this way, the cooling oil in the weight-reducing groove 22 can also flow into the groove 51 along the axial direction of the rotating shaft 10, which helps to increase the flow rate of the cooling oil and improve heat dissipation efficiency.

[0061] In some embodiments, the number of balance discs 50 can be two. Along the axial direction of the shaft 10, the two balance discs 50 are respectively disposed at opposite ends of the iron core 20, so that the cooling oil in the guide space 30 can flow out from the balance discs 50 at both ends of the iron core 20, which facilitates heat dissipation and cooling of multiple heat sources outside the rotor assembly 100.

[0062] Figure 9 The dashed arrows represent partial examples of the cooling oil flow path and are not intended to limit the specific oil path in the rotor assembly 100 of this application.

[0063] Please refer to it again. Figure 1 , Figure 2 and Figure 3In some embodiments, the rotor assembly 100 further includes a seal 60, which is sleeved on the first connecting section of the shaft 10. The seal 60 abuts against the side of a balance disc 50 away from the iron core 20, serving both to position the balance disc 50 and to seal the gap at the connection between the balance disc 50 and the shaft 10, thereby reducing oil leakage.

[0064] The second connecting section of the rotating shaft 10 is also provided with a flange 171, which is located at one end of the second connecting section near the main body 15. The flange 171 is used to abut against the side of the other balance disc 50 opposite to the iron core 20, and can also serve the functions of positioning and sealing. In the embodiments of this application, the flange 171 includes, but is not limited to, structures such as shaft shoulders, as long as they meet the assembly requirements.

[0065] Please see Figure 10 This application also provides an electric motor 200, including a housing 201, a stator 202, and a rotor assembly 100 as described in the above embodiments. The stator 202 and the rotor assembly 100 are assembled within the housing 201. The stator winding 2021 at the end of the stator 202 can correspond to the position of the balance disc 50 in the rotor assembly 100. Oil flowing out from the through holes 52 on the balance disc 50 can be sprayed onto the stator winding 2021, improving the overall heat dissipation performance of the motor 200.

[0066] Please see Figure 11 The embodiments of this application also provide a vehicle 300, including a body 301 and a motor 200 as described in the above embodiments, the motor 200 being mounted on the body 301.

[0067] In this application, the rotor assembly 100, motor 200, and vehicle 300 all utilize cooling oil. The oil flows into the cavity 11 through the inlet 172 at the end of the second connecting section of the shaft 10, and then directly into the guide space 30 between the iron core 20 and the transition section 13 of the shaft 10 through the guide hole 14. It is then sprayed to the outside through the balance disc 50, effectively cooling external structures (such as the stator winding 2021). The oil path is simple, without backflow, reducing the risk of insufficient oil coverage or increased flow resistance. Furthermore, the direct injection of cooling oil into the space between the shaft 10 and the iron core 20 reduces thermal resistance between them. Without affecting the magnetic field and its strength, the iron core 20 structure can be minimized, allowing for sufficient contact between the oil and the iron core 20, thereby increasing the heat dissipation contact area and significantly improving heat dissipation capacity. In addition, this application uses less material for the iron core 20, has a simple structure for the balance disc 50, and a simple molding process for the shaft 10, resulting in significant cost reduction.

[0068] The above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to the above preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions to the technical solutions of this application should not depart from the spirit and scope of the technical solutions of this application.

Claims

1. A rotor assembly, characterized in that, include: A rotating shaft has a cavity. The outer wall of the rotating shaft is provided with several arc segments and several transition segments, and each transition segment is connected between adjacent arc segments. Along the radial direction of the rotating shaft, the distance between the transition segment and the centerline of the rotating shaft is less than the radius of the arc segment. The transition segment is also provided with a guide hole, and the guide hole communicates with the cavity. An iron core is fitted onto the rotating shaft. The inner wall of the iron core includes a first part and a second part. The first part abuts against the arc segment, and the second part forms a flow guiding space with the transition segment. The flow guiding space is connected to the flow guiding hole.

2. The rotor assembly according to claim 1, characterized in that: The iron core is provided with a weight reduction groove, the weight reduction groove has an opening, the opening is located on the inner wall of the iron core and is adjacent to the second part, and the flow guiding space is connected to the opening.

3. The rotor assembly according to claim 1, characterized in that: A plurality of first portions are provided corresponding to a plurality of arc segments, wherein the central angle of each first portion is less than or equal to the central angle of the arc segment; A plurality of second portions are provided corresponding to a plurality of transition segments, wherein the central angle of each second portion is smaller than the central angle of the transition segment.

4. The rotor assembly according to claim 2, characterized in that: The second part has a first end, a second end, and an arcuate surface. Along the radial direction of the rotating shaft, the arcuate surface is spaced apart from the transition section, and the flow guiding space is formed between the arcuate surface and the transition section. At least one of the first end and the second end is spaced apart from the transition section and forms a flow guiding orifice. The opening communicates with the flow guiding orifice.

5. The rotor assembly according to claim 2, characterized in that: Several weight-reducing grooves are spaced apart around the inner wall of the iron core. Each weight-reducing groove includes a first side, a second side, a third side, and a fourth side. One end of the first side intersects with one end of the second side, the other end of the first side is connected to the third side, the other end of the second side is connected to the fourth side, and the opening is located between the third side and the fourth side. The iron core is also provided with magnetic steel grooves, at least some of which are located between adjacent weight-reducing grooves, and the magnetic steel grooves and weight-reducing grooves are spaced apart along the radial direction of the iron core.

6. The rotor assembly according to claim 1, characterized in that, Also includes: A balance disc is sleeved on the rotating shaft, and the balance disc abuts against the iron core along the axial direction of the rotating shaft; the balance disc has a groove on the side facing the iron core, and the groove communicates with the flow guiding space; the balance disc also has a through hole, and the through hole communicates the groove and the space on the side of the balance disc away from the iron core.

7. The rotor assembly according to claim 6, characterized in that: The through hole has a first port and a second port, the first port being connected to the groove, and the second port being located on the side of the balance disc away from the iron core; Along the radial direction of the rotating shaft, the distance between the first port and the centerline of the rotating shaft is less than the distance between the second port and the centerline of the rotating shaft.

8. The rotor assembly according to claim 6, characterized in that: Along the axial direction of the rotating shaft, the projection of the groove on the iron core at least partially overlaps with the projection of the flow guiding space.

9. An electric motor, characterized in that, It includes a housing, a stator, and a rotor assembly as described in any one of claims 1-8, wherein the stator and the rotor assembly are assembled within the housing.

10. A vehicle, characterized in that, It includes a vehicle body and the motor as described in claim 9, wherein the motor is mounted on the vehicle body.

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