Rotor assembly, motor and electric vehicle

Abstract

The present application provides a rotor assembly, a motor, and an electric vehicle. The rotor assembly includes a rotor punching, on which magnetic steel slots and air slots spaced apart from each other are provided; the air slots are provided in an area on the side of the magnetic steel slot away from the center of the rotor punching; in this area, n air slots are provided, n is an even number, and 4≤n≤8; all the air slots are symmetrically arranged with respect to the d-axis of the rotor punching in this area. The present application adds a specific number of air slots in an area on the side of the rotor punching where the magnetic steel slot is away from the center of the rotor punching, thereby increasing the q-axis inductance of the motor, improving the salient pole ratio, increasing the reluctance torque of the motor, effectively improving the power density of the motor, increasing the output torque of the motor, improving the output capacity of the motor, and improving the anti-demagnetization capability of the motor.

Description

Technical Field

[0001] The present application belongs to the technical field of electric vehicles, and specifically relates to a rotor assembly, a motor and an electric vehicle. Background Art

[0002] With increasing attention to environmental protection and efficient energy utilization, the "four modernizations" of the automotive industry have become a consensus, and the trend toward electrification is growing stronger. Drive motors, as key components for energy conversion in new energy vehicles, have a significant impact on these vehicles. Permanent magnet synchronous motors (PMSMs) are widely used in pure electric and hybrid new energy vehicles due to their high torque density, high efficiency, excellent stability, and high reliability.

[0003] With the sharp rise in rare earth raw material prices, rare earth motors are facing increasing cost pressure. The need to maximize torque at the lowest cost to meet vehicle performance and improve motor cost-effectiveness is paramount. Therefore, the development of relatively low-cost reluctance motors is crucial. However, the development of reluctance motors often suffers from issues such as low torque due to the rotor's magnetic steel material, topology, and motor type. Summary of the Invention

[0004] Therefore, the present application provides a rotor assembly, a motor and an electric vehicle, which can solve the problem of low motor efficiency caused by small torque in the prior art.

[0005] In order to solve the above problems, the present application provides a rotor assembly, comprising:

[0006] A rotor punching, wherein the rotor punching is provided with a magnetic steel slot and an air slot spaced apart from each other; the air slot is provided in an area on a side of the magnetic steel slot away from the center of the rotor punching;

[0007] In this region, there are n air slots, where n is an even number and 4≤n≤8; all the air slots are symmetrically arranged with respect to the axis d of the rotor punching in this region.

[0008] Optionally, all the air slots in the region are arranged to form a V-shaped structure, and the opening of the V-shaped structure faces the outer periphery of the rotor punching.

[0009] Optionally, n=6; the air slot includes a first air slot, a second air slot, a third air slot, a fourth air slot, a fifth air slot and a sixth air slot, the first air slot, the third air slot and the fifth air slot are located on one side of the d-axis, and the second air slot, the fourth air slot and the sixth air slot are located on the other side of the d-axis; the first air slot and the second air slot, the third air slot and the fourth air slot, and the fifth air slot and the sixth air slot are all symmetrically arranged with respect to the d-axis.

[0010] Optionally, the first air slot and the third air slot are arranged in a row, the second air slot and the fourth air slot are arranged in a row, and the two rows constitute the V-shaped structure; the fifth air slot and the sixth air slot are located in the slots of the V-shaped structure.

[0011] Optionally, the groove edge of the fifth air groove or the sixth air groove is formed by connecting the first straight side, the second straight side, the elliptical arc side and the third straight side in sequence, and the second straight side is closer to the d-axis relative to the third straight side; the major axes of the ellipses in which the two elliptical arc sides are located are cross-arranged to form a V-shape with the opening facing the outer periphery of the rotor punching.

[0012] Optionally, the groove edge of the first air groove or the second air groove is formed by connecting a first straight side, a second straight side, an elliptical arc side and a third straight side in sequence, and the second straight side is closer to the d-axis relative to the third straight side; the third air groove or the fourth air groove is set to be elliptical.

[0013] Optionally, the first straight edge and the third straight edge are connected by an arc transition.

[0014] Optionally, the major axis of the ellipse where the elliptical arc edge in the first air slot is located is on the same straight line as the major axis of the ellipse of the third air slot; the major axis of the ellipse where the elliptical arc edge in the second air slot is located is on the same straight line as the major axis of the ellipse of the fourth air slot.

[0015] Optionally, the shortest distance between the major axis endpoint of the ellipse where the elliptical arc edge in the first air slot is located and the major axis endpoint of the ellipse of the third air slot is set to mn, satisfying 0.5mm≤mn≤0.7mm.

[0016] Optionally, the connection point between the second straight side and the elliptical arc side, and the connection point between the third straight side and the elliptical arc side, are respectively the endpoints of the minor axes of the ellipse to which the elliptical arc side belongs.

[0017] Optionally, the major axis length of the ellipse where the elliptical arc edge is located in the first air slot or the second air slot is set to a1, and the minor axis length is set to b1, satisfying 8.5mm≤a1≤11mm, 2mm≤b1≤3mm; the major axis length of the ellipse of the third air slot or the fourth air slot is set to a2, and the minor axis length is set to b2, satisfying 10mm≤a2≤12.5mm, 2mm≤b2≤3mm; the major axis length of the ellipse where the elliptical arc edge is located in the fifth air slot or the sixth air slot is set to a3, and the minor axis length is set to b3, satisfying 8.5mm≤a3≤11mm, 2mm≤b3≤3mm.

[0018] Optionally, the angle between the major axis of the ellipse where the elliptical arc edge in the first air slot is located and the major axis of the ellipse where the elliptical arc edge in the second air slot is located is set to A1, the angle between the second straight edge in the first air slot and the second straight edge in the second air slot is set to A3, the angle between the third straight edge in the first air slot and the third straight edge in the second air slot is set to A4, and the angle between the major axis of the ellipse where the elliptical arc edge in the fifth air slot is located and the major axis of the ellipse where the elliptical arc edge in the sixth air slot is located is set to A2, satisfying 68°≤A1≤72°, 10°≤A1-A2≤12°, 105°≤A3≤110°, and 33°≤A4-A1≤36°.

[0019] Optionally, the magnetic steel slot includes a first magnetic steel slot, a second magnetic steel slot, a third magnetic steel slot, a fourth magnetic steel slot and a fifth magnetic steel slot, the first magnetic steel slot and the third magnetic steel slot are located on one side of the d-axis, and the second magnetic steel slot and the fourth magnetic steel slot are located on the other side of the d-axis; the first magnetic steel slot and the second magnetic steel slot, the third magnetic steel slot and the fourth magnetic steel slot are symmetrically arranged with respect to the d-axis, and are inclined relative to the d-axis; the fifth magnetic steel slot is symmetrically arranged with respect to the d-axis, and forms a U-shape with the third magnetic steel slot and the fourth magnetic steel slot; the first magnetic steel slot and the second magnetic steel slot form a V-shape, and are arranged in the U-shaped slot.

[0020] Optionally, when there are six air slots, the major axis of the ellipse where the elliptical arc edge in the first air slot is located, and the major axis of the ellipse of the third air slot are located on the same straight line, and the straight line is set parallel to the side of the first magnetic steel slot.

[0021] Optionally, the minimum distance between the straight line and the side of the first magnetic steel slot is set to h, satisfying 4.8mm≤h≤6mm.

[0022] Optionally, the first side edge of the first magnetic steel slot close to the outer periphery of the rotor punching is connected to the adjacent second side edge away from the d-axis by an arc transition; the first intersection of the first side extension line and the second side extension line, and the second intersection of the first straight side extension line and the third straight side extension line in the first air slot, the angle formed by the first intersection and the second intersection and the line connecting the center of the rotor punching is set to A5; the third intersection of the first straight side extension line and the third straight side extension line in the fifth air slot, the angle formed by the second intersection and the third intersection and the line connecting the center of the rotor punching is set to A6; satisfying 8.5°≤A5≤10.5°, 5°≤A6≤6°.

[0023] According to another aspect of the present application, a motor is provided, comprising the rotor assembly as described above.

[0024] According to yet another aspect of the present application, an electric vehicle is provided, comprising the rotor assembly or the motor as described above.

[0025] Optionally, the electric vehicle has a load capacity of 3-4.5 tons, the stator outer diameter of the motor is 230 mm, the peak power is 70 kW-80 kW, the peak torque is 270 N·m-300 N·m, and the peak speed is 9000 rpm-12000 rpm.

[0026] A rotor assembly provided in the present application includes: a rotor punching, on which magnetic steel slots and air slots spaced apart from each other are provided; the air slots are provided in an area on a side of the magnetic steel slot away from the center of the rotor punching; in this area, there are n air slots, where n is an even number and 4≤n≤8; all the air slots are symmetrically arranged with respect to the d-axis of the rotor punching in this area.

[0027] The present application adds a specific number of air slots on the side area of ​​the rotor punching magnetic steel slot away from the center of the rotor punching circle, thereby increasing the q-axis inductance of the motor, improving the salient pole ratio, increasing the motor reluctance torque, effectively improving the power density of the motor, increasing the motor output torque, improving the output capacity of the motor, and improving the motor's anti-demagnetization ability. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A schematic diagram of a partial structure of a rotor assembly according to an embodiment of the present application;

[0029] Figure 2 A schematic diagram of a partial structure of a rotor assembly according to an embodiment of the present application;

[0030] Figure 3 This is a partial enlarged view of the air slot portion of the rotor assembly according to an embodiment of the present application;

[0031] Figure 4 A partial enlarged view of the air slot portion of the rotor assembly according to an embodiment of the present application;

[0032] Figure 5 A partial enlarged view of the air slot portion of the rotor assembly according to an embodiment of the present application;

[0033] Figure 6 This is a schematic structural diagram of the magnetic steel slot portion of the rotor assembly according to an embodiment of the present application;

[0034] Figure 7 This is an overall layout diagram of the rotor assembly according to an embodiment of the present application;

[0035] Figure 8 This is a demagnetization simulation effect diagram of the motor according to an embodiment of the present application;

[0036] Figure 9This is a comparison diagram of the torque ripple between the motor according to the embodiment of the present application and a traditional motor.

[0037] The reference numerals indicate:

[0038] 1. Rotor lamination; 2. Air slot; 3. Magnetic steel slot; 4. Magnetic steel; O. Center of rotor lamination; I. d-axis; 21. First air slot; 22. Second air slot; 23. Third air slot; 24. Fourth air slot; 25. Fifth air slot; 26. Sixth air slot; 31. First magnetic steel slot; 32. Second magnetic steel slot; 33. Third magnetic steel slot; 34. Fourth magnetic steel slot; 35. Fifth magnetic steel slot; 41. First magnetic steel; 42. Second magnetic steel; 43. Third magnetic steel; 44. Fourth magnetic steel; 45. Fifth magnetic steel; 211. First straight edge of first air slot; 212. Second straight edge of first air slot; 213. Third straight edge of first air slot; 2 14. Elliptical arc edge; 221. First straight side of the second air slot; 222. Second straight side of the second air slot; 223. Third straight side of the second air slot; 224. Elliptical arc edge; 231. Ellipse; 241. Ellipse; 251. First straight side of the fifth air slot; 252. Second straight side of the fifth air slot; 253. Third straight side of the fifth air slot; 254. Elliptical arc edge; 311. First side of the first magnetic steel slot; 312. Second side of the first magnetic steel slot; 313. Third side of the first magnetic steel slot; E1. The ellipse where the elliptical arc edge of the first air slot is located; E2. The ellipse where the elliptical arc of the third air slot is located; E3. The ellipse where the elliptical arc edge of the fifth air slot is located. DETAILED DESCRIPTION

[0039] To make the purpose, technical solutions, and advantages of this application more clear, the technical solutions of this application will be clearly and completely described below in conjunction with the specific embodiments of this application and the corresponding drawings. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0040] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in a sequence other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0041] See also Figures 1 to 9 As shown, according to an embodiment of the present application, a rotor assembly includes:

[0042] A rotor punching 1, wherein the rotor punching 1 is provided with a magnetic steel slot 3 and an air slot 2 spaced apart from each other; the air slot 2 is provided in an area on a side of the magnetic steel slot 3 away from the center O of the rotor punching 1;

[0043] In this region, n air slots 2 are provided, where n is an even number and 4≤n≤8; all the air slots 2 are symmetrically arranged with respect to the rotor punching d axis I in this region.

[0044] The present application adds a specific number of air slots 2 in the area on the side of the rotor punching magnetic steel slot 3 away from the center O of the rotor punching circle, thereby increasing the q-axis inductance of the motor, improving the salient pole ratio, increasing the motor reluctance torque, effectively improving the power density of the motor, increasing the motor output torque, improving the output capacity of the motor, and improving the motor's anti-demagnetization ability.

[0045] The following is a detailed description of a rotor with a UV-type magnetic steel slot structure. However, for other reluctance motor rotor structures, such as those with different numbers and layouts of magnetic steel slots, if there is sufficient space on the peripheral magnetic poles of the magnetic steel slots, the air slot structure can also be used for optimization.

[0046] like Figure 1 FIG. 1 is a schematic diagram of the structure of one-sixth of the rotor punching 1 of the present application. The rotor punching 1 has an air slot 2, a magnetic steel slot 3, and a magnetic steel 4. The magnetic steel 4 is inserted into the magnetic steel slot 3.

[0047] The air slots 2 include a first air slot 21, a second air slot 22, a third air slot 23, a fourth air slot 24, a fifth air slot 25, and a sixth air slot 26. The first air slot 21 and the second air slot 22 are symmetrical about the d-axis I; the third air slot 23 and the fourth air slot 24 are symmetrical about the d-axis I; and the fifth air slot 25 and the sixth air slot 26 are symmetrical about the d-axis I of the rotor lamination 1. The first air slot 21 and the second air slot are located at the rear ends of the third air slot 23 and the fourth air slot 23, respectively, near the outer edge of the rotor. The first air slot 21, the second air slot 22, the third air slot 23, and the fourth air slot 24 form a "V" shape, with their openings facing the outer edge of the rotor; the fifth air slot 25 and the sixth air slot 26 form a small "V" shape, with their openings facing the outer edge of the rotor.

[0048] The magnetic steel slot 3 includes a first magnetic steel slot 31, a second magnetic steel slot 32, a third magnetic steel slot 33, a fourth magnetic steel slot 34, and a fifth magnetic steel slot 35. The first magnetic steel slot 31 is symmetrical with the second magnetic steel slot 32 about the d-axis I; the third magnetic steel slot 33 is symmetrical with the fourth magnetic steel slot 34 about the d-axis I; and the fifth magnetic steel slot 35 is located between the third magnetic steel slot 33 and the fourth magnetic steel slot 34, which are close to the center of the rotor. The first magnetic steel slot 31 and the second magnetic steel slot 32 form a "V" shape, with the opening facing the outer edge of the rotor; the third magnetic steel slot 33, the fourth magnetic steel slot 34, and the fifth magnetic steel slot 35 form a "U" shape, with the opening facing the outer edge of the rotor. Combined with the air slot, the entire rotor topology presents a "UVVV" shape.

[0049] The magnetic steel 4 includes a first magnetic steel 41 , a second magnetic steel 42 , a third magnetic steel 43 , a fourth magnetic steel 44 , and a fifth magnetic steel, which are respectively installed in corresponding magnetic steel slots 3 .

[0050] The present application provides several air slots between the first magnetic steel slot 31 and the second magnetic steel slot 32 on the rotor punching 1. The first air slot 21, the second air slot 22, the third air slot 23, and the fourth air slot 24 form a "V" shape, with their openings facing the outer edge of the rotor. The fifth air slot 25 and the sixth air slot 26 form a small "V" shape, which functions to form a magnetic circuit between the first magnetic steel slot 31, the second magnetic steel slot 32 and the first air slot 21, the second air slot 22, the third air slot 23, and the fourth air slot 24. Similarly, another magnetic circuit is formed between the first air slot 21, the second air slot 22, the third air slot 23, and the fourth air slot 24 and the fifth air slot 25, and the sixth air slot 26. The overall arrangement of the air slots is designed to match the distribution of the first magnetic steel slot 31 and the second magnetic steel slot 32.

[0051] The air slots provided in this application can improve the q-axis inductance of the motor and the salient pole ratio relative to the solution without air slots, thereby increasing the motor's magnetic resistance torque and improving the output torque. The output torque of the motor is composed of permanent magnet torque and magnetic resistance torque.

[0052] In addition, regarding the number of air slots, on the one hand, space issues need to be considered, and on the other hand, mechanical strength and production process issues need to be considered. The air slots close to the outer periphery of the rotor are set as four air slots (two on one side) in consideration of mechanical strength issues. If two more slender air slots are set (one on one side), the mechanical strength of the magnetic isolation bridge between the air slots and the outer edge of the rotor will be poor; if the outer layer is set with more air slots (3 or more on one side), it may increase the difficulty of the process, or increase the leakage magnetic flux (between the air slots). In addition, regarding the number of air slot layers, this proposal sets two layers (large V, small V). Setting one layer is not as effective as two layers in increasing the q-axis inductance. Three layers or more may cause the magnetic circuit to be too narrow and the magnetic density to be too high due to space issues, affecting the output torque. Therefore, this application sets the air slots to be distributed in two layers, and sets two air slots on one side of the outer layer. This solution has better beneficial effects.

[0053] The first air slot 21 is formed by a first straight side 211, a second straight side 212, a third straight side 213, and an elliptical arc side 214. The end of the first straight side 211 away from the d-axis I is connected to the third straight side 213 by an arc transition, and the end close to the d-axis I is connected to the second straight side 212. The elliptical arc 214 connects the second straight side 212 and the third straight side 213.

[0054] The second air slot 22 is composed of a second air slot first straight side 221 , a second air slot second straight side 222 , a second air slot third straight side 223 and an elliptical arc 224 . The second air slot 22 is symmetrical to the first air slot 21 about the d-axis I.

[0055] The third air slot 23 is elliptical 231 , and the fourth air slot 24 is elliptical 241 .

[0056] The fifth air slot 25 is composed of a first straight side 251, a second straight side 252, a third straight side 253, and an elliptical arc side 254. The end of the first straight side 251 away from the d-axis I is connected to the third straight side 253 of the fifth air slot by an arc transition, and the end close to the d-axis I is connected to the second straight side 252 of the fifth air slot. The elliptical arc 254 connects the second straight side 252 of the fifth air slot and the third straight side 253 of the first air slot.

[0057] The sixth air groove 26 and the fifth air groove 25 are symmetrical about the d-axis I.

[0058] The air slots are primarily shaped using ellipses, elliptical arcs, and straight edges. Using other shapes (such as rectangles) may also yield similar beneficial effects on output torque. However, compared to other shapes, elliptical arcs can avoid stress concentration in the rotor's mechanical strength, increasing its reliability and safety. Furthermore, compared to other shapes, elliptical arcs can prevent localized high magnetic flux density on the rotor laminations, which can affect output torque.

[0059] The air slots can increase the q-axis inductance of the motor, improve the salient pole ratio, increase the motor reluctance torque, effectively improve the power density of the motor, increase the motor output torque, and improve the output capacity of the motor. In addition, the air slots can prevent the demagnetization of the magnetic steel and improve the anti-demagnetization ability of the motor. Figure 8 As shown, the demagnetization current is 1.9 times the peak current (a 3% drop in flux linkage is considered demagnetization). The elliptical arc in the air slot can avoid stress concentration, improve the mechanical strength of the rotor, and ensure the reliability of the motor.

[0060] The ellipse on which the elliptical arc edge 214 of the first air groove is located is E1, and the midpoint of the ellipse E1 is Q1. Q1, the endpoint of the second straight side 212 of the first air groove close to the midpoint, and the endpoint of the third straight side 213 of the first air groove close to the midpoint are collinear, and Q1 is the midpoint of the above two endpoints; the major axis of the ellipse E1 is a1, and the minor axis is b1. The value range of a1 is 8.5-11mm, preferably a1=10mm; the value range of b1 is 2-3mm, preferably b1=2.5mm.

[0061] The ellipse where the ellipse 231 of the third air groove is located is E2, the midpoint of the ellipse E2 is Q2, the major axis of the ellipse E2 is a2, and the minor axis is b2; the value range of a2 and b2 is a2=10-12.5mm, b2=2-3mm, preferably a2=11.8mm, b2=2.5mm.

[0062] The ellipse where the elliptical arc edge 254 of the fifth air groove 25 is located is E3, and the midpoint of the ellipse E3 is Q3. Q3 and the endpoint of the second straight side 252 of the fifth air groove close to the midpoint and the endpoint of the third straight side 253 of the fifth air groove close to the midpoint are collinear, and Q3 is the midpoint of the above two endpoints; the major axis of the ellipse E3 is a3, and the minor axis is b3. The value range of a3 is 8.5-11mm, preferably a3=10mm; the value range of b3 is 2-3mm, preferably b3=2.5mm.

[0063] The mating edge of the first magnetic steel slot 31 and the first magnetic steel 41 close to the d-axis I is the first magnetic steel slot first edge 311 .

[0064] The major axis a1 of ellipse E1 and the major axis a2 of ellipse E2 are collinear and parallel to the first side 311 of the first magnetic steel slot. The distance h between the line containing the major axis a1 of ellipse E1 and the major axis a2 of ellipse E2 and the first side 311 of the first magnetic steel slot is 4.8-6 mm, preferably 5.25. The end of the major axis a1 of ellipse E1 closest to the center is point M, and the end of the major axis a2 of ellipse E2 closest to the outer edge of the rotor is point N. The distance between them, M and N, is 0.5-0.7 mm, preferably 0.6 mm.

[0065] The midpoint positions of the above-mentioned ellipses E1, E2, and E3, the values ​​of the major and minor axes, the value of h, and the distance between MN can increase the q-axis inductance of the motor, improve the salient pole ratio, increase the motor reluctance torque, effectively improve the power density of the motor, reduce leakage flux, and improve the output capacity of the motor.

[0066] The angle between the straight line where the elliptical arc edge on the first air slot 21 and the second air slot 2 and the major axis of the ellipse is located is A1, and the angle between the straight line where the elliptical arc edge on the fifth air slot 25 and the sixth air slot 26 and the major axis of the ellipse is A2. A1 and A2 have a constraint relationship: A1 = 68°-72°, A1-A2 = 10°-12°, preferably A1 = 69.6°, and A1-A2 = 11.3°. The angle between the second straight edge 212 of the first air slot and the second straight edge 222 of the second air slot is A3, and the angle between the third straight edge 213 of the first air slot and the third straight edge 223 of the second air slot is A4. The value range of A3 is: 105°-110°, preferably A3 = 107.65°. A4 has a constraint relationship: A4-A1 = 33°-36°, preferably A4-A1 = 34.1°

[0067] The second side 312 of the first magnetic steel slot forms a magnetic isolation bridge with the outer periphery of the rotor. The second side 312 of the first magnetic steel slot connects to the third side 313 of the first magnetic steel slot via a circular arc transition at the end away from the d-axis I. The intersection of the extended lines of the second side 312 and the third side 313 of the first magnetic steel slot, and the intersection of the extended lines of the first side 211 and the third side 213 of the first air slot, are all connected with the center point O of the rotor punching. The angle between these two connecting lines is A5. The angle between the extended lines of the first straight side 211 and the third straight side 213 of the first air slot, and the extended lines of the first straight side 251 and the third straight side of the fifth air slot, through the rotor center point O, is A6. A5 = 8.5°-10.5°, preferably 9.5°; A6 = 5°-6°, preferably 5.66°.

[0068] The above constraint relationship can increase the q-axis inductance, improve the reluctance torque, effectively reduce the torque pulsation, and improve the motor efficiency. As shown in Figure 9, this solution is a comparison of the optimal solution of this application with the traditional solution. The left side is the output torque of this application (output torque 282.74N·m, torque pulsation 5.29%), and the right side is the output torque of the traditional solution (no air slot or the air slot is not within the constraint range) (output torque 273.95N·m, torque pulsation 12.14%), which can obviously improve the output torque and reduce the torque pulsation by 6.8%. For the non-optimal values ​​of each structure in this application, there are technical effects similar to the optimal values.

[0069] When the above-mentioned rotor assembly is used in the motor of a 3-4.5t logistics vehicle, the motor stator outer diameter is 230mm, the peak power is 70kW-80kW, the peak torque is 270N·m-300N·m, and the peak speed is 9000rpm-12000rpm.

[0070] It is easy for those skilled in the art to understand that the above embodiments can be freely combined and superimposed without conflict.

[0071] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application. The above description is merely a preferred embodiment of the present application. It should be noted that those skilled in the art can make various improvements and variations without departing from the technical principles of the present application, and such improvements and variations shall also be considered within the scope of protection of the present application.

Claims

1. A rotor assembly, characterized in that: include: A rotor punching (1), wherein the rotor punching (1) is provided with a magnetic steel slot (3) and an air slot (2) spaced apart from each other; the air slot (2) is provided in an area on a side of the magnetic steel slot (3) away from the center of the rotor punching (1); In this region, the air slots (2) are provided with n numbers, n is an even number, and 4≤n≤8; all the air slots (2) are symmetrically arranged with respect to the d-axis (I) of the rotor punching (1) in this region; The air slot (2) comprises a first air slot (21), a second air slot (22), a third air slot (23), a fourth air slot (24), a fifth air slot (25) and a sixth air slot (26); the first air slot (21), the third air slot (23) and the fifth air slot (25) are located on one side of the d-axis (I), and the second air slot (22), the fourth air slot (24) and the sixth air slot (26) are located on the other side of the d-axis (I); the first air slot (21) and the second air slot (22), the third air slot (23) and the fourth air slot (24), the fifth air slot (25) and the sixth air slot (26) are all symmetrically arranged with respect to the d-axis (I); The first air groove (21) and the third air groove (23) are arranged in a row, and the second air groove (22) and the fourth air groove (24) are arranged in a row, and the two rows form a V-shaped structure; the fifth air groove (25) and the sixth air groove (26) are located in the grooves of the V-shaped structure; The groove edges of the fifth air groove (25) and the sixth air groove (26) are formed by sequentially connecting a first straight side, a second straight side, an elliptical arc side, and a third straight side, and the second straight side is closer to the d-axis (I) relative to the third straight side; the major axes of the ellipses where the two elliptical arc sides are located are arranged crosswise, forming a V-shape with an opening facing the outer periphery of the rotor punching (1).

2. The rotor assembly according to claim 1, wherein: The groove edges of the first air groove (21) and the second air groove (22) are formed by sequentially connecting a first straight side, a second straight side, an elliptical arc side, and a third straight side, and the second straight side is closer to the d-axis (I) relative to the third straight side; the third air groove (23) or the fourth air groove (24) is set to be elliptical.

3. The rotor assembly according to claim 2, wherein: The first straight side and the third straight side of the first air groove (21) are connected by a circular arc transition; the first straight side and the third straight side of the second air groove (22) are connected by a circular arc transition.

4. The rotor assembly according to claim 2, wherein: The major axis of the ellipse where the elliptical arc edge (214) in the first air slot (21) is located is located on the same straight line as the major axis of the ellipse (231) of the third air slot (23); the major axis of the ellipse where the elliptical arc edge (224) in the second air slot (22) is located is located on the same straight line as the major axis of the ellipse (241) of the fourth air slot (24).

5. The rotor assembly according to claim 4, wherein: The shortest distance between the major axis endpoint of the ellipse where the elliptical arc edge (214) in the first air slot (21) is located and the major axis endpoint of the ellipse (231) of the third air slot (23) is set to MN, satisfying 0.5mm≤MN≤0.7mm.

6. The rotor assembly according to claim 2, wherein: The connection point between the second straight side of the first air slot (21) and the elliptical arc side, and the connection point between the third straight side of the first air slot (21) and the elliptical arc side, are respectively the minor axis endpoints of the ellipse where the elliptical arc side of the first air slot (21) is located; the connection point between the second straight side of the second air slot (22) and the elliptical arc side, and the connection point between the third straight side of the second air slot (22) and the elliptical arc side, are respectively the minor axis endpoints of the ellipse where the elliptical arc side of the second air slot (22) is located; The connection point between the second straight side of the fifth air slot (25) and the elliptical arc side, and the connection point between the third straight side of the fifth air slot (25) and the elliptical arc side, are respectively the minor axis endpoints of the ellipse where the elliptical arc side of the fifth air slot (25) is located; the connection point between the second straight side of the sixth air slot (26) and the elliptical arc side, and the connection point between the third straight side of the sixth air slot (26) and the elliptical arc side, are respectively the minor axis endpoints of the ellipse where the elliptical arc side of the sixth air slot (26) is located.

7. The rotor assembly according to claim 6, wherein: The major axis length of the ellipse where the elliptical arc edge is located in the first air slot (21) and the second air slot (22) is set to a1, and the minor axis length is set to b1, satisfying 8.5mm≤a1≤11mm, 2mm≤b1≤3mm; the major axis length of the ellipse where the elliptical arc edge is located in the third air slot (23) and the fourth air slot (24) is set to a2, and the minor axis length is set to b2, satisfying 10mm≤a2≤12.5mm, 2mm≤b2≤3mm; the major axis length of the ellipse where the elliptical arc edge is located in the fifth air slot (25) or the sixth air slot (26) is set to a3, and the minor axis length is set to b3, satisfying 8.5mm≤a3≤11mm, 2mm≤b3≤3mm.

8. The rotor assembly according to claim 7, wherein: The angle between the major axis of the ellipse where the elliptical arc side in the first air slot (21) is located and the major axis of the ellipse where the elliptical arc side in the second air slot (22) is located is set to A1, the angle between the second straight side in the first air slot (21) and the second straight side in the second air slot (22) is set to A3, the angle between the third straight side in the first air slot (21) and the third straight side in the second air slot (22) is set to A4, and the angle between the major axis of the ellipse where the elliptical arc side in the fifth air slot (25) is located and the major axis of the ellipse where the elliptical arc side in the sixth air slot (26) is located is set to A2, satisfying 68°≤A1≤72°, 10°≤A1-A2≤12°, 105°≤A3≤110°, and 33°≤A4-A1≤36°.

9. The rotor assembly according to any one of claims 1 to 4, characterized in that: The magnetic steel slot (3) comprises a first magnetic steel slot (31), a second magnetic steel slot (32), a third magnetic steel slot (33), a fourth magnetic steel slot (34) and a fifth magnetic steel slot (35), wherein the first magnetic steel slot (31) and the third magnetic steel slot (33) are located on one side of the d-axis (I), and the second magnetic steel slot (32) and the fourth magnetic steel slot (34) are located on the other side of the d-axis (I); the first magnetic steel slot (31) and the second magnetic steel slot (32), the third magnetic steel slot (33) and the fourth magnetic steel slot (34) are all symmetrically arranged with respect to the d-axis (I), and are all inclined relative to the d-axis (I); the fifth magnetic steel slot (35) is symmetrically arranged with respect to the d-axis (I), and forms a U-shape with the third magnetic steel slot (33) and the fourth magnetic steel slot (34); the first magnetic steel slot (31) and the second magnetic steel slot (32) form a V-shape and are arranged in the U-shaped slot.

10. The rotor assembly according to claim 9, wherein: The major axis of the ellipse where the elliptical arc edge in the first air slot (21) is located and the major axis of the ellipse of the third air slot (23) are located on the same straight line, and the straight line is arranged parallel to the side of the first magnetic steel slot (31).

11. The rotor assembly according to claim 10, wherein: The minimum distance between the straight line and the side of the first magnetic steel slot (31) is set to h, which satisfies 4.8mm≤h≤6mm.

12. The rotor assembly according to claim 10, wherein: The first side edge of the first magnetic steel slot (31) close to the outer periphery of the rotor punching (1) is connected to the second side edge adjacent to and away from the d-axis (I) by an arc transition; the first intersection of the first side extension line and the second side extension line, and the second intersection of the first straight side extension line and the third straight side extension line in the first air slot (21), the angle formed by the first intersection and the second intersection and the line connecting the center of the rotor punching (1) is set to A5; the third intersection of the first straight side extension line and the third straight side extension line in the fifth air slot (25), the angle formed by the second intersection and the third intersection and the line connecting the center of the rotor punching (1) is set to A6; satisfying 8.5°≤A5≤10.5°, 5°≤A6≤6°.

13. A motor, characterized in that: The invention comprises a rotor assembly according to any one of claims 1 to 12.

14. An electric vehicle, characterized in that: The invention comprises a rotor assembly according to any one of claims 1 to 12 or a motor according to claim 13.

15. The electric vehicle according to claim 14, characterized in that: The electric vehicle has a load capacity of 3-4.5 tons, a stator outer diameter of the motor of 230 mm, a peak power of 70 kW-80 kW, a peak torque of 270 N·m-300 N·m, and a peak speed of 9000 rpm-12000 rpm.

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