Rotor assembly, motor and vehicle

Abstract

The utility model relates to a rotor assembly, a motor and a vehicle, the rotor assembly comprises a rotor disc, a soft magnetic composite element fixed on the rotor disc and a plurality of magnetic steels, and each magnetic steel is of an asymmetric structure relative to the radial direction of the rotor disc. According to the rotor assembly provided by the invention, the magnetic steel is designed to be asymmetrically arranged in the radial direction of the rotor disc, and compared with the magnetic steel which is symmetrically arranged, the torque ripple can be reduced, and the NVH performance of the motor can be improved. And a soft magnetic composite element is additionally arranged in the rotor disc, so that iron loss and eddy-current loss can be reduced.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of driving motor, and particularly relates to a rotor assembly, a motor and a vehicle. BACKGROUND

[0002] Axial flux motor, also known as disc motor, has obtained more and more attention in the motor industry due to its compact axial dimension, high electromechanical conversion efficiency, large power and torque density and other advantages. The rotor in the axial flux motor includes a plurality of magnetic steels, and the shape of the magnetic steels affects the magnetic field distribution and motor performance. In the related art, the axial flux motor adopts symmetrical magnetic steels, and the NVH performance and torque ripple performance thereof are poor. SUMMARY

[0003] In order to overcome the problems in the related art, the present disclosure provides a rotor assembly and a motor.

[0004] According to a first aspect of the embodiments of the present disclosure, a rotor assembly is provided, comprising a rotor disc, a soft magnetic composite element fixed to the rotor disc, and a plurality of magnetic steels, wherein each of the magnetic steels is a non-symmetrical structure with respect to the radial direction of the rotor disc.

[0005] Optionally, the magnetic steel has an inner arc, an outer arc, and a first bevel and a second bevel connecting two ends of the inner arc and the outer arc, and the outer end of the first bevel and / or the second bevel is inclined in the clockwise direction or in the counterclockwise direction relative to the inner end.

[0006] Optionally, the inner arc corresponds to a central angle of , and the outer arc corresponds to a central angle of , wherein is greater than , and the bevel angle β is staggered in the clockwise or counterclockwise direction.

[0007] Optionally, , wherein is the number of poles of the motor, is the pole arc coefficient of the magnetic steel.

[0008] Optionally, , wherein s is the number of slots of the stator core in the motor, and N is a positive rational number.

[0009] Optionally, the rotor disc comprises a back plate, and the soft magnetic composite elements are fixed to the back plate and are sequentially arranged in the circumferential direction.

[0010] Optionally, the rotor disc comprises a pressing plate mounted on the back plate, the pressing plate having a main body portion and a plurality of spokes arranged in a radial disc, the spokes having a first end connected with the main body portion and a second end opposite to the first end, wherein the second end of the spokes is inclined relative to the first end in a clockwise direction or in an anticlockwise direction.

[0011] Optionally, the rotor disc comprises a sheath sleeved on the outer periphery of the plurality of magnetic steels, the sheath being capable of closing the opening.

[0012] According to a second aspect of the embodiments of the present disclosure, a motor is provided, comprising the rotor assembly described above.

[0013] According to a third aspect of the embodiments of the present disclosure, a vehicle is provided, comprising the motor described above.

[0014] The technical solutions provided by the embodiments of the present disclosure can have the following beneficial effects: in the rotor assembly provided by the present disclosure, the magnetic steels are designed to be arranged asymmetrically with respect to the radial direction of the rotor disc, compared with the symmetrically arranged magnetic steels, the torque ripple can be reduced, and the NVH performance of the motor can be improved. Furthermore, the soft magnetic composite element is additionally arranged in the rotor disc, the iron loss and the eddy current loss can be reduced.

[0015] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0016] The accompanying drawings, which are incorporated into and form part of the specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0017] Figures 1 to 3 is a perspective view of a rotor assembly according to an exemplary embodiment.

[0018] Figures 4 to 6 is a structural schematic view of a back plate in a rotor assembly according to an exemplary embodiment.

[0019] Figures 7 to 9 is an assembly schematic view of a soft magnetic composite element in a rotor assembly according to an exemplary embodiment.

[0020] Figure 10 and Figure 11 is an assembly schematic view of a pressing plate in a rotor assembly according to an exemplary embodiment.

[0021] Figure 12 and Figure 13 is an assembly schematic view of a magnetic steel in a rotor assembly according to an exemplary embodiment.

[0022] Figures 14 to 16 This is a schematic diagram of the structure of a pressure plate in a rotor assembly from different perspectives, according to an exemplary embodiment.

[0023] Figure 17 This is a schematic diagram of the structure of a sheath in a rotor assembly according to an exemplary embodiment.

[0024] Figure 18 and Figure 19 This is a schematic diagram of the structure of a soft magnetic composite element in a rotor assembly according to an exemplary embodiment.

[0025] Figures 20 to 22 This is a schematic diagram of the structure of a magnet in a rotor assembly according to an exemplary embodiment.

[0026] Figure 23 This is a schematic diagram of the structure of an electric motor according to an exemplary embodiment.

[0027] Figure 24 This is an exploded view of an electric motor according to an exemplary embodiment.

[0028] Figure 25 This is an exploded view of the stator in an electric motor according to an exemplary embodiment.

[0029] Figure 26 This is a schematic diagram of the structure of a cooling circuit for an electric motor according to an exemplary embodiment.

[0030] Explanation of reference numerals in the attached figures

[0031] 1-Rotor disc; 11-Back plate; 110-Rib; 111-First platform; 112-Second platform; 1120-First fastening hole; 113-Third platform; 1130-Weight reduction hole; 1131-Mounting hole; 114-Overlapping edge; 12-Pressure plate; 120-Main body; 121-Spoke; 1200-Second fastening hole; 1210-Groove; 1211-First end; 1212-Second end; 10-Limiting space; 100-Opening; 13-Sheath; 14- Fastener; 2-Soft magnetic composite element; 21-Positioning groove; 3-Magnet; 31-Step section; 301-Inner arc; 302-Outer arc; 303-First inclined side; 304-Second inclined side; 4-Shell; 41-Shell body; 411-Liquid inlet; 412-Liquid outlet; 42-End cap; 5-Stator core; 500-Stator slot; 501-First chamber; 502-Second chamber; 51-Cover plate; 52-Inner ring fixing ring; 53-Fixing component; 6-Stator winding; 7-Shaft. Detailed Implementation

[0032] The exemplary embodiments will be described in detail herein with reference to the attached drawings. In the following description, the same numbers are used to denote the same 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 apparatuses and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0033] In the present disclosure, the orientation words such as "circumferential", "radial" generally refer to the rotation axis of the motor provided in the present disclosure, and "inner" and "outer" can refer to the inner and outer of the corresponding component profile or the inside and outside of the environment where it is located according to the specific context. In addition, in the following description, the same numbers in different drawings represent the same or similar elements, unless otherwise indicated. The terms "first", "second", and the like used in the present disclosure are used to distinguish one element from another element, and do not have sequential and important meanings.

[0034] In the axial flux motor, the shape of the magnetic steel affects the magnetic field distribution and the motor performance. In the related art, the axial flux motor adopts a symmetrical magnetic steel, which has poor NVH performance and torque ripple performance.

[0035] Based on this, according to a first aspect of the present disclosure, as shown in Figures 1 to 13 A rotor assembly is provided, which includes a rotor disc 1 and a soft magnetic composite element 2 and a plurality of magnetic steels 3 fixed on the rotor disc, wherein each magnetic steel 3 is a non-symmetrical structure with respect to the radial direction of the rotor disc. The "non-symmetrical structure" here is in relation to the symmetrical magnetic steel in the prior art, in which the end of the outer ring of the magnetic steel and the end of the inner ring of the magnetic steel are usually located in the same radial direction, and in the non-symmetrical magnetic steel, the outer ring of the magnetic steel and the inner ring of the magnetic steel are staggered by an angle of inclination in the circumferential direction, and the end of the outer ring of the magnetic steel and the end of the inner ring of the magnetic steel are not located in the same radial direction to form a non-symmetrical structure.

[0036] In the rotor assembly provided in the present disclosure, the magnetic steel 3 is designed as a non-symmetrical structure, and the outer ring of the magnetic steel and the inner ring of the magnetic steel are staggered by a certain angle in the circumferential direction, which can effectively reduce the cogging effect, thereby reducing the cogging torque and the motor torque ripple and improving the NVH performance of the motor. At the same time, the soft magnetic composite element 2 is additionally provided on the rotor disc, which can reduce the iron loss and eddy current loss.

[0037] As shown in Figure 20 and Figure 21As shown, the magnet 3 has an inner arc 301, an outer arc 302, and a first inclined side 303 and a second inclined side 304 connecting the two ends of the inner arc 301 and the outer arc 302. The outer ends of the first inclined side 303 and / or the second inclined side 304 are inclined clockwise or counterclockwise relative to the inner ends. In the embodiment shown in the figure, the outer end of the first inclined side 303 is inclined counterclockwise relative to the inner end, and the outer end of the second inclined side 304 is inclined counterclockwise relative to the inner end. Of course, this disclosure also includes embodiments where the outer end of the first inclined side 303 is inclined clockwise relative to the inner end, and the outer end of the second inclined side 304 is inclined clockwise relative to the inner end; it also includes embodiments where only the outer ends of the first inclined side 303 or only the second inclined side 304 are inclined clockwise relative to the inner end; and it also includes embodiments where only the outer ends of the first inclined side 303 or only the second inclined side 304 are inclined counterclockwise relative to the inner end. All of these can form an asymmetrical magnet and are all within the protection scope of this disclosure. In addition, several magnets 3 in this disclosure can adopt the same asymmetrical structure, which facilitates the processing and fixing of multiple magnets.

[0038] like Figure 22 As shown, the central angle corresponding to the inner arc 301 is The central angle corresponding to the outer arc 302 is ,in, Compared to The oblique polar angle β is offset along a clockwise or counterclockwise direction. In the embodiment shown in the figure, Compared to This disclosure also includes offsetting the oblique polar angle β in a counterclockwise direction. Compared to In embodiments where the slant angle β is offset clockwise, this disclosure also includes slant only on one side of the arc (left side in the figure), i.e. Greater than Furthermore, in embodiments with a slant angle greater than β, this disclosure also includes embodiments where the slant is only on one side of the arc (right side in the figure), i.e. Greater than Furthermore, embodiments with a slant angle β greater than β are also possible. The specific value of the slant angle β can be limited as needed, and this disclosure does not impose any limitations on it. The outer arc 302 of the magnet 3 is offset from the inner arc 301 in the circumferential direction by a slant angle β, which can increase the nonlinear element and effectively reduce the cogging effect (the cogging effect is a periodic torque with an angle, which will produce torque fluctuations and corresponding speed fluctuations).

[0039] In a preferred embodiment of this disclosure, ,in, This represents the number of poles of the motor. This represents the polar arc coefficient of the magnet. The central angle corresponding to the inner arc 301 is... The central angle corresponding to the outer arc Equal, can eliminate the tooth slot effect to the greatest extent. Here, the pole number of the motor, that is, the number of magnetic poles of the motor, the magnetic poles are N poles and S poles, one N pole and one S pole are generally referred to as a pair of magnetic poles, that is, the pole pair number is 1, so the pole pair number of the motor is 1, 2, 3, 4, and the pole number of the motor is 2, 4, 6, 8. The pole arc coefficient refers to the coefficient of the actual air gap magnetic field distribution under one pole pitch, which is determined by the distribution curve of the magnetic field, and thus it is determined by the shape of the excitation magnetic potential distribution curve, the uniformity of the air gap, and the saturation degree of the magnetic circuit. In the case of the existing pole arc coefficient, the pole arc coefficient refers to the ratio of the average value of the air gap magnetic induction intensity formed per pole to the maximum value.

[0040] In the present disclosure, Wherein s is the number of slots of the stator core in the motor, specifically referring to the number of stator slots 500 which will be introduced below, N is a positive rational number, N can be 0.5, 1, 2, 3, etc. In the preferred embodiment of the present disclosure, N = 1, the outer circular arc 302 is circumferentially offset from the inner circular arc 301 by an angle of one stator tooth (the included angle between the center lines of two adjacent stator slots 500), which correlates the skew pole angle of the magnetic steel with the angle of the stator tooth, effectively reducing the cogging effect.

[0041] Further, considering that the soft magnetic composite element 2 has excellent magnetic properties, low eddy current loss and high magnetic permeability, the rotor assembly provided by the present disclosure is additionally provided with a soft magnetic composite element 2. In the present disclosure, as shown in Figures 4 to 9 The rotor disc 1 includes a back plate 11, and the soft magnetic composite element 2 is fixed on the back plate 11. The soft magnetic composite element 2 can be a whole piece fixed directly on the back plate 11, or a plurality of soft magnetic composite elements 2 arranged in sequence in the circumferential direction. The plurality of soft magnetic composite elements 2 can be of the same structure or different structures, all of which belong to the protection scope of the present disclosure. Compared with the embodiment in which the entire back plate 11 is made of soft magnetic composite material, designing the soft magnetic composite element 2 as a plurality of elements can reduce the cost.

[0042] In order to stably fix the plurality of soft magnetic composite elements 2 on the back plate 11, the back plate 11 has a first platform 111 and a second platform 112 arranged protrudingly, the diameter of the first platform 111 is greater than that of the second platform 112, and the height of the second platform 112 is greater than that of the first platform 111. The soft magnetic composite element 2 is fixed on the first platform 111, and the plurality of soft magnetic composite elements 2 are arranged in sequence in the circumferential direction around the second platform 112. The top surface of the soft magnetic composite element 2 is flush with the surface of the second platform 112 to form the structure as shown in Figure 9 Here, the flush of the top surface of the soft magnetic composite element 2 with the surface of the second platform 112 can provide a stable plane for the fixation of the rear magnetic steel 3, facilitating the installation and fixation of the rear magnetic steel 3 in the later stage.

[0043] As shown in Figure 4, Figure 18 and Figure 19 As shown, the first platform 111 is provided with multiple circumferentially spaced protrusions 110, and the soft magnetic composite element 2 has a positioning groove 21 that cooperates with the protrusions 110 for positioning. Through the cooperation of the protrusions 110 and the positioning groove 21, multiple soft magnetic composite elements 2 can be pre-positioned to ensure the installation position of each soft magnetic composite element 2, and facilitate the subsequent fixing of the soft magnetic composite element 2 and the back plate 11 with glue.

[0044] In this embodiment, as Figure 18 and Figure 19 As shown, the soft magnetic composite element 2 can be a fan-shaped structure, with the positioning groove 21 extending radially and located in the middle of the fan-shaped structure. This ensures that the areas of the soft magnetic composite elements 2 on both sides of the rib 110 are not significantly different, facilitating the docking of the rib 110 and the positioning groove 21. In other embodiments, the soft magnetic composite element 2 can also be designed as a ring structure, with multiple soft magnetic composite elements 2 arranged radially from the inside out. The rib 110 can be arranged circumferentially, and the shape of the rib 110 matches the shape of the positioning groove 21. The cross-section of the rib 110 can be square, semi-circular, etc.

[0045] In this disclosure, the surfaces of the soft magnetic composite element 2 and the back plate 11 that are in contact with each other, and the two adjacent soft magnetic composite elements 2 are respectively bonded and fixed. Here, they can be bonded and fixed by adhesive or by double-sided tape, etc. This disclosure does not limit this.

[0046] Furthermore, to achieve the fixation of several magnets 3, in this disclosure, as... Figures 10 to 16 As shown, the rotor disk provided in this disclosure also includes a pressure plate 12. The pressure plate 12 is mounted on the back plate 11 for fixing a number of magnets 3. The pressure plate 12 has a main body 120 and multiple spokes 121 arranged in a radial pattern. The soft magnetic composite element 2 and two adjacent spokes 121 together form a limiting space 10 for accommodating the magnets 3. The outer ends of two adjacent spokes 121 form an opening 100. The magnets 3 can be inserted into the limiting space 10 through the opening 100. The magnets 3 can be stably limited between the two spokes 121. After the rotor is assembled, it has good stability, thereby ensuring the stability of the motor operation.

[0047] To accommodate asymmetric magnets 3, such as Figure 15 and Figure 16As shown, the spoke 121 has a first end 1211 connected with the main body 120 and a second end 1212 opposite to the first end 1211, wherein the second end 1212 of the spoke 121 is inclined relative to the first end 1211 in a clockwise direction or in an anticlockwise direction. In an exemplary embodiment of the present disclosure, a plurality of spokes 121 can be inclined in the same direction, and the angle of inclination can be the oblique pole angle β, so that the limiting space 10 between two adjacent spokes 121 can completely match the shape of the magnetic steel 3, thereby ensuring the fixing effect on the magnetic steel 3. In the embodiment of only one side inclination, part of the spokes 121 are arranged in the radial direction, and the second end 1212 of part of the spokes 121 is inclined relative to the first end 1211.

[0048] As shown in Figure 7 , the back plate 11 has a third platform 113 arranged protruding, the diameter of the third platform 113 is smaller than the diameter of the second platform 112, and the height of the third platform 113 is greater than the height of the second platform 112, as shown in Figure 11 and Figure 14 , a plurality of spokes 121 are arranged in the circumferential direction of the main body 120, the main body 120 is sleeved on the third platform 113 and is installed on the second platform 112 by the fastener 14, and the surface of the main body 120 is flush with the top surface of the third platform 113. The thickness of the pressing plate 12 can be designed according to the thickness of the magnetic steel 3, and after assembly is completed, the surface where the plurality of magnetic steels 3 are located is flush with the surface where the pressing plate 12 is located, thereby facilitating subsequent assembly of the entire rotor. As shown in Figure 14 , a plurality of fastening holes 1200 are arranged on the main body 120, the fastening holes 1200 can be stepped holes, and the fastener 14 will not protrude from the surface of the main body 120, thereby ensuring the flatness of the entire surface after assembly is completed. The back plate 11 is provided with a mounting hole 1131 through which the rotating shaft 7 passes, and the rotating shaft 7 and the mounting hole 1131 can be in spline fit to drive the rotor to rotate. The third platform 113 of the back plate 11 is further provided with a weight-reducing hole 1130, which can reduce the weight of the entire back plate 11 and meet the lightweight design principle.

[0049] As shown in Figure 14 and Figure 21 , the cross section of the spoke 121 can be a T-shaped structure, and the two sides of the magnetic steel 3 are respectively provided with a stepped portion 31, the stepped portion 31 is matched with the tooth groove 1210 on one side of the T-shaped structure, and the surface of the magnetic steel 3 is flush with the top surface of the pressing plate 12. Through the cooperation of the stepped portion 31 and the tooth groove 1210, the spoke 121 can realize axial limiting of the magnetic steel 3, which is more stable and reliable.

[0050] In the embodiment where the magnetic steel 3 is of an asymmetric structure, the shape of the limiting space 10 formed between two adjacent spokes 121 is adapted to the shape of the magnetic steel 3, and the angle of the two adjacent spokes 121 can be designed according to the first and second inclined edges 303 and 304 of the magnetic steel 3. The mounting position of the pressing plate 12 is configured to have one magnetic steel 3 straddle two soft magnetic composite elements 2, and in the axial direction, the magnetic steel 3 can also play a fixing role on the soft magnetic composite element 2.

[0051] As shown in Figure 5 and Figure 6 , the back plate 11 has a lap joint edge 114 at the outer edge of the first platform 111, as shown in Figure 17 , the rotor assembly further includes a sheath 13 sleeved on the outer periphery of the plurality of magnetic steels 3, and the axial width of the sheath 13 is equal to the axial width of the lap joint edge 114. After sleeving the sheath 13, the end face of the sheath 13 can be in contact with the lap joint edge 114, and the plurality of magnetic steels 3 can be wrapped by the sheath 13 to offset the centrifugal force during high-speed rotation.

[0052] The assembly process of the rotor provided by the present disclosure is as follows: as shown in Figures 7 to 9 , the positioning groove 21 of the soft magnetic composite element 2 is aligned with the rib 110 on the back plate 11, and the plurality of soft magnetic composite elements 2 are sequentially fixed on the first platform 111, and the two are pressed and fixed in the axial direction by using glue; as shown in Figure 10 and Figure 11 , the pressing plate 12 is fixed on the second platform 112 of the back plate 11 by the fastener 14, the limiting space 10 is formed between the main body part 120 of the pressing plate 12, the two spokes 121, and the soft magnetic composite elements 2, glue is applied on the surface where the magnetic steel 3 and the soft magnetic composite element 2 are in contact and the surface where the pressing plate 12 is in contact, the magnetic steel 3 is inserted from the opening 100 along the radial direction, the fixation of the magnetic steel 3 is completed through the mutual cooperation of the step part 31 and the tooth groove 1210, and the plurality of magnetic steels 3 are sequentially inserted into the corresponding limiting spaces 10; finally, the sheath 13 is sleeved and mounted on the outside of the magnetic steels 3, and the assembly process of the entire rotor is completed.

[0053] According to the second aspect of the present disclosure, an electric machine is provided, which can be an axial flux electric machine, as shown in Figures 22 to 25 , the electric machine includes a housing 4, a rotor provided in the housing 4, a stator core 5, a stator winding 6, and a rotating shaft 7, the two end faces of the stator core 5 are respectively provided with a stator slot 500, the stator winding 6 is provided in the stator slot 500, and the two ends of the stator core 5 are respectively provided with a rotor, which can be the rotor assembly introduced in the above embodiments. The electric machine has all the beneficial effects of the above-mentioned rotor assembly, and will not be described in detail here.

[0054] In the electric machine, as shown in Figure 24 and Figure 25As shown, the housing 4 includes a housing body 41 and end caps 42 located at both ends. The stator and rotor are both located in the enclosed space formed by the housing body 41 and the end caps 42. The stator includes a stator core 5, a stator winding 6, an inner ring fixing ring 52, a fixing member 53, and cover plates 51 located at both ends. The rotor assemblies described above are respectively provided on the cover plates 51 on both sides.

[0055] like Figure 26 As shown, stator slots 500 are provided on both end faces of the stator core 5, and the stator winding 6 is installed in the stator slots 500. Radially arranged slots are provided on the outer peripheral wall of the stator core 5. These slots serve as cooling channels, guiding the cooling medium from the outer ring to the inner ring of the stator core 5, thereby cooling the stator core 5 and improving the cooling effect. The slots also allow the fixing member 53 to pass through the stator core 5, fixing it in both directions and solving the problem of reverse movement. This also does not affect the installation of the stator winding 6, ensuring the slot fill factor of the stator winding 6.

[0056] In this embodiment, to stably fix the stator core 5 within the housing 4, an inner ring retaining ring 52 is fixedly installed inside the stator core 5. A fixing member 53 passes through a slot in the stator core 5, with one end fixed to the inner wall of the housing 4 and the other end fixed to the inner ring retaining ring 52. The inner ring retaining ring 52 can be fixed in the inner ring of the stator core 5 using an interference fit. The fixing member 53 can be a spoke that can pass through the slot, with its outer side fixed to the inner wall of the housing 4 by bolts and its inner side fixed to the inner ring retaining ring 52 by rivets. This allows for bidirectional overall fixation of the stator core 5, housing 4, and inner ring retaining ring 52 in the axial direction, improving the overall strength and stability of the stator structure and thus enhancing the reliability of the motor.

[0057] Furthermore, in this motor, to achieve cooling and temperature reduction of the stator core 5 and stator winding 6, such as... Figure 26As shown, the shell body 41 is provided with a liquid inlet 411 and a liquid outlet 412, the outer peripheral wall of the stator core 5 and the inner wall of the shell body 41 form a first chamber 501, the inner side of the inner peripheral wall of the stator core 5 forms a second chamber 502, and the stator core 5 has a radially arranged slot hole, wherein the liquid inlet 411 and the liquid outlet 412 are in communication with the first chamber 501, and the first chamber 501 and the second chamber 502 are in communication through the slot hole. In this way, the cooling liquid flowing in from the liquid inlet 411 enters the first chamber 501, and at this time the cooling liquid has a relatively low temperature, part of the cooling liquid in the first chamber 501 flows along the outer ring under the action of gravity, and is collected at the liquid outlet 412 and flows out, thereby cooling and lubricating the stator core 5 and the stator winding 6 of the outer ring; another part of the cooling liquid in the first chamber 501 flows into the second chamber 502 through the slot hole, cools the stator core 5 and the stator winding 6 on the inner side, and flows out from the lower slot hole to the first chamber 501, is gathered at the liquid outlet 412 and flows out, forming a complete cooling circuit, thereby improving the heat dissipation effect of the stator core 5 and the stator winding 6.

[0058] According to a third aspect of the present disclosure, a vehicle is provided, which comprises the electric machine as described above, and has all the beneficial effects of the electric machine as described above, which will not be repeated here.

[0059] In the above detailed description, reference is made to the accompanying drawings, which show by way of illustration specific aspects in which the disclosure can be practiced. In this regard, reference is made to the orientation of the figures as described, in which terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are used to indicate directions or positional relationships. Since the components of the described devices can be positioned in a number of different orientations, the directional terms can be used for illustrative purposes, but are not limiting. It will be understood that other aspects can be utilized and structural or logical changes can be made without departing from the concepts of the present disclosure. Therefore, the following detailed description is not to be taken in a limiting sense.

[0060] It should be understood that the features of the various aspects of the present disclosure described herein can be combined with each other, unless specifically noted otherwise. As used herein, the term "and / or" includes any one of the associated listed items, as well as any combination of any two or more of the associated listed items; similarly, "at least one of" includes any one of the associated listed items, as well as any combination of any two or more of the associated listed items.

[0061] It should be understood that, unless otherwise expressly specified and limited, the terms "joining," "attaching," "installing," "connecting," "linking," "fixing," etc., used in the embodiments of this disclosure should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms herein based on the specific circumstances.

[0062] Furthermore, the term "above" as used herein with respect to components, elements, or material layers formed or located "above" a surface may be used to indicate that the component, element, or material layer is "indirectly" positioned (e.g., placed, formed, deposited, etc.) on the surface such that one or more additional components, elements, or layers are arranged between the surface and the component, element, or material layer. However, the term "above" as used with respect to components, elements, or material layers formed or located "above" a surface may also optionally have a specific meaning: that the component, element, or material layer is "directly" positioned (e.g., placed, formed, deposited, etc.) on the surface, for example, in direct contact with the surface.

[0063] Although terms such as “first,” “second,” and “third” may be used herein to describe various components, parts, regions, layers, or sections, these components, parts, regions, layers, or sections are not limited to these terms. Rather, these terms are used only to distinguish one component, part, region, layer, or section from another. Therefore, without departing from the teachings of the examples described herein, the first component, part, region, layer, or section mentioned in the examples may also be referred to as the second component, part, region, layer, or section. Furthermore, the terms “first” and “second” are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as “first” or “second” may explicitly or implicitly include at least one of that feature. In the description herein, “a plurality” means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0064] It should be understood that spatial relative terms, such as “above,” “upper,” “below,” and “lower,” are used herein to describe the relationship between one element and another shown in the figures. In addition to the orientation depicted in the figures, these spatial relative terms are also intended to encompass different orientations of the device in use or operation. For example, if the device in the figures is flipped, an element described as “above” or “upper” relative to another element would be “below” or “lower” relative to that other element. Thus, depending on the spatial orientation of the device, the term “above” encompasses both above and below orientations. Devices may have other orientations (e.g., rotated 90 degrees or in other orientations), and the spatial relative terms used herein should be interpreted accordingly.

[0065] Furthermore, the term “exemplary” is used herein to mean serving as an example, instance, or illustration. Any aspect or design described herein as “exemplary” is not necessarily to be construed as advantageous compared to other aspects or designs. Rather, the use of the term “exemplary” is intended to present the concept in a concrete manner. As used herein, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or.” That is, unless otherwise specified or clear from the context, “X applies A or B” is intended to mean any of the natural inclusive arrangements. That is, “X applies A or B” satisfies any of the foregoing instances if X applies A; X applies B; or both X applies A and B. Additionally, unless otherwise specified or clear from the context to refer to the singular form, the articles “a” and “an” as used in this application and the appended claims are generally understood to mean “one or more.”

[0066] Similarly, although this disclosure has been shown and described with respect to one or more implementations, equivalent variations and modifications will occur to those skilled in the art upon reading and understanding this specification and the accompanying drawings. This disclosure includes all such modifications and variations and is limited only by the scope of the claims. In particular, with respect to the various functions performed by the components described above (e.g., elements, resources, etc.), unless otherwise indicated, the terminology used to describe such components is intended to correspond to any component (functionally equivalent) that performs the specific function of the described component, even if structurally not equivalent to the disclosed structure. Furthermore, although specific features of this disclosure may have been disclosed with respect to only one of several implementations, such features may be combined with one or more other features of other implementations, as may be desired and advantageous to any given or particular application. Moreover, with regard to the terms “comprising,” “owning,” “having,” “having,” or variations thereof as used in the detailed description or claims, such terms are intended to be inclusive in a manner similar to the term “including.”

[0067] Other embodiments of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the features disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the disclosure being indicated by the following claims.

[0068] It should be understood that the present disclosure is not limited to the precise structures herein described and illustrated in the drawings, and that various modifications and changes can be made without departing from its scope. The scope of the present disclosure is limited only by the claims that follow.

Claims

1. A rotor assembly characterized by, The rotor assembly comprises a rotor disc, a soft magnetic composite element fixed on the rotor disc, and a plurality of magnetic steels, wherein each of the magnetic steels is asymmetric in a radial direction of the rotor disc.

2. The rotor assembly of claim 1, wherein The magnetic steel has an inner arc, an outer arc, and a first slanting edge and a second slanting edge connecting two ends of the inner arc and the outer arc, and an outer end of the first slanting edge and / or the second slanting edge is inclined in a clockwise direction or in an anticlockwise direction relative to an inner end.

3. The rotor assembly of claim 2, wherein The central angle corresponding to the inner arc is The central angle corresponding to the outer arc is ,in, Compared to The oblique polar angle β is offset in a clockwise or counterclockwise direction.

4. The rotor assembly of claim 3, wherein wherein, is the number of poles of the motor, is the pole arc factor of the magnet.

5. The rotor assembly of claim 3, wherein where s is the number of slots in the stator core of the electric machine and N is a positive rational number.

6. The rotor assembly of any one of claims 1-5, wherein, The rotor disc comprises a back plate, and the soft magnetic composite element is fixed on the back plate and is a plurality of elements arranged in a circumferential direction.

7. The rotor assembly of claim 6, wherein The rotor disc comprises a pressing plate mounted on the back plate, and the pressing plate has a main body and a plurality of spokes arranged in a radial disc shape, the spokes have a first end connected with the main body and a second end opposite to the first end, and the second end of the spokes is inclined in a clockwise direction or in an anticlockwise direction relative to the first end.

8. The rotor assembly of claim 7, wherein The soft magnetic composite element and two adjacent spokes form a limiting space for accommodating the magnetic steel, and outer ends of the two adjacent spokes form an opening, the magnetic steel can be inserted into the limiting space from the opening, and the rotor disc comprises a sheath sleeved on outer peripheries of the plurality of magnetic steels, and the sheath can close the opening.

9. An electric machine characterized by The motor comprises the rotor assembly of any one of claims 1-8.

10. A vehicle characterized by comprising: The motor comprises the rotor assembly of claim 9.

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