Motor rotor and permanent magnet motor

Abstract

The invention provides a motor rotor and a permanent magnet motor. The motor rotor comprises a rotor iron core, a plurality of permanent magnet grooves are formed in the rotor iron core, permanent magnets are arranged in the permanent magnet grooves, under one pole, the permanent magnets comprise the first permanent magnet, the second permanent magnet, the third permanent magnet and the fourth permanent magnet, the first permanent magnet and the third permanent magnet are located on the first side of a d-axis, and the fourth permanent magnet is located on the second side of the d-axis. The second permanent magnet and the fourth permanent magnet are located on the second side of the d-axis, the third permanent magnet is located on the side, close to the d-axis, of the first permanent magnet, the fourth permanent magnet is located on the side, close to the d-axis, of the second permanent magnet, and the magnetic induction coercive force of the first permanent magnet is smaller than that of the third permanent magnet. The magnetic induction coercive force of the second permanent magnet is smaller than that of the fourth permanent magnet, the length of the first permanent magnet is larger than that of the third permanent magnet, and the length of the second permanent magnet is larger than that of the fourth permanent magnet. According to the motor rotor, the demagnetization resistance of the permanent magnet motor can be improved, and the performance of the motor is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and in particular to a motor rotor and a permanent magnet motor. Background Art

[0002] A permanent magnet motor is an electric motor that uses permanent magnets as magnetic poles in its rotor or stator. It usually has high efficiency, high power density and good dynamic response characteristics. The selection and configuration of permanent magnets are crucial to the performance of the motor. Common permanent magnet materials include neodymium iron boron, samarium cobalt and ferrite, among which neodymium iron boron is the first choice for high power density permanent magnet motors due to its high coercivity and high remanence.

[0003] During the operation of permanent magnet motors, the permanent magnets of the motors are often subjected to a certain reverse magnetic field. Especially when the motors are running in harsh conditions, start-up failures, or strong mechanical vibrations, the controller will generate a large instantaneous current, exerting a large instantaneous reverse magnetic field on the permanent magnets. This reverse magnetic field is usually much larger than the demagnetization component in the stator magnetic field during normal operation, causing the motor to demagnetize, resulting in a decrease in motor performance or even unusable.

[0004] In recent years, the development trend of motors has been towards miniaturization and high power density, which requires motors to pursue smaller size under heavy load conditions. The operating point of the rotor permanent magnet is lower, and the risk of demagnetization of the motor increases under large load conditions, resulting in poor motor performance and inability to work normally. At the same time, the motor magnetic flux decreases and the efficiency is reduced. Summary of the invention

[0005] The main purpose of the present invention is to provide a motor rotor and a permanent magnet motor, which can improve the anti-demagnetization ability of the permanent magnet motor and enhance the motor performance.

[0006] In order to achieve the above-mentioned object, according to one aspect of the present invention, a motor rotor is provided, comprising a rotor core, a plurality of permanent magnet slots are opened on the rotor core, permanent magnets are arranged in the permanent magnet slots, under one pole, the permanent magnets comprise a first permanent magnet, a second permanent magnet, a third permanent magnet and a fourth permanent magnet, the first permanent magnet and the third permanent magnet are located on a first side of the d-axis, the second permanent magnet and the fourth permanent magnet are located on a second side of the d-axis, the third permanent magnet is located on a side of the first permanent magnet close to the d-axis, the fourth permanent magnet is located on a side of the second permanent magnet close to the d-axis, the magnetic induction coercive force of the first permanent magnet is smaller than the magnetic induction coercive force of the third permanent magnet, the magnetic induction coercive force of the second permanent magnet is smaller than the magnetic induction coercive force of the fourth permanent magnet, and in a cross section perpendicular to the central axis of the rotor core, the length of the first permanent magnet is greater than the length of the third permanent magnet, and the length of the second permanent magnet is greater than the length of the fourth permanent magnet.

[0007] Furthermore, a magnetic isolation bridge is formed between the first end of the third permanent magnet and the outer circle of the rotor, a preset interval is provided between the second end of the third permanent magnet and the d-axis, a magnetic isolation bridge is formed between the first end of the fourth permanent magnet and the outer circle of the rotor, a preset interval is provided between the second end of the fourth permanent magnet and the d-axis, a magnetic isolation bridge is formed between the first end of the first permanent magnet and the outer circle of the rotor, and a magnetic isolation bridge is formed between the first end of the second permanent magnet and the outer circle of the rotor.

[0008] Further, the first permanent magnet is parallel to the third permanent magnet, and the second permanent magnet is parallel to the fourth permanent magnet; and / or the first permanent magnet and the second permanent magnet are symmetrical about the d-axis, and the third permanent magnet and the fourth permanent magnet are symmetrical about the d-axis.

[0009] Further, in a cross section perpendicular to the central axis of the rotor core, the length of the first permanent magnet and the second permanent magnet is W1, the length of the third permanent magnet and the fourth permanent magnet is W2, and 4mm≤5W2≤W1≤21mm.

[0010] Furthermore, the magnetic induction coercive force of the first permanent magnet is Hc1, the magnetic induction coercive force of the second permanent magnet is Hc2, the magnetic induction coercive force of the third permanent magnet is Hc3, and the magnetic induction coercive force of the fourth permanent magnet is Hc4, 2.84Hc1≤Hc3≤4.55Hc1, 2.84Hc2≤Hc4≤4.55Hc2.

[0011] Furthermore, the first permanent magnet and the second permanent magnet form a V-shaped structure, and the angle of the V-shaped structure is set to A, wherein 85°≤A≤100°.

[0012] Furthermore, the third permanent magnet is provided with a first magnetic isolation groove at the second end close to the d-axis, the first magnetic isolation groove extends from the second end of the third permanent magnet to the outer circle of the rotor, and forms a magnetic isolation bridge between the outer circle of the rotor, and the fourth permanent magnet is provided with a third magnetic isolation groove at the second end close to the d-axis, the third magnetic isolation groove extends from the second end of the fourth permanent magnet to the outer circle of the rotor, and forms a magnetic isolation bridge between the outer circle of the rotor.

[0013] Furthermore, a second magnetic isolation groove is arranged on the side of the first magnetic isolation groove away from the d-axis, a magnetic isolation bridge is formed between the first end of the second magnetic isolation groove and the third permanent magnet, and a magnetic isolation bridge is formed between the second end and the outer circle of the rotor; a fourth magnetic isolation groove is arranged on the side of the third magnetic isolation groove away from the d-axis, a magnetic isolation bridge is formed between the first end of the fourth magnetic isolation groove and the fourth permanent magnet, and a magnetic isolation bridge is formed between the second end and the outer circle of the rotor.

[0014] Furthermore, in a cross section perpendicular to the central axis of the rotor core, the distance between the first permanent magnet and the third permanent magnet is L1, the distance between the second magnetic isolation groove and the third permanent magnet is L2, and 3≤L1 / L2≤4.

[0015] Furthermore, in a cross section perpendicular to the central axis of the rotor core, an angle C is included between the side of the first magnetic isolation groove away from the second magnetic isolation groove and the first permanent magnet, and an angle B is included between the side of the first magnetic isolation groove close to the second magnetic isolation groove and the third permanent magnet, and 0.8≤B / C≤1.

[0016] Furthermore, in a cross section perpendicular to the central axis of the rotor core, the first magnetic isolation groove and the second magnetic isolation groove are both rectangular grooves, the intersection of an extended line of the center line of the first magnetic isolation groove and the d-axis is a first intersection, the intersection of an extended line of the center line of the second magnetic isolation groove and the d-axis is a second intersection, the distance between the first intersection and the center of the rotor core is H1, the distance between the second intersection and the center of the rotor core is H2, 40mm≤H1≤H2≤46mm.

[0017] Furthermore, in a cross section perpendicular to the central axis of the rotor core, the width of the first magnetic isolation groove at one end close to the outer circle of the rotor along the circumferential direction is S1, and the width of the second end of the second magnetic isolation groove along the circumferential direction is S2, 1.1mm≤S1≤1.25S2≤1.5mm.

[0018] Furthermore, the width of the magnetic isolation bridge between the first magnetic isolation groove and the second magnetic isolation groove on the side close to the outer circle of the rotor is K, 0.6σ≤K≤0.8σ, where σ is the air gap width of the motor, 0.8mm≤σ≤1.5mm.

[0019] Furthermore, in a cross section perpendicular to the central axis of the rotor core, the first magnetic isolation slot includes a first slot segment and a second slot segment, the first slot segment is arranged corresponding to the end of the third permanent magnet, the second slot segment is located on the side of the third permanent magnet close to the d-axis, and the width of the first slot segment is smaller than the width of the second slot segment.

[0020] Furthermore, the length of the first slot segment is L3, the length of the second slot segment is L4, 3.4σ≤L4≤3.7σ, 2.3L4<L3<2.5L4, wherein σ is the air gap width of the motor, 0.8mm<σ<1.5mm.

[0021] Further, the first magnetic isolation groove and the third magnetic isolation groove are symmetrical about the d-axis, and the second magnetic isolation groove and the fourth magnetic isolation groove are symmetrical about the d-axis.

[0022] Furthermore, the corners of the first magnetic isolation groove, the second magnetic isolation groove, the third magnetic isolation groove and the fourth magnetic isolation groove are rounded, and the radius of the rounded corner is R1, 0.2mm≤R1≤0.4mm.

[0023] Further, the magnetization directions of the first permanent magnet, the second permanent magnet, the third permanent magnet and the fourth permanent magnet are the same; and / or, in a cross section perpendicular to the central axis of the rotor core, the width of the first permanent magnet, the second permanent magnet, the third permanent magnet and the fourth permanent magnet is t, 2.3mm≤t≤2.5mm.

[0024] According to another aspect of the present invention, a permanent magnet motor is provided, comprising a motor rotor and a motor stator. The motor rotor is the motor rotor described above, and the motor stator is located at the outer periphery of the motor rotor.

[0025] According to the technical solution of the present invention, the motor rotor includes a rotor core, a plurality of permanent magnet slots are provided on the rotor core, permanent magnets are arranged in the permanent magnet slots, and under one pole, the permanent magnets include a first permanent magnet, a second permanent magnet, a third permanent magnet and a fourth permanent magnet, the first permanent magnet and the third permanent magnet are located on a first side of the d-axis, the second permanent magnet and the fourth permanent magnet are located on a second side of the d-axis, the third permanent magnet is located on a side of the first permanent magnet close to the d-axis, the fourth permanent magnet is located on a side of the second permanent magnet close to the d-axis, the magnetic induction coercive force of the first permanent magnet is smaller than the magnetic induction coercive force of the third permanent magnet, the magnetic induction coercive force of the second permanent magnet is smaller than the magnetic induction coercive force of the fourth permanent magnet, and in a cross section perpendicular to the central axis of the rotor core, the length of the first permanent magnet is greater than the length of the third permanent magnet, and the length of the second permanent magnet is greater than the length of the fourth permanent magnet. The permanent magnet motor optimizes the positional relationship among the first permanent magnet, the second permanent magnet, the third permanent magnet and the fourth permanent magnet and the relationship between the magnetic induction coercive force. Since the third permanent magnet and the fourth permanent magnet are arranged near the outer cylindrical end of the rotor and the coercive force is greater than that of the first permanent magnet and the second permanent magnet, the irreversible demagnetization phenomenon caused by the demagnetization magnetic field of the first permanent magnet and the second permanent magnet can be reduced, and the anti-demagnetization ability of the first permanent magnet and the second permanent magnet can be improved. The length of the first permanent magnet and the second permanent magnet is greater than that of the third permanent magnet and the fourth permanent magnet. It can ensure that the protective effect of the first permanent magnet and the second permanent magnet on the third permanent magnet and the fourth permanent magnet can be effectively implemented, ensure the output of the magnetomotive force of the magnet, prevent the first permanent magnet and the second permanent magnet from losing magnetism due to the demagnetization magnetic field, and control the cost of magnetic steel materials. Through the above-mentioned structural design, the anti-demagnetization ability of the first permanent magnet and the second permanent magnet can be increased, the demagnetization magnetic field component of the armature magnetic field in the magnetization direction of the third permanent magnet and the fourth permanent magnet can be reduced, the anti-demagnetization ability of the third permanent magnet and the fourth permanent magnet can be improved, the motor efficiency can be improved, and the motor performance can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0027] Figure 1 A schematic diagram showing the structure of a motor rotor according to an embodiment of the present invention is shown;

[0028] Figure 2 A diagram showing the size structure of a motor rotor according to an embodiment of the present invention;

[0029] Figure 3A schematic diagram of magnetizing a motor rotor according to an embodiment of the present invention is shown;

[0030] Figure 4 A schematic structural diagram of a permanent magnet motor according to an embodiment of the present invention is shown;

[0031] Figure 5 A schematic diagram showing a demagnetization state of a permanent magnet motor according to an embodiment of the present invention; and

[0032] Figure 6 A schematic diagram of the current required for demagnetization of a permanent magnet motor according to an embodiment of the present invention is shown.

[0033] The above drawings include the following reference numerals:

[0034] 1. Rotor core; 2. Permanent magnet slot; 3. First permanent magnet; 4. Second permanent magnet; 5. Third permanent magnet; 6. Fourth permanent magnet; 7. Magnetic isolation bridge; 8. First magnetic isolation slot; 9. Second magnetic isolation slot; 10. Third magnetic isolation slot; 11. Fourth magnetic isolation slot; 12. First slot segment; 13. Second slot segment; 14. Motor stator. DETAILED DESCRIPTION

[0035] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0036] See also Figures 1 to 6 As shown, according to an embodiment of the present invention, a motor rotor includes a rotor core 1, a plurality of permanent magnet slots 2 are provided on the rotor core 1, permanent magnets are arranged in the permanent magnet slots 2, and under one pole, the permanent magnets include a first permanent magnet 3, a second permanent magnet 4, a third permanent magnet 5 and a fourth permanent magnet 6, the first permanent magnet 3 and the third permanent magnet 5 are located on a first side of the d-axis, the second permanent magnet 4 and the fourth permanent magnet 6 are located on a second side of the d-axis, the third permanent magnet 5 is located on a side of the first permanent magnet 3 close to the d-axis, the fourth permanent magnet 6 is located on a side of the second permanent magnet 4 close to the d-axis, the magnetic induction coercive force of the first permanent magnet 3 is smaller than the magnetic induction coercive force of the third permanent magnet 5, the magnetic induction coercive force of the second permanent magnet 4 is smaller than the magnetic induction coercive force of the fourth permanent magnet 6, and in a cross section perpendicular to the central axis of the rotor core 1, the length of the first permanent magnet 3 is greater than the length of the third permanent magnet 5, and the length of the second permanent magnet 4 is greater than the length of the fourth permanent magnet 6.

[0037] The permanent magnet motor optimizes the positional relationship between the first permanent magnet 3, the second permanent magnet 4, the third permanent magnet 5 and the fourth permanent magnet 6 and the relationship between the magnetic induction coercive force. Since the third permanent magnet 5 and the fourth permanent magnet 6 are arranged near the outer end of the rotor and the coercive force is greater than the coercive force of the first permanent magnet 3 and the second permanent magnet 4, the irreversible demagnetization phenomenon caused by the first permanent magnet 3 and the second permanent magnet 4 under the influence of the demagnetization magnetic field can be reduced, and the anti-demagnetization ability of the first permanent magnet 3 and the second permanent magnet 4 can be improved. The length of the first permanent magnet 3 and the second permanent magnet 4 is greater than the length of the third permanent magnet 5 and the fourth permanent magnet 6. The degree can ensure that the protection effect of the first permanent magnet 3 and the second permanent magnet 4 on the third permanent magnet 5 and the fourth permanent magnet 6 can be effectively implemented, the magnetomotive force output of the magnet is guaranteed, and the first permanent magnet 3 and the second permanent magnet 4 are prevented from losing magnetism due to the demagnetization magnetic field and the cost of magnetic steel materials is controlled. Through the above-mentioned structural design, the anti-demagnetization ability of the first permanent magnet 3 and the second permanent magnet 4 can be increased, the demagnetization magnetic field component of the armature magnetic field in the magnetization direction of the third permanent magnet 5 and the fourth permanent magnet 6 can be reduced, the anti-demagnetization ability of the third permanent magnet 5 and the fourth permanent magnet 6 can be improved, the motor efficiency is improved, and the motor performance is improved.

[0038] In this embodiment, the positional relationship among the first permanent magnet 3, the second permanent magnet 4, the third permanent magnet 5 and the fourth permanent magnet 6 and the relationship between the magnetic induction coercive force are limited at the same time, so that the two can interact with each other, which can not only improve the anti-demagnetization performance of the permanent magnet from the perspective of the coercive force of the permanent magnet, but also change the intensity of the demagnetization magnetic field by utilizing the relationship between the lengths, thereby improving the anti-demagnetization ability of the permanent magnet, thereby greatly improving the anti-demagnetization ability of the permanent magnet in terms of comprehensive performance.

[0039] This design, by using permanent magnets with different magnetic induction coercivity, can effectively meet the motor's operating requirements at different temperatures. Especially in high-temperature environments, it can significantly improve the motor's magnetic stability and reduce the risk of permanent magnet demagnetization. It is suitable for electric vehicles, industrial equipment and other occasions that need to operate stably in high-temperature environments. The implementation results show that this design can effectively improve the motor's magnetic properties and thermal stability, greatly reducing the risk of demagnetization of the motor at high temperatures, thereby improving the overall operating efficiency and reliability of the motor.

[0040] In response to the market demand for high power density motors, the permanent magnet operating point of this motor rotor is lower. The motor is at risk of demagnetization under high load conditions. The motor rotor can disperse the demagnetization effect of the armature magnetic field on the first and second permanent magnets, thereby improving the overall anti-demagnetization ability of the motor. While not increasing the cost of the motor, the motor power factor is improved, the motor output torque is increased, the operating current is reduced, the motor copper loss is reduced, and the motor efficiency is improved.

[0041] The application scenarios of this motor rotor include but are not limited to drive motors for electric vehicles, high-load motors in industrial production equipment, and special motor devices that need to maintain stable operation in high-temperature environments.

[0042] In one embodiment, a magnetic isolation bridge 7 is formed between the first end of the third permanent magnet 5 and the outer circle of the rotor, a preset interval is provided between the second end of the third permanent magnet 5 and the d-axis, a magnetic isolation bridge 7 is formed between the first end of the fourth permanent magnet 6 and the outer circle of the rotor, a preset interval is provided between the second end of the fourth permanent magnet 6 and the d-axis, a magnetic isolation bridge 7 is formed between the first end of the first permanent magnet 3 and the outer circle of the rotor, and a magnetic isolation bridge 7 is formed between the first end of the second permanent magnet 4 and the outer circle of the rotor.

[0043] The design of the magnetic isolation bridge 7 can effectively reduce magnetic flux leakage and optimize the magnetic field distribution, thereby improving the efficiency and power density of the motor, and is particularly suitable for electric vehicle drive motors that require high efficiency and high power density. In practical applications, the design of the magnetic isolation bridge 7 not only reduces the unnecessary loss of magnetic flux, but also significantly improves the magnetic efficiency of the motor by optimizing the magnetic flux path inside the motor, reduces the loss and temperature rise of the motor, and enables the motor to maintain a lower temperature under high load operation, thereby extending the service life of the motor.

[0044] In addition, through the above-mentioned definition, the third permanent magnet 5 is arranged on the side close to the outer circle of the rotor and away from the d-axis in the area surrounded by the first permanent magnet 3 and the outer circle of the rotor, and the fourth permanent magnet 6 is arranged on the side close to the outer circle of the rotor and away from the d-axis in the area surrounded by the second permanent magnet 4 and the outer circle of the rotor, so that a sufficient magnetic conductive channel can be left between the third permanent magnet 5 and the fourth permanent magnet 6, so that the magnetic circuit of the first permanent magnet 3 and the second permanent magnet 4 can pass smoothly through the magnetic conductive channel between the third permanent magnet 5 and the fourth permanent magnet 6, thereby improving the magnetic circuit conduction effect and improving the magnetic properties of the motor.

[0045] In one embodiment, the first permanent magnet 3 is parallel to the third permanent magnet 5, and the second permanent magnet 4 is parallel to the fourth permanent magnet 6. Along the direction from the q axis to the d axis, the third permanent magnet 5 is located outside the first permanent magnet 3 and is parallel to the first permanent magnet 3. The first permanent magnet 3 is closer to the stator reverse magnetic field. Therefore, the third permanent magnet 5 is placed outside the first permanent magnet 3 to reduce the demagnetization phenomenon of the central surface area of ​​the first permanent magnet 3 close to the air gap side. The fourth permanent magnet 6 is located outside the second permanent magnet 4 and is parallel to the second permanent magnet 4. The second permanent magnet 4 is closer to the stator reverse magnetic field. Therefore, the fourth permanent magnet 6 is placed outside the second permanent magnet 4 to reduce the demagnetization phenomenon of the central surface area of ​​the second permanent magnet 4 close to the air gap side. Through the above arrangement, the anti-demagnetization ability of the first permanent magnet 3 and the second permanent magnet 4 can be increased, the demagnetization magnetic field component of the armature magnetic field in the magnetization direction of the third permanent magnet 5 and the fourth permanent magnet can be reduced, the anti-demagnetization ability of the third permanent magnet 5 and the fourth permanent magnet 6 can be improved, and the motor efficiency can be improved.

[0046] The first permanent magnet 3 and the second permanent magnet 4 are symmetrical about the d axis, and the third permanent magnet 5 and the fourth permanent magnet 6 are symmetrical about the d axis. This symmetrical design can improve the demagnetization consistency of the third permanent magnet 5 and the fourth permanent magnet 6, improve the anti-demagnetization ability of the motor, ensure the balance of the motor during operation, reduce vibration and noise, improve the operation quality of the motor, and is suitable for precision equipment and household appliances with high requirements for vibration and noise control. Through this symmetrical permanent magnet layout, the motor can maintain good balance characteristics when rotating at high speed, effectively suppress the generation of vibration and noise, improve the comfort and reliability of the motor, and is particularly suitable for precision equipment and household appliances, such as high-end washing machines, air-conditioning compressors, precision measuring instruments, etc., which have strict requirements for low vibration and low noise during operation.

[0047] In one embodiment, in a cross section perpendicular to the central axis of the rotor core 1 , the length of the first permanent magnet 3 and the second permanent magnet 4 is W1 , the length of the third permanent magnet 5 and the fourth permanent magnet 6 is W2 , and 4mm≤5W2≤W1≤21mm.

[0048] By limiting the length relationship and length range of the first permanent magnet 3, the second permanent magnet 4, the third permanent magnet 5 and the fourth permanent magnet 6, the length settings of the first permanent magnet 3, the second permanent magnet 4, the third permanent magnet 5 and the fourth permanent magnet 6 can be within an optimal range, which can more effectively ensure that the protective effect of the first permanent magnet 3 and the second permanent magnet 4 on the third permanent magnet 5 and the fourth permanent magnet 6 can be effectively implemented, ensure the magnetomotive force output of the magnet, prevent the first permanent magnet 3 and the second permanent magnet 4 from losing magnetism due to the demagnetization magnetic field, and control the cost of magnetic steel materials.

[0049] In one embodiment, the magnetic induction coercive force of the first permanent magnet 3 is Hc1, the magnetic induction coercive force of the second permanent magnet 4 is Hc2, the magnetic induction coercive force of the third permanent magnet 5 is Hc3, and the magnetic induction coercive force of the fourth permanent magnet 6 is Hc4, 2.84Hc1≤Hc3≤4.55Hc1, 2.84Hc2≤Hc4≤4.55Hc2.

[0050] By reasonably limiting the relationship between the magnetic induction coercive force of the first permanent magnet 3 and the third permanent magnet 5 and between the second permanent magnet 4 and the fourth permanent magnet 6, the irreversible demagnetization phenomenon of the first permanent magnet 3 and the second permanent magnet 4 caused by the demagnetization magnetic field can be more effectively reduced, and the anti-demagnetization ability of the first permanent magnet 3 and the second permanent magnet 4 can be improved.

[0051] See also Figure 5As shown, when the ratio of the magnetic induction coercive force of the third permanent magnet 5 to the first permanent magnet 3 and the ratio of the magnetic induction coercive force of the fourth permanent magnet 6 to the second permanent magnet 4 are limited to the above range, the demagnetization current consumed by the demagnetization of the permanent magnet can be larger, and the demagnetization resistance is better.

[0052] By reasonably distributing the magnetic induction coercivity of permanent magnets, it is possible to reduce dependence on high magnetic induction coercivity permanent magnets while ensuring the magnetic properties of the motor, thereby reducing the manufacturing cost of the motor. It is particularly suitable for cost-sensitive industrial motors and household appliance motors.

[0053] In one embodiment, the first permanent magnet 3 and the second permanent magnet 4 form a V-shaped structure, and the included angle of the V-shaped structure is set to A, wherein 85°≤A≤100°.

[0054] This design can reduce the problem of easy demagnetization of the surface area of ​​the first permanent magnet 3 and the second permanent magnet 4 close to the center of the rotor, so that the easy demagnetization area of ​​the permanent magnet is farther away from the reverse magnetic field of the stator, thereby alleviating the effect of the reverse demagnetization magnetic field on the easy demagnetization area.

[0055] The V-shaped permanent magnet design optimizes the magnetic field distribution inside the motor, providing a more uniform magnetic field distribution, allowing the motor to generate a more uniform and stable magnetic field during operation, significantly improving the magnetic properties of the motor and reducing fluctuations during operation. This design not only improves the efficiency of the motor, but also extends the service life of the motor, providing strong technical support for the development of precision instruments and high-end electric vehicles.

[0056] In one embodiment, the third permanent magnet 5 is provided with a first magnetic isolation groove 8 at the second end close to the d-axis, the first magnetic isolation groove 8 extends from the second end of the third permanent magnet 5 to the outer circle of the rotor, and forms a magnetic isolation bridge 7 with the outer circle of the rotor, and the fourth permanent magnet 6 is provided with a third magnetic isolation groove 10 at the second end close to the d-axis, the third magnetic isolation groove 10 extends from the second end of the fourth permanent magnet 6 to the outer circle of the rotor, and forms a magnetic isolation bridge 7 with the outer circle of the rotor. The permanent magnet motor can guide the direction of the magnetic field through the first magnetic isolation groove 8 connected to the third permanent magnet 5 and the third magnetic isolation groove 10 connected to the fourth permanent magnet 6, and reduce the risk of demagnetization of the first permanent magnet 3 and the second permanent magnet 4 by guiding the direction of the magnetic circuit.

[0057] There is a magnetic steel slot gap between the third permanent magnet 5 and the permanent magnet slot 2, which is connected to the first magnetic isolation slot 8 and extends away from the third permanent magnet 5. Through this design, the magnetic field can be guided by the first magnetic isolation slot 8, thereby reducing the influence of the third permanent magnet 5 with higher magnetic induction coercive force on the first permanent magnet 3 with lower magnetic induction coercive force, thereby optimizing the motor noise. The design of the fourth permanent magnet 6 and the third magnetic isolation slot 10 is the same, and has the same effect.

[0058] The arrangement of the magnetic isolation groove and the magnetic isolation bridge 7 can accurately control the magnetic flux path inside the motor, reduce magnetic flux leakage, improve the magnetic properties and operating efficiency of the motor, effectively prevent unnecessary leakage of magnetic flux, reduce the energy consumption of the motor, and improve the reliability and service life of the motor.

[0059] In one embodiment, a second magnetic isolation groove 9 is provided on the side of the first magnetic isolation groove 8 away from the d-axis, a magnetic isolation bridge 7 is formed between the first end of the second magnetic isolation groove 9 and the third permanent magnet 5, and a magnetic isolation bridge 7 is formed between the second end and the outer circle of the rotor; a fourth magnetic isolation groove 11 is provided on the side of the third magnetic isolation groove 10 away from the d-axis, a magnetic isolation bridge 7 is formed between the first end of the fourth magnetic isolation groove 11 and the fourth permanent magnet 6, and a magnetic isolation bridge 7 is formed between the second end and the outer circle of the rotor.

[0060] The motor rotor can effectively increase the protection of the first permanent magnet 3 and the second permanent magnet 4 through the first magnetic isolation groove 8 and the second magnetic isolation groove 9, and reduce the influence of the first permanent magnet 3 and the second permanent magnet 4 on the third and fourth permanent magnets. The simultaneous arrangement of the first magnetic isolation groove 8 and the second magnetic isolation groove 9 can improve the direction of the guided magnetic field, solve the problem that the permanent magnet is easy to demagnetize near the air gap end, optimize the air gap magnetic field of the motor, make the air gap magnetic density curve more sinusoidal, reduce the motor operating current, improve the anti-demagnetization ability of the permanent magnet motor, reduce copper loss, and improve the motor efficiency.

[0061] The design of multiple magnetic isolation slots can further optimize the magnetic field distribution, reduce magnetic flux leakage, and improve the magnetic properties and operating efficiency of the motor. Through this design of multiple magnetic isolation slots, the motor can maintain a more stable and efficient operating state under extreme temperature conditions, effectively reduce magnetic flux leakage, optimize magnetic field distribution, significantly improve the magnetic properties and operating efficiency of the motor, and ensure the reliability and performance of the motor in harsh environments.

[0062] In one embodiment, in a cross section perpendicular to the central axis of the rotor core 1 , the distance between the first permanent magnet 3 and the third permanent magnet 5 is L1, the distance between the second magnetic isolation groove 9 and the third permanent magnet 5 is L2, and 3≤L1 / L2≤4.

[0063] L1 is related to L2, which can improve the mechanical strength of the rotor laminations, optimize the distribution of the rotor magnetic field, and improve the electromagnetic torque of the motor. If the ratio of L1 to L2 is too small, eddy current loss will increase. Eddy current will cause the magnet to heat up, and high temperature will cause the permanent magnet to demagnetize. Eddy current loss will also cause the motor performance to deteriorate. If the ratio is too large, the utilization rate of the permanent magnet will decrease, and it will be difficult to meet the motor performance. Setting this size can also ensure that there is a large enough air gap magnetic field in the motor air gap to meet the motor performance indicators, and increase the shunting effect of the armature reaction, increasing the overall anti-demagnetization ability of the motor.

[0064] By controlling the distance between the permanent magnet and the magnetic isolation slot, the magnetic properties of the motor can be optimized, the mechanical strength of the rotor punching can be improved, the distribution of the rotor magnetic field can be optimized, the electromagnetic torque of the motor can be improved, and the efficiency and power density of the motor can be improved. It is particularly suitable for electric vehicle drive motors and industrial equipment motors that require high efficiency and high power density. In practical applications, by accurately controlling the ratio of L1 to L2, the magnetic properties of the motor can be effectively optimized, the unnecessary loss of magnetic flux can be reduced, and the efficiency and power density of the motor can be improved.

[0065] In one embodiment, in a cross section perpendicular to the central axis of the rotor core 1, the width of the first magnetic isolation groove 8 at one end close to the outer circle of the rotor along the circumferential direction is S1, and the width of the second end of the second magnetic isolation groove 9 along the circumferential direction is S2, 1.1mm≤S1≤1.25S2≤1.5mm.

[0066] When the motor is operating at high speed, the rotor's magnetic isolation bridge 7 is subjected to great force. A narrow magnetic isolation bridge 7 is difficult to meet the rotor structural strength requirements at high speed. This design can improve the rotor structural strength on the basis of reducing magnetic leakage.

[0067] By controlling the width of the magnetic isolation slot, the magnetic field distribution can be further optimized, magnetic flux leakage can be reduced, and the magnetic performance and operating efficiency of the motor can be improved. It is particularly suitable for electric vehicles and industrial equipment motors that require high magnetic performance and high efficiency. By controlling the width of S1 and S2, the magnetic field distribution of the motor can be accurately optimized, and the unnecessary loss of magnetic flux can be reduced, thereby significantly improving the magnetic performance and operating efficiency of the motor.

[0068] In one embodiment, in a cross section perpendicular to the central axis of the rotor core 1, the first magnetic isolation groove 8 and the second magnetic isolation groove 9 are both rectangular grooves, the intersection of the extended line of the center line of the first magnetic isolation groove 8 and the d-axis is the first intersection, the intersection of the extended line of the center line of the second magnetic isolation groove 9 and the d-axis is the second intersection, the distance between the first intersection and the center of the rotor core 1 is H1, the distance between the second intersection and the center of the rotor core 1 is H2, 40mm≤H1≤H2≤46mm.

[0069] By limiting the setting positions of the first magnetic isolation groove 8 and the second magnetic isolation groove 9, the direction of the magnetic field can be effectively guided, the air gap magnetic density waveform can be improved, the magnetic flux leakage can be reduced, and the magnetic properties and operating efficiency of the motor can be improved.

[0070] In one embodiment, the width of the magnetic isolation bridge 7 between the first magnetic isolation groove 8 and the second magnetic isolation groove 9 on the side close to the outer circle of the rotor is K, 0.6σ≤K≤0.8σ, where σ is the air gap width of the motor, 0.8mm≤σ≤1.5mm. The width design of the magnetic isolation bridge 7 can effectively improve the mechanical strength of the rotor punching, optimize the rotor magnetic field distribution, and improve the magnetic properties and operating efficiency of the motor.

[0071] In one embodiment, the first magnetic isolation slot 8 includes a first slot section 12 and a second slot section 13, the first slot section 12 is arranged corresponding to the end of the third permanent magnet 5, the second slot section 13 is located on the side of the third permanent magnet 5 close to the d-axis, and the width of the first slot section 12 is smaller than the width of the second slot section 13. This design can effectively control the magnetic flux path, reduce magnetic flux leakage, improve the magnetic performance and operating efficiency of the motor, and reduce the use cost of the permanent magnet.

[0072] In one embodiment, the length of the first slot section 12 is L3, the length of the second slot section 13 is L4, 3.4σ≤L4≤3.7σ, 2.3L4<L3<2.5L4, where σ is the air gap width of the motor, 0.8mm<σ<1.5mm. Through the above definition, it can be ensured that the magnetic resistance of the first magnetic isolation slot 8 is greater than the air gap magnetic resistance, the leakage magnetic effect of the first magnetic isolation slot 8 is reduced, and the performance of the motor is excellent.

[0073] In one embodiment, in a cross section perpendicular to the central axis of the rotor core 1, the angle between the side of the first magnetic isolation groove 8 away from the second magnetic isolation groove 9 and the first permanent magnet 3 is C, and the angle between the side of the first magnetic isolation groove 8 close to the second magnetic isolation groove 9 and the third permanent magnet 5 is B, and 0.8≤B / C≤1.

[0074] This design can improve the demagnetization and leakage of the motor's magnetic steel, reduce the leakage between permanent magnets, reduce the leakage of the permanent magnets themselves, improve the utilization rate of the magnetic steel, and improve the power factor of the motor.

[0075] In one embodiment, the first magnetic isolation slot 8 and the third magnetic isolation slot 10 are symmetrical about the d-axis, and the second magnetic isolation slot 9 and the fourth magnetic isolation slot 11 are symmetrical about the d-axis. The symmetrical magnetic isolation slot design can ensure the balance of the motor during operation, improve the symmetry of the permanent magnet motor rotor, reduce torque pulsation, reduce back electromotive force harmonics, reduce the motor noise level, and improve the operation quality of the motor.

[0076] In the above-mentioned embodiments, the structures of the first magnetic isolation groove 8 and the third magnetic isolation groove 10 are exactly the same and are symmetrical about the d-axis, and the structures of the second magnetic isolation groove 9 and the fourth magnetic isolation groove 11 are exactly the same and are symmetrical about the d-axis. Therefore, in the above-mentioned embodiments, the structural design of the first magnetic isolation groove 8 can also be applied to the third magnetic isolation groove 10, and the structural design of the second magnetic isolation groove 9 can also be applied to the fourth magnetic isolation groove 11.

[0077] In one embodiment, the corners of the first magnetic isolation groove 8, the second magnetic isolation groove 9, the third magnetic isolation groove 10 and the fourth magnetic isolation groove 11 are rounded, and the radius of the rounded corner is R1, 0.2mm≤R1≤0.4mm. The rounded corner design can reduce stress concentration, reduce the magnetic field concentration effect at each corner of the magnetic steel groove, reduce the harmonic content of the air gap magnetic density, and improve the structural stability of the permanent magnet and the magnetic isolation groove.

[0078] In one embodiment, the magnetization directions of the first permanent magnet 3, the second permanent magnet 4, the third permanent magnet 5 and the fourth permanent magnet 6 are the same. The consistency of the magnetization direction and the optimization of the width of the permanent magnet can provide a more uniform magnetic field distribution, improve the magnetic properties and operating efficiency of the motor. Through this structural design, the magnetic flux of each pole can be further increased, the motor flux linkage can be increased, and the output torque and power of the motor can be further improved, which is conducive to increasing the motor reluctance torque and the weak magnetic expansion speed range.

[0079] In the cross section perpendicular to the central axis of the rotor core 1, the width of the first permanent magnet 3, the second permanent magnet 4, the third permanent magnet 5 and the fourth permanent magnet 6 is t, 2.3mm≤t≤2.5mm. By limiting the width of each permanent magnet, the difficulty of permanent magnet processing can be reduced, the processing cost can be reduced, the total cost of the motor can be reduced, and the magnetic lines of force of the magnetic steel can fully pass through the air gap to reach the stator teeth and form an interlink with the coil, which is conducive to increasing the reluctance torque of the motor and improving the power density of the motor.

[0080] By optimizing the magnetization direction and the width of the permanent magnet, the magnetic field distribution inside the motor can be significantly improved, providing a more uniform and stable magnetic field, thereby significantly improving the magnetic properties and operating efficiency of the motor.

[0081] See also Figure 6 As described above, the current required for demagnetization of the permanent magnet motor in the embodiment of the present invention is increased by 20% compared with the current required for demagnetization of the permanent magnet motor in the related art, thereby greatly improving the anti-demagnetization performance of the permanent magnet motor.

[0082] See also Figure 4 As shown, according to an embodiment of the present invention, the permanent magnet motor includes a motor rotor and a motor stator 14, wherein the motor rotor is the motor rotor mentioned above, and the motor stator 14 is located at the outer periphery of the motor rotor. The motor has the advantages of high anti-demagnetization capability, high motor torque density, and high motor efficiency.

[0083] By adopting the above-mentioned optimized motor rotor, the permanent magnet motor can significantly improve the overall performance and reliability of the motor. It is particularly suitable for electric vehicle drive systems, precision instruments and industrial equipment that require high power density, high efficiency and high reliability. It has significant economic benefits and application value, and can meet the future electric vehicles and industrial automation needs for high efficiency and high power density motors. In practical applications, this optimized permanent magnet motor can significantly improve the overall performance of electric vehicle drive systems, improve the operating efficiency and reliability of precision instruments and industrial equipment, not only reduce energy consumption and improve energy efficiency, but also provide strong technical support for future electric vehicles and industrial automation. It has significant economic benefits and broad application prospects, and can effectively promote technological progress and development in the fields of electric vehicles and industrial automation.

[0084] To sum up, the motor rotor and permanent magnet motor of the present application have not only improved the magnetic properties and operating efficiency of the motor, but also reduced the use cost of permanent magnets, enhanced the stability and reliability of the motor under extreme conditions, and provided electric vehicles, precision instruments and industrial equipment with more efficient, stable and reliable power solutions, through a series of optimized designs, including the use of permanent magnets with different magnetic induction coercive forces and lengths, and the sophisticated magnetic isolation bridge 7 and magnetic isolation slot design. It has significant economic benefits and broad application prospects, and can effectively promote technological progress and development in related fields.

[0085] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0086] 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 sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0087] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A motor rotor, characterized in that: The invention comprises a rotor core (1), wherein a plurality of permanent magnet slots (2) are provided on the rotor core (1), and permanent magnets are arranged in the permanent magnet slots (2). Under one pole, the permanent magnets comprise a first permanent magnet (3), a second permanent magnet (4), a third permanent magnet (5) and a fourth permanent magnet (6), wherein the first permanent magnet (3) and the third permanent magnet (5) are located on a first side of the d-axis, the second permanent magnet (4) and the fourth permanent magnet (6) are located on a second side of the d-axis, and the third permanent magnet (5) is located on a side of the first permanent magnet (3) close to the d-axis. The fourth permanent magnet (6) is located on the side of the second permanent magnet (4) close to the d-axis, the magnetic induction coercive force of the first permanent magnet (3) is smaller than the magnetic induction coercive force of the third permanent magnet (5), the magnetic induction coercive force of the second permanent magnet (4) is smaller than the magnetic induction coercive force of the fourth permanent magnet (6), and in a cross section perpendicular to the central axis of the rotor core (1), the length of the first permanent magnet (3) is greater than the length of the third permanent magnet (5), and the length of the second permanent magnet (4) is greater than the length of the fourth permanent magnet (6).

2. The motor rotor according to claim 1, characterized in that: A magnetic isolation bridge (7) is formed between the first end of the third permanent magnet (5) and the outer circle of the rotor, a preset interval is provided between the second end of the third permanent magnet (5) and the d-axis, a magnetic isolation bridge (7) is formed between the first end of the fourth permanent magnet (6) and the outer circle of the rotor, a preset interval is provided between the second end of the fourth permanent magnet (6) and the d-axis, a magnetic isolation bridge (7) is formed between the first end of the first permanent magnet (3) and the outer circle of the rotor, and a magnetic isolation bridge (7) is formed between the first end of the second permanent magnet (4) and the outer circle of the rotor.

3. The motor rotor according to claim 1, characterized in that: The first permanent magnet (3) is parallel to the third permanent magnet (5), and the second permanent magnet (4) is parallel to the fourth permanent magnet (6); and / or the first permanent magnet (3) and the second permanent magnet (4) are symmetrical about the d-axis, and the third permanent magnet (5) and the fourth permanent magnet (6) are symmetrical about the d-axis.

4. The motor rotor according to any one of claims 1 to 3, characterized in that: In a cross section perpendicular to the central axis of the rotor core (1), the length of the first permanent magnet (3) and the second permanent magnet (4) is W1, the length of the third permanent magnet (5) and the fourth permanent magnet (6) is W2, and 4mm≤5W2≤W1≤21mm.

5. The motor rotor according to any one of claims 1 to 3, characterized in that: The magnetic induction coercive force of the first permanent magnet (3) is Hc1, the magnetic induction coercive force of the second permanent magnet (4) is Hc2, the magnetic induction coercive force of the third permanent magnet (5) is Hc3, and the magnetic induction coercive force of the fourth permanent magnet (6) is Hc4, 2.84Hc1≤Hc3≤4.55Hc1, 2.84Hc2≤Hc4≤4.55Hc2.

6. The motor rotor according to any one of claims 1 to 3, characterized in that: The first permanent magnet (3) and the second permanent magnet (4) form a V-shaped structure, and the included angle of the V-shaped structure is set to A, wherein 85°≤A≤100°.

7. The motor rotor according to any one of claims 1 to 3, characterized in that: The third permanent magnet (5) is provided with a first magnetic isolation groove (8) at the second end close to the d-axis, and the first magnetic isolation groove (8) extends from the second end of the third permanent magnet (5) to the outer circle of the rotor, and forms a magnetic isolation bridge (7) between the outer circle of the rotor. The fourth permanent magnet (6) is provided with a third magnetic isolation groove (10) at the second end close to the d-axis, and the third magnetic isolation groove (10) extends from the second end of the fourth permanent magnet (6) to the outer circle of the rotor, and forms a magnetic isolation bridge (7) between the outer circle of the rotor.

8. The motor rotor according to claim 7, characterized in that: A second magnetic isolation groove (9) is provided on the side of the first magnetic isolation groove (8) away from the d-axis, a magnetic isolation bridge (7) is formed between the first end of the second magnetic isolation groove (9) and the third permanent magnet (5), and a magnetic isolation bridge (7) is formed between the second end and the outer circle of the rotor; a fourth magnetic isolation groove (11) is provided on the side of the third magnetic isolation groove (10) away from the d-axis, a magnetic isolation bridge (7) is formed between the first end of the fourth magnetic isolation groove (11) and the fourth permanent magnet (6), and a magnetic isolation bridge (7) is formed between the second end and the outer circle of the rotor.

9. The motor rotor according to claim 8, characterized in that: In a cross section perpendicular to the central axis of the rotor core (1), the distance between the first permanent magnet (3) and the third permanent magnet (5) is L1, and the distance between the second magnetic isolation groove (9) and the third permanent magnet (5) is L2, 3≤L1 / L2≤4.

10. The motor rotor according to claim 8, characterized in that: In a cross section perpendicular to the central axis of the rotor core (1), an angle C is formed between the side of the first magnetic isolation groove (8) away from the second magnetic isolation groove (9) and the first permanent magnet (3), and an angle B is formed between the side of the first magnetic isolation groove (8) close to the second magnetic isolation groove (9) and the third permanent magnet (5), and 0.8≤B / C≤1.

11. The motor rotor according to claim 8, characterized in that: In a cross section perpendicular to the central axis of the rotor core (1), the first magnetic isolation groove (8) and the second magnetic isolation groove (9) are both rectangular grooves, the intersection of an extension of the center line of the first magnetic isolation groove (8) and the d-axis is the first intersection, the intersection of an extension of the center line of the second magnetic isolation groove (9) and the d-axis is the second intersection, the distance between the first intersection and the center of the rotor core (1) is H1, the distance between the second intersection and the center of the rotor core (1) is H2, 40mm≤H1≤H2≤46mm.

12. The motor rotor according to claim 8, characterized in that: In a cross section perpendicular to the central axis of the rotor core (1), the width of the first magnetic isolation groove (8) at one end close to the outer circle of the rotor in the circumferential direction is S1, and the width of the second end of the second magnetic isolation groove (9) in the circumferential direction is S2, 1.1mm≤S1≤1.25S2≤1.5mm.

13. The motor rotor according to claim 8, characterized in that: The width of the magnetic isolation bridge (7) between the first magnetic isolation groove (8) and the second magnetic isolation groove (9) on the side close to the outer circle of the rotor is K, 0.6σ≤K≤0.8σ, where σ is the air gap width of the motor, 0.8mm≤σ≤1.5mm.

14. The motor rotor according to claim 7, characterized in that: In a cross section perpendicular to the central axis of the rotor core (1), the first magnetic isolation slot (8) comprises a first slot section (12) and a second slot section (13), the first slot section (12) being arranged corresponding to the end of the third permanent magnet (5), the second slot section (13) being located on a side of the third permanent magnet (5) close to the d-axis, and the width of the first slot section (12) being smaller than the width of the second slot section (13).

15. The motor rotor according to claim 14, characterized in that: The length of the first slot section (12) is L3, the length of the second slot section (13) is L4, 3.4σ≤L4≤3.7σ, 2.3L4<L3<2.5L4, wherein σ is the air gap width of the motor, 0.8mm<σ<1.5mm.

16. The motor rotor according to any one of claims 8 to 13, characterized in that: The first magnetic isolation groove (8) and the third magnetic isolation groove (10) are symmetrical about the d-axis, and the second magnetic isolation groove (9) and the fourth magnetic isolation groove (11) are symmetrical about the d-axis.

17. The motor rotor according to claim 8, characterized in that: The corners of the first magnetic isolation groove (8), the second magnetic isolation groove (9), the third magnetic isolation groove (10) and the fourth magnetic isolation groove (11) are rounded, and the radius of the rounded corner is R1, 0.2mm≤R1≤0.4mm.

18. The motor rotor according to any one of claims 1 to 3, characterized in that: The magnetization directions of the first permanent magnet (3), the second permanent magnet (4), the third permanent magnet (5) and the fourth permanent magnet (6) are the same; and / or, in a cross section perpendicular to the central axis of the rotor core (1), the widths of the first permanent magnet (3), the second permanent magnet (4), the third permanent magnet (5) and the fourth permanent magnet (6) are t, and 2.3 mm ≤ t ≤ 2.5 mm.

19. A permanent magnet motor, comprising a motor rotor and a motor stator (14), characterized in that: The motor rotor is the motor rotor according to any one of claims 1 to 18, and the motor stator (14) is located at the outer periphery of the motor rotor.

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