Rotor assembly and driving motor

Abstract

The utility model relates to a rotor assembly and a driving motor. The rotor assembly comprises a rotor iron core, and the rotor iron core is provided with axially-through magnetic steel grooves. Magnetic steel and all side faces of the magnetic steel are coated with expansion materials, the magnetic steel is embedded into the magnetic steel grooves, the rotor core is heated so that the expansion materials can expand and the magnetic steel can be fixedly embedded into the magnetic steel grooves, after the expansion materials expand, oil way gaps are still reserved in the magnetic steel grooves, and the oil way gaps are formed in the magnetic steel grooves. And an axial oil channel is formed for cooling oil to pass through and directly cool the magnetic steel. The magnetic steel is fixed in the magnetic steel groove by coating the surface with the expansion material, so that stable connection between the magnetic steel and the magnetic steel groove is ensured, and compared with a fixing mode through transfer injection molding, the magnetic steel fixing structure has the advantages that after the magnetic steel is fixed, the expansion material does not need to fill the whole magnetic steel groove, and an axial oil channel for cooling oil to pass is still reserved in the magnetic steel groove; therefore, the magnetic steel can be directly cooled, the cooling speed of the magnetic steel is improved, and the working efficiency of the driving motor is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of motors, in particular to a rotor assembly and a driving motor. Background Art

[0002] With the continuous iteration of new energy vehicle electric drive technology, the requirements for the maximum speed and torque power density of the motor are also increasing. Among them, the operating temperature of the stator and rotor of the new energy vehicle drive motor, especially the operating temperature of the magnetic steel in the rotor, limits the improvement of the drive motor's working efficiency.

[0003] When the drive motor is running, the eddy current loss and hysteresis loss generated by the magnet will increase the temperature of the magnet. However, in the traditional drive motor's rotor heat dissipation solution, since the magnet is fixed in the magnet slot through a transfer molding process, it is necessary to additionally set up special oil channels on the rotor punchings to dissipate the heat of the rotor. Although it has a certain cooling effect on the rotor as a whole, the additional special oil channels prevent the cooling oil from directly cooling the magnet in the magnet slot, resulting in a slow cooling speed of the magnet, which limits the improvement of the drive motor's working efficiency.

[0004] In addition, since the overall cooling structure of the rotor requires the provision of special oil channels on the rotor punchings, the rotor punching structure is complicated, and the mold structure for producing the rotor punchings is also complicated, which not only increases the complexity of parts processing and poor processing performance, but also causes high production costs. Utility Model Content

[0005] In order to overcome the problems existing in the related art, the present disclosure provides a rotor assembly and a drive motor.

[0006] According to a first aspect of an embodiment of the present disclosure, the present disclosure provides a rotor assembly, comprising: a rotor core, the rotor core being provided with an axially through-going magnetic steel slot; a magnetic steel, all sides of which are coated with an expansion material, the magnetic steel being embedded in the magnetic steel slot, the rotor core being heated to expand the expansion material and to embed the magnetic steel in the magnetic steel slot, wherein after the expansion material expands, an oil path gap is still left in the magnetic steel slot to form an axial oil channel for cooling oil to pass through and directly cool the magnetic steel.

[0007] In some embodiments, the rotor assembly includes two balancing plates, which are respectively arranged at the axial ends of the rotor core, and the balancing plates are provided with a plurality of radial oil inlet channels arranged at intervals along the circumferential direction, wherein the inlet end of the radial oil inlet channel is located at the radial inner end surface of the balancing plate, and the outlet end of the radial oil inlet channel corresponds to the position of the axial oil channel formed in the magnetic steel groove.

[0008] In some embodiments, the radial oil inlet passages of the two balancing plates are staggered in the circumferential direction so that the cooling oil in the axial oil passages in at least two adjacent magnetic steel grooves flows in opposite directions.

[0009] In some embodiments, a plurality of branch oil passages are disposed at the outlet end of the radial oil inlet passage, and the number and positions of the branch oil passages correspond to the number and positions of the axial oil passages.

[0010] In some embodiments, the balancing plate further includes an oil outlet hole, which axially penetrates the balancing plate and corresponds to the axial oil passage formed by the magnetic steel groove.

[0011] In some embodiments, the rotor assembly also includes a hollow rotor shaft, and the rotor core and the balance plate of the rotor assembly are both torsionally sleeved on the outer wall of the rotor shaft, wherein the rotor shaft is provided with an oil guide port extending radially therethrough, and the oil guide port is aligned with an inlet end of the radial oil inlet channel of the balance plate.

[0012] In some embodiments, the radial oil inlet passage is located on a side of the balancing plate abutting against the rotor core.

[0013] In some embodiments, the rotor core further includes one or more channels other than the magnetic steel slots, and the rotor assembly is provided with two covering plates, which are respectively arranged at the axial ends of the rotor core for covering the channels.

[0014] In some embodiments, the rotor core is a lamination group formed by bonding multiple layers of metal laminations with an adhesive.

[0015] According to a second aspect of an embodiment of the present disclosure, the present disclosure provides a driving motor, comprising: a rotor assembly as described in the first aspect; and a stator assembly, wherein the stator assembly is sleeved on an outer wall of the rotor assembly, and the stator assembly is energized to generate a rotating magnetic field to drive the rotor assembly to rotate.

[0016] The technical solution provided by the embodiments of the present disclosure may include the following beneficial effects: the magnet is fixed in the magnet slot by coating the expansion material on the surface, which not only ensures the firm connection between the magnet and the magnet slot, but also, compared with the fixing method by transfer injection molding, the present disclosure enables the magnet to be fixed without the expansion material filling the entire magnet slot, so that an axial oil channel for cooling oil to pass through is still left in the magnet slot, thereby directly cooling the magnet, increasing the cooling rate of the magnet, and improving the working efficiency of the drive motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0018] Figure 1 is a perspective cross-sectional view of a rotor assembly according to an exemplary embodiment;

[0019] Figure 2 is a schematic structural diagram of a rotor core according to an exemplary embodiment;

[0020] Figure 3 is a schematic structural diagram of a balance board according to an exemplary embodiment;

[0021] Figure 4 A rotor core with other oil passages is shown according to an exemplary embodiment;

[0022] Figure 5 and Figure 6 They are schematic diagrams of structures in which cover plates are arranged at both axial ends of a rotor core according to an exemplary embodiment. DETAILED DESCRIPTION

[0023] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0024] According to an embodiment of the present invention, the rotor assembly is suitable for installation in a drive motor. In the present invention, unless otherwise specified, the axial direction, radial direction and circumferential direction refer to the axial direction, radial direction and circumferential direction of the rotor assembly respectively; the axial end refers to Figure 1 The left side of the axis is Figure 1 The term "torsionally resistant connection" refers to a connection between two components that does not rotate relative to each other, which can be achieved through a press fit (i.e., an interference fit) or by forming the two components as one piece. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0025] To solve the above technical problems, the present disclosure provides a rotor assembly 100. The rotor assembly 100 is used in a drive motor, and the drive motor is suitable for transportation vehicles such as new energy vehicles, trams, and subways. In this embodiment, the application of the drive motor in a new energy vehicle is taken as an example for further description.

[0026] like Figure 1 As shown, the rotor assembly 100 at least includes a rotor shaft 10 , a rotor core 20 , a magnetic steel 30 and a balancing plate 40 .

[0027] The interior of the rotor shaft 10 is hollow. In this embodiment, an axial through hole 11 may be provided inside the rotor shaft 10. In other embodiments, an axial blind hole may also be provided inside the rotor shaft 10, wherein the depth of the blind hole may be sufficient to reach the axial position of the rotor core 20 and the magnetic steel 30. The hollow structure of the rotor shaft 10 is intended to allow cooling oil to flow through, thereby cooling the rotor assembly 100.

[0028] The rotor core 20 and the balance plate 40 are both sleeved on the outside of the rotor shaft 10 in a torsion-resistant manner, which transmit the driving torque generated in the drive motor to the rotor shaft 10, thereby transmitting mechanical energy. The structure of the rotor core 20 is generally divided into two types, namely, laminated manufacturing and integral molding. The integral molding method is to directly punch the iron block into the corresponding shape and size, and then go through multiple process steps such as pressing, annealing, and grinding to form an integrally formed rotor core 20. In this embodiment, as Figure 1 , Figure 4 and Figure 5 As shown, the rotor core 20 is manufactured by a lamination process, usually using silicon steel sheets or nickel-iron alloy thin plates, and stacking multiple layers of iron sheets in order and bonding and fixing them with a suitable adhesive to finally form the rotor core 20 of the lamination group.

[0029] Furthermore, the rotor core 20 may be provided with a magnetic steel slot 21 that penetrates in the axial direction, and the magnetic steel slot 21 is used to install and fix the magnetic steel 30. In this embodiment, all sides or the entire surface of the magnetic steel 30 are coated with a layer of expansion material. Subsequently, the magnetic steel 30 with a layer of expansion material on the surface is embedded in the magnetic steel slot 21, and the rotor core 20 is heated to expand the expansion material due to the heat, thereby firmly embedding the magnetic steel 30 in the magnetic steel slot 21.

[0030] Specifically, the expansion material used may be a powdery structure in an initial state, and the expansion material may be an epoxy resin with an expansion factor added thereto, or the like.

[0031] First, an expansion material with a powder structure is evenly sprayed onto each surface of the magnetic steel 30 using an electrostatic spray gun, and then a pre-curing step is performed at room temperature or a relatively low temperature.

[0032] Secondly, the pre-cured magnetic steel 30 has a hardened expansion material attached to its surface. The magnetic steel 30 with the expansion material on its surface is inserted into the magnetic steel slot 21 of the rotor core 20. Then, the rotor core 20 with the magnetic steel 30 installed is heated as a whole until it reaches a preset higher temperature, and this temperature is kept constant for a period of time.

[0033] During this period, the epoxy resin material containing the expansion factor begins to expand significantly under the action of heat. Since the expansion material has thermal expansion effect and thermal bonding properties, the magnetic steel 30 can be tightly and firmly fixed inside the magnetic steel slot 21 under the action of the expansion material.

[0034] Among them, multiple groups of magnetic steel slots 21 can be set on the rotor core 20 to meet different needs. Figure 2 As shown, in this embodiment, the magnetic steel slot 21 can be divided into a first magnetic steel slot 211 and a second magnetic steel slot 212, and the first magnetic steel slot 211 and the second magnetic steel slot 212 are arranged in the radial direction R and maintain a certain radial spacing in the radial direction R. Among them, the first magnetic steel slot 211 group includes two magnetic steel slots 21, which can be arranged in a "V" shape in the circumferential direction, and the second magnetic steel slot 212 group includes one magnetic steel slot 21, which can be arranged in a "one" shape in the circumferential direction. In other embodiments, the second magnetic steel slot 212 group can also be in a "V" shape or other suitable layout forms. It is not specifically limited here.

[0035] Similarly, the magnetic steel 30 may also include multiple groups of magnetic steels 30 to match different magnetic steel slots 21. In the present embodiment, the magnetic steel 30 includes a first magnetic steel 31 and a second magnetic steel 32, and the first magnetic steel 31 and the second magnetic steel 32 are respectively embedded in the first magnetic steel slot 211 and the second magnetic steel slot 212. Among them, the thickness and length of the first magnetic steel 31 and the second magnetic steel 32 may be the same or different, and are not specifically limited here. By flexibly setting the size parameters of the first magnetic steel 31 and the second magnetic steel 32, the versatility and adaptability of the drive motor design are effectively taken into account.

[0036] It is further understood that the terms "first", "second", etc. are used to describe various structures, but these structures should not be limited to these terms. These terms are only used to distinguish structures of the same type from each other, and do not indicate a specific order or degree of importance. In fact, the expressions "first", "second", etc. can be used interchangeably. For example, without departing from the scope of the present disclosure, the first magnetic steel 31 can also be referred to as the second magnetic steel 32, and similarly, the second magnetic steel 32 can also be referred to as the first magnetic steel 31.

[0037] Furthermore, the size of the magnetic steel slot 21 is larger than the size of the magnetic steel 30 to ensure that the magnetic steel 30 can be smoothly inserted. Figure 2 As shown, in the length direction of the magnetic steel slot 21, there is extra space at both ends of the magnetic steel slot 21 relative to the length of the magnetic steel 30, so that after the magnetic steel 30 is inserted into the magnetic steel slot 21, a certain space is formed between the two ends of the magnetic steel slot 21 and the magnetic steel 30. In terms of thickness, the width of the middle part of the magnetic steel slot 21 and the thickness gap of the magnetic steel 30 are maintained at about 0.1 mm.

[0038] After the expansion material is heated and expanded, it will fill the gap between the inner wall of the magnetic steel slot 21 and the outer wall of the magnetic steel 30 in the thickness direction, so that the magnetic steel 30 can be firmly fixed inside the magnetic steel slot 21. However, even if the expansion material is heated and expanded, it will not completely fill the remaining space at both ends of the magnetic steel slot 21 in the length direction, so that gaps for cooling oil to flow are left at both ends of the magnetic steel slot 21, and multiple gaps are connected to form an axial oil passage 22 that runs through the rotor core 20 in the axial direction.

[0039] The cooling oil can flow directly along the axial oil passage 22 without obstruction, so that the cooling oil can directly act on the surface of the magnet 30, and the cooling oil can directly, quickly and effectively cool the magnet 30. During the operation of the drive motor, this efficient cooling method helps to ensure that the magnet 30 always maintains a suitable operating temperature, thereby effectively improving the overall working efficiency and operating stability of the drive motor.

[0040] Furthermore, if Figure 1 As shown, the rotor assembly 100 further includes two balancing plates 40 , the structures of the two balancing plates 40 may be the same, and the two balancing plates 40 are respectively disposed at the axial ends of the rotor core 20 , and may play a role in axially limiting the rotor core 20 .

[0041] like Figure 3 As shown, the middle part of the balancing plate 40 has a sleeve hole that can be sleeved on the outside of the rotor shaft 10. Among them, a plurality of radial oil inlet channels 41 are arranged at equal intervals along the circumferential direction on one side surface of the balancing plate 40. The radial oil inlet channels 41 arranged at equal intervals ensure the balance of the cooling oil circulation.

[0042] Among them, the inlet end 411 of the radial oil inlet channel 41 is located on the radial inner end surface of the balance plate 40, and correspondingly, the hollow rotor shaft 10 is provided with an oil guide port 12 that penetrates in the radial direction, and the oil guide port 12 is aligned with the inlet end 411 of the radial oil inlet channel 41 of the balance plate 40. Therefore, when the cooling oil inside the rotor shaft 10 is driven by centrifugal force, it can accurately pass through the oil guide port 12 and the inlet end 411 of the radial oil inlet channel 41 and smoothly flow into the radial oil inlet channel 41. The outlet end 412 of the radial oil inlet channel 41 corresponds to the position of the axial oil channel 22 formed in the magnetic steel slot 21. Finally, after the cooling oil is guided in the radial oil inlet channel 41, it can seamlessly pass through the outlet end 412 of the radial oil inlet channel 41 and directly enter the rotor core 20, and finally realize direct and efficient cooling of the magnetic steel 30 in the magnetic steel slot 21. In this way, not only the directional flow of the cooling oil is ensured, but also the cooling effect of the magnetic steel 30 is significantly improved, thereby helping to improve the overall operating efficiency and stability of the drive motor.

[0043] Furthermore, Figure 3As shown, the balancing plate 40 may further include an oil outlet hole 42, which axially penetrates the balancing plate 40 and corresponds to the axial oil passage 22 formed by the magnetic steel groove 21. In this way, when the cooling oil in the axial oil passage 22 of the magnetic steel groove 21 completes the cooling task of the magnetic steel 30 in the magnetic steel groove 21, it can be directly discharged through the oil outlet hole 42, forming a complete cooling cycle.

[0044] The flow path of the cooling oil throughout the cooling process will be described in detail below.

[0045] As the drive motor runs, the rotor shaft 10 generates centrifugal force, and the cooling oil stored in the rotor shaft 10 is thrown into the radial oil inlet 41 of the balance plate 40 located at one axial end of the rotor core 20 through the oil guide port 12. The cooling oil in the radial oil inlet 41 enters the axial oil channel 22 in the magnetic steel slot 21 of the rotor core 20 through the centrifugal force, and is in close contact with the magnetic steel 30 working at high temperature, which can quickly absorb heat and realize direct and efficient cooling of the magnetic steel 30. After cooling is completed, the cooling oil that has absorbed a large amount of heat is discharged from the oil outlet 42 of the balance plate 40 located at the other axial end of the rotor core 20, thereby releasing the absorbed heat and realizing the cooling cycle of the magnetic steel 30 in the rotor core 20.

[0046] In addition, radial oil inlet passages 41 and oil outlet holes 42 are provided in the same balancing plate 40, and the radial oil inlet passages 41 and the oil outlet holes 42 are arranged in a staggered arrangement in the circumferential direction, so that after the cooling oil enters the radial oil inlet passages 41, it can flow inside the rotor core 20 along a specific path to effectively cool the magnetic steel 30, and then be smoothly discharged through the circumferentially staggered oil outlet holes 42 in another balancing plate 40, forming a complete cooling circulation system.

[0047] In some embodiments, the outlet end 412 of the radial oil inlet passage 41 may be provided with a plurality of branch oil passages 413 , and the number and position layout of the branch oil passages 413 may correspond to the number and position layout of the axial oil passages 22 .

[0048] Specifically, Figure 3 As shown, both ends of each first magnetic steel groove 211 and the second magnetic steel groove 212 are formed with axial oil passages 22, so each first magnetic steel groove 211 and the second magnetic steel groove 212 can include two independent axial oil passages 22. In this embodiment, each radial oil inlet passage 41 corresponds to three magnetic steel grooves 21, namely, two first magnetic steel grooves 211 and one second magnetic steel groove 212, so six branch oil passages 413 can be set at the outlet end 412 of the radial oil inlet passage 41, and the end of each branch oil passage 413 accurately points to the entrance position of each axial oil passage 22, thereby ensuring that the cooling oil can accurately flow into the corresponding axial oil passage 22.

[0049] It should be noted that the number of branch oil channels 413 at the outlet end 412 of the above radial oil inlet channel 41 is only exemplary and is not intended to limit the scope of protection of the present disclosure. In some other embodiments, the number and position of the branch oil channels 413 depend on the number and position of the axial oil channels 22 formed in the magnetic steel groove 21.

[0050] In some embodiments, in the circumferential direction W, the radial oil inlet passages 41 of the two balancing plates 40 are staggered in the circumferential direction so that the cooling oil in the axial oil passages 22 in at least two adjacent magnetic steel grooves 21 flows in opposite directions.

[0051] Specifically, since the two balancing plates 40 have the same structure and both include radial oil inlet passages 41 and oil outlet holes 42 arranged crosswise in the circumferential direction, when installed with the rotor core 20, the two balancing plates 40 are staggered in the circumferential direction W, so that the radial oil inlet passage 41 of the balancing plate 40 located at one axial end of the rotor core 20 corresponds to the oil outlet hole 42 of the balancing plate 40 located at the other axial end of the rotor core 20, and at the same time, the radial oil inlet passage 41 of the balancing plate 40 located at the other axial end of the rotor core 20 corresponds to the oil outlet hole 42 of the balancing plate 40 located at the other axial end of the rotor core 20. It can be seen that two circles of axially spaced oil guide ports 12 can be set on the rotor shaft 10 in the axial direction A, and one circle can include multiple oil guide ports 12 along the circumferential direction, and the multiple oil guide ports 12 are respectively aligned with the multiple inlet ends 411 of the radial oil inlet passages 41 of the two balancing plates 40.

[0052] This circumferential cross arrangement is intended to allow the cooling oil in the rotor shaft 10 to enter the axial oil passage 22 of the rotor core 20 in both directions, thereby realizing a two-way circulation of the cooling oil in the rotor core 20. This helps to enhance the flow efficiency and distribution uniformity of the cooling oil in the rotor core 20, maximize the cooling effect, and reduce the possibility of the cooling oil being retained in the rotor core 20, thereby helping to maintain the stable operation of the motor.

[0053] Taking this embodiment as an example, refer to Figure 2 As shown, the rotor assembly 100 includes ten cross-layout electrodes, which are divided into groups of five electrodes at intervals. Therefore, the flow direction of the cooling oil in the axial oil passages 22 of two adjacent groups of electrodes (i.e., two adjacent electrodes) presents an opposite trend, thus ensuring the bidirectional circulation of the cooling oil inside the rotor core 20, further enhancing the cooling effect.

[0054] In some embodiments, the radial oil inlet channel 41 can be set on the side where the balancing plate 40 abuts the rotor core 20, that is, the radial oil inlet channel 41 is grooved on the side of the balancing plate 40 close to the rotor core 20. The radial oil inlet channel 41 is actually a pipeline composed of iron sheets of the balancing plate 40 and the rotor core 20 for the circulation of cooling oil.

[0055] In some embodiments, Figure 4 As shown, the rotor core 20 may be provided with one or more other channels 24 in addition to the magnetic steel slots 21. These channels 24 may be channels used for cooling the original rotor core 20, or channels used for weight reduction. However, once the cooling oil enters these additional channels 24, the flow rate of the cooling oil entering the magnetic steel slots 21 will be reduced accordingly, which directly weakens the cooling effect on the magnetic steel 30. Therefore, measures must be taken to prevent the cooling oil from mistakenly entering any channel 24 other than the magnetic steel slots 21, so as to ensure the cooling efficiency of the cooling oil on the magnetic steel 30 in the magnetic steel slots 21.

[0056] like Figure 5 and Figure 6 As shown, a covering plate 23 is provided at each axial end of the rotor core 20 , and the covering plate 23 is used to cover at least one other oil channel except the magnetic steel slot 21 , to ensure that the cooling oil can accurately flow into the axial oil channel 22 of the magnetic steel slot 21 .

[0057] When the rotor core 20 is originally provided with channels 24 that are not the target cooling paths, the cover plate 23 can effectively block them to prevent the cooling oil from mistakenly entering these unnecessary channels. In this way, under the guidance of the radial oil inlet channel 41, the cooling oil can be concentrated through the outlet end 412 of the radial oil inlet channel 41 and accurately injected into the axial oil channel 22 inside the magnetic steel slot 21, thereby achieving direct cooling of the magnetic steel 30. The use of the cover plate 23 eliminates the need to re-produce the rotor core 20, greatly simplifies the structural modification process, and also significantly reduces the cost investment.

[0058] It should be noted that when no channel 24 of a non-target cooling path is preset on the rotor core 20, there is no need to add an additional cover plate 23 to avoid unnecessary redundancy. The material of the cover plate 23 should be consistent with the material of the rotor core 20, such as silicon steel sheet or nickel-iron alloy sheet, to ensure the coordination and uniformity of the material of the entire rotor assembly 100 and avoid unnecessary material consumption.

[0059] Based on the same inventive concept, the present disclosure provides a motor, including a rotor assembly 100 and a stator assembly. The stator assembly is sleeved on the outer wall of the rotor assembly 100, and the stator assembly is energized to generate a rotating magnetic field to drive the rotor assembly 100 to rotate. The specific manner of implementing the functions in the driving motor in the above embodiment has been described in detail in the embodiment of the rotor assembly 100, and will not be described in detail here.

[0060] In summary, by using expansion material to fix the magnet 30 and leaving an axial oil channel 22 in the magnet groove 21, the cooling oil can directly penetrate into the surface of the magnet 30, and the magnet 30 is efficiently and directly cooled. The smooth flow of cooling oil greatly improves the cooling speed of the magnet 30, helps to quickly dissipate the heat generated by the magnet 30 during operation, thereby significantly reducing the operating temperature of the magnet 30. Lower magnet 30 temperature means less energy loss, higher magnetic property retention and longer service life, which plays a key role in improving the performance of the overall drive motor.

[0061] It is to be understood that in the present disclosure, "plurality" refers to two or more than two, and other quantifiers are similar thereto. The singular forms "a", "an" and "the" are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0062] It should be further understood that the terms "radial", "axial", "inner", "outer", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present embodiment and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation.

[0063] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the utility model disclosed herein. This application is intended to cover any modification, use or adaptation of the present disclosure, which follows the general principles of the present disclosure and includes common knowledge or customary technical means in the art that are not disclosed in the present disclosure. The specification and examples are only considered to be exemplary, and the true scope and spirit of the present disclosure are indicated by the above-mentioned scope of rights.

[0064] It should be understood that the present disclosure is not limited to the precise structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the scope of the appended claims.

Claims

1. A rotor assembly (100), characterized in that: include: A rotor core (20), wherein the rotor core (20) is provided with a magnetic steel slot (21) extending axially therethrough; A magnetic steel (30), all sides of which are coated with expansion material, the magnetic steel (30) is embedded in the magnetic steel slot (21), the rotor core (20) is heated to expand the expansion material and to embed the magnetic steel (30) in the magnetic steel slot (21), After the expansion material expands, an oil gap is still left in the magnetic steel groove (21) to form an axial oil passage (22) for cooling oil to pass through and directly cool the magnetic steel (30).

2. The rotor assembly (100) according to claim 1, characterized in that: The rotor assembly (100) comprises two balancing plates (40) respectively arranged at two axial ends of the rotor core (20); the balancing plates (40) are provided with a plurality of radial oil inlet passages (41) arranged at intervals along the circumferential direction. The inlet end (411) of the radial oil inlet passage (41) is located on the radial inner end surface of the balance plate (40), and the outlet end (412) of the radial oil inlet passage (41) corresponds to the position of the axial oil passage (22) formed in the magnetic steel groove (21).

3. The rotor assembly (100) according to claim 2, characterized in that: In the circumferential direction, the radial oil inlet passages (41) of the two balancing plates (40) are staggered in the circumferential direction so that the cooling oil in the axial oil passages (22) in at least two adjacent magnetic steel grooves (21) flows in opposite directions.

4. The rotor assembly (100) according to claim 2, characterized in that: The outlet end (412) of the radial oil inlet passage (41) is provided with a plurality of branch oil passages (413), and the number and positions of the branch oil passages (413) correspond to the number and positions of the axial oil passages (22).

5. The rotor assembly (100) according to claim 2, characterized in that: The balancing plate (40) further comprises an oil outlet hole (42), wherein the oil outlet hole (42) axially penetrates the balancing plate (40) and corresponds to the axial oil passage (22) formed by the magnetic steel groove (21).

6. The rotor assembly (100) according to claim 2, characterized in that: The rotor assembly (100) further comprises a hollow rotor shaft (10), wherein the rotor core (20) and the balancing plate (40) of the rotor assembly (100) are both sleeved on the outer wall of the rotor shaft (10) in a torsion-resistant manner. The rotor shaft (10) is provided with an oil guide port (12) penetrating in the radial direction, and the oil guide port (12) is aligned with an inlet end (411) of the radial oil inlet passage (41) of the balance plate (40).

7. The rotor assembly (100) according to claim 2, characterized in that: The radial oil inlet passage (41) is located on a side of the balancing plate (40) that abuts against the rotor core (20).

8. The rotor assembly (100) according to claim 1, characterized in that The rotor core (20) further comprises one or more channels (24) in addition to the magnetic steel slots (21), and the rotor assembly (100) is provided with two covering plates (23), which are respectively arranged at two axial ends of the rotor core (20) and are used to cover the channels (24).

9. The rotor assembly (100) according to claim 1, characterized in that: The rotor core (20) is a lamination group formed by bonding multiple layers of metal laminations by an adhesive.

10. A driving motor, characterized in that: include: The rotor assembly (100) according to any one of claims 1 to 9; as well as A stator assembly is sleeved on the outer wall of the rotor assembly (100); when the stator assembly is energized, a rotating magnetic field is generated to drive the rotor assembly (100) to rotate.

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