Motor rotor and permanent magnet motor

Abstract

The utility model relates to the technical field of motors, in particular to a motor rotor and a permanent magnet motor. The motor rotor comprises a rotor body, a plurality of magnetic steel groups are uniformly arranged in the circumferential direction in the rotor body, and the magnetic steel groups are arranged corresponding to magnetic poles of the rotor body; each magnetic steel group comprises at least two magnetic steel units, and the magnetic steel units are sequentially arranged along the radial direction of the rotor body; each magnetic steel unit comprises two sub magnetic steels which are arranged at an included angle, the distance between the first ends of the two sub magnetic steels is greater than the distance between the second ends of the two sub magnetic steels, the first ends of the sub magnetic steels are one ends far away from the center of the rotor body, and the second ends of the sub magnetic steels are one ends close to the center of the rotor body; the coercive forces of the magnetic steel units in the magnetic steel group are different; according to the motor rotor provided by the utility model, the overall heat dissipation effect of the magnetic steel is good, the space of the motor rotor is optimized, and the anti-demagnetization capability of a motor is improved.

Description

Technical Field

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

[0002] The permanent magnets embedded in the rotor of a permanent magnet synchronous motor provide the rotor magnetic field, which interacts with the stator magnetic field to output power and torque. The electromagnetic torque of a permanent magnet synchronous motor is composed of permanent magnet torque and reluctance torque.

[0003] For permanent magnet synchronous motor rotors, existing permanent magnet synchronous motor rotors are generally only provided with a single layer of magnetic steel in the radial direction, which not only makes the overall heat dissipation effect of the magnetic steel poor, but also only provides a single layer of magnetic steel, which will make the coercive force of the magnetic steel of each pole of the motor the same, which is not conducive to improving the anti-demagnetization ability of the motor. Utility Model Content

[0004] In view of the above shortcomings of the prior art, the purpose of the present invention is to provide a motor rotor and a permanent magnet motor, which not only improves the overall heat dissipation effect of the magnetic steel, but also optimizes the space of the motor rotor and improves the anti-demagnetization ability of the motor.

[0005] To achieve the above-mentioned and other related purposes, the present invention provides a motor rotor, comprising:

[0006] A rotor body, wherein a plurality of magnetic steel groups are evenly arranged in a circumferential direction within the rotor body, and each magnetic steel group is arranged corresponding to a magnetic pole of the rotor body;

[0007] Each of the magnetic steel groups includes at least two magnetic steel units, and each of the magnetic steel units is arranged in sequence along the radial direction of the rotor body;

[0008] Each of the magnetic steel units includes two sub-magnets arranged at an angle, the spacing between the first ends of the two sub-magnets is greater than the spacing between the second ends of the two sub-magnets, the first end of the sub-magnet is the end away from the center of the rotor body, and the second end is the end close to the center of the rotor body; and the coercive force of each magnetic steel unit in the magnetic steel group is different.

[0009] In one embodiment of the present invention, the rotor body includes a plurality of magnetic steel slots, and each of the sub-magnetic steels is disposed in the magnetic steel slot in a one-to-one correspondence;

[0010] There is a gap between the two ends of the magnetic steel slot and the sub-magnetic steel, and the gap is filled with a non-magnetic conductive structure for fixing the sub-magnetic steel.

[0011] In one embodiment of the present invention, the magnetic steel unit close to the center of the rotor body is larger in size than the magnetic steel unit far from the center of the rotor body; the size includes thickness and / or length.

[0012] In one embodiment of the present invention, each of the sub-magnets is square in shape.

[0013] In one embodiment of the present invention, the coercive force of each of the sub-magnetic steels is greater than 500 kA / m.

[0014] In one embodiment of the present invention, the angle between the sub-magnets of each magnetic steel unit and the radial bisector of the corresponding magnetic pole is between 30° and 70°.

[0015] In one embodiment of the present invention, the magnetic steel units in the same magnetic steel group are arranged non-parallel, and the opening of the magnetic steel unit close to the center of the rotor body is smaller than the opening of the magnetic steel unit far from the center of the rotor body.

[0016] In one embodiment of the present invention, the distance between the two sub-magnetic steels of the magnetic steel unit located in the inner layer is smaller than the distance between the two sub-magnetic steels of the magnetic steel unit located in the outer layer.

[0017] In one embodiment of the present invention, each of the magnetic steel units is symmetrical about the center of the rotor body, and the two sub-magnets of each magnetic steel unit are symmetrically arranged about the radial bisector of the magnetic pole.

[0018] To achieve the above-mentioned purpose and other related purposes, the utility model provides a permanent magnet motor, including the motor rotor.

[0019] In summary, the present invention can achieve more efficient and uniform magnetic field conversion through the radial arrangement of multi-layer magnetic steel units, making the magnetic field distribution more concentrated, thereby improving the magnetic resistance and efficiency of the motor; the multi-layer magnetic steel unit structure helps to disperse the heat generated by the magnetic steel, avoid local overheating, and at the same time enhance the heat dissipation capacity, keeping the motor running at the optimal operating temperature; the two sub-magnets of each magnetic steel unit are arranged at an angle, which reduces the friction between the rotor and the stator, reduces the noise and vibration of the machine, and is conducive to improving the running smoothness of the motor; at the same time, due to the different coercive forces of multiple magnetic steel units in each magnetic pole, the anti-demagnetization ability of the motor is improved, which helps to improve the overall performance of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1This is a schematic diagram of the motor rotor structure in an optional embodiment of the present utility model;

[0022] Figure 2 This is a schematic structural diagram of three sub-magnets in an optional embodiment of the present utility model;

[0023] Figure 3 This is a schematic structural diagram of each magnetic steel group having two magnetic steel units in an optional embodiment of the present invention;

[0024] Component number explanation: rotor body 100 , magnetic steel group 10 , magnetic pole 101 , magnetic steel unit 11 , sub-magnetic steel 111 , first end 1111 , second end 1112 , magnetic steel slot 112 , radial bisector M. DETAILED DESCRIPTION

[0025] The following describes the implementation of the present invention through specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation methods. The details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following examples and the features in the examples can be combined with each other unless there is a conflict. It should also be understood that the terms used in the examples of the present invention are for the purpose of describing specific implementation methods, not for the purpose of limiting the scope of protection of the present invention. The test methods for which specific conditions are not specified in the following examples are generally carried out under conventional conditions or under the conditions recommended by the manufacturers.

[0026] See also Figure 1-3 . It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of this utility model. Therefore, they have no substantive technical significance. Any modification of the structure, change in the proportional relationship or adjustment of the size should still fall within the scope of the technical content disclosed by this utility model without affecting the efficacy and purpose that can be achieved by this utility model. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of this utility model. Changes or adjustments in their relative relationships should also be regarded as the scope of the implementation of this utility model without substantially changing the technical content.

[0027] When numerical ranges are given in the examples, it should be understood that, unless otherwise specified herein, both endpoints of each numerical range and any value between the endpoints may be used. Unless otherwise defined, all technical and scientific terms used in this utility model are consistent with the prior art as understood by those skilled in the art and the description of this utility model. Any prior art methods, equipment, and materials similar or equivalent to those described in the examples of this utility model may also be used to implement this utility model.

[0028] See also Figure 1 The present invention provides a motor rotor, comprising a rotor body 100; a plurality of magnetic steel groups 10 are evenly arranged in the circumferential direction of the rotor body 100, and each magnetic steel group 10 is arranged corresponding to a magnetic pole 101 of the rotor body 100;

[0029] Each magnetic steel group 10 includes at least two magnetic steel units 11, and each magnetic steel unit 11 is arranged sequentially along the radial direction of the rotor body 100, and each magnetic steel unit 11 is symmetrical about the center of the rotor body 100;

[0030] Each of the magnetic steel units 11 includes two sub-magnets 111 arranged at an angle. The distance between the first ends 1111 of the two sub-magnets 111 is greater than the distance between the second ends 1112 of the two sub-magnets 111. The first end 1111 of the sub-magnet 111 is the end away from the center 100 of the rotor body, and the second end 1112 is the end close to the center 100 of the rotor body. As a result, each of the magnetic steel units 11 is V-shaped or C-shaped. Each of the V-shaped or C-shaped magnetic steel units 11 has an opening, that is, the opening direction of the magnetic steel unit 11 is away from the center of the rotor body 100, and the coercive force of each magnetic steel unit 11 in the magnetic steel group 10 is different.

[0031] It should be noted that the magnets in this case are all made of coercive material, such as neodymium iron boron, cobalt samarium, steel, or iron-nickel alloy magnets. The magnet groups 10 in this case are arranged along the circumference of the rotor body 100, alternating between north and south poles, and the number of magnet groups 10 is an even number. The coercive force of a magnet refers to the material's ability to resist demagnetization, or its ability to retain its magnetism after the external magnetic field disappears. The coercive force of a motor's magnets is a key performance indicator, directly impacting its efficiency and stability. In this case, by making the coercive forces of each magnetic steel unit 11 in the magnetic steel group 10 different, a non-uniform distribution of the magnetic field inside the rotor can be achieved, which helps to improve the torque output and operating efficiency of the motor. In this case, the sub-magnets 111 with different coercive forces have different sensitivities to temperature. The reasonable configuration of this case optimizes the temperature distribution inside the motor, reduces the generation of hot spots, and thus improves the thermal stability and reliability of the motor. Although high-coercive force magnetic steel can provide better performance, the cost is also relatively high. In this case, by layering sub-magnets 111 with different coercive forces, it is possible to control costs while ensuring performance and achieve optimal economic benefits. By varying the coercive forces of the magnetic steel units 11 in different magnetic steel slots 112 and combining them with multiple V-shaped magnetic steel slots 111, this case greatly increases the space for motor optimization. Under the condition of the same magnetic steel cost, the anti-demagnetization ability of the sub-magnets 111 is improved. Similarly, under the condition of the same anti-demagnetization ability, the manufacturing cost of the sub-magnets 111 is reduced.

[0032] Furthermore, each of the magnetic steel groups 10 includes at least two magnetic steel units 11, and each of the magnetic steel units 11 is V-shaped or C-shaped or other shapes that meet the characteristic requirements of this case. Among the multiple magnetic steel units 11 of each of the magnetic steel groups 10, at least one of the magnetic steel units 11 is V-shaped or at least one of the magnetic steel units 11 is C-shaped, that is, V-shaped magnetic steel units 11 and C-shaped magnetic steel units 11 may exist in a magnetic steel group 10 at the same time, so that magnetic steel units 11 of different shapes can be arranged according to actual needs.

[0033] In this case, each of the magnetic steel groups 10 includes at least two magnetic steel units 11, such as Figure 3 As shown, each of the magnetic steel groups 10 includes two magnetic steel units 11; Figure 1 As shown, each magnetic steel group 10 includes three magnetic steel units 11 , that is, each magnetic steel group 10 in this embodiment may include two magnetic steel units 11 , three magnetic steel units 11 , or more magnetic steel units 11 .

[0034] like Figure 2 As shown, the magnetic pole 101 of the rotor body 100 is provided with three layers of magnetic steel units 11, as shown in FIG. Figure 2The figure shows a schematic structural diagram of the sub-magnetic steel 111 in the three-layer magnetic steel unit 11. The three-layer magnetic steel unit 11 is divided into layer A, layer B and layer C, wherein layer C is closer to the center of the rotor body 100, layer A is farther away from the center of the rotor body 100, and layer B is located between layer A and layer C.

[0035] Further, such as Figure 1-2 As shown, in this case, the coercive forces of the multiple magnetic steel units 11 in each magnetic pole 101 are different. Specifically, as shown in Table 1 below, under the conditions of maintaining the same current, voltage and motor temperature, a motor with three layers of magnetic steel units 11 having the same coercive force and a motor with three layers of magnetic steel units 11 having different coercive forces are adopted, and the average value of the sum of the different coercive force values ​​of the three layers of magnetic steel units 11 is the same as the coercive force value of the three layers of magnetic steel units 11 having the same coercive force; through comparison, it can be seen that the motor's anti-demagnetization ability is improved and the demagnetization ratio is reduced by adopting the motor with three layers of magnetic steel units 11 having different coercive forces.

[0036]

[0037] Table 1

[0038] In this case, each of the magnetic steel units 11 includes two sub-magnets 111 arranged at an angle, and the opening direction of the magnetic steel unit 11 is away from the center of the rotor body 100. For example, each magnetic steel unit 11 is V-shaped, and the opening of the magnetic steel unit 11 is also a V-shaped opening, which can achieve more efficient magnetic field conversion and energy transfer, making the magnetic field distribution more concentrated, thereby improving the magnetic resistance and efficiency of the motor; at the same time, the high linear magnetic characteristics of the V-shaped magnetic steel unit 11 also help the motor achieve a higher speed and output power, further improving the overall efficiency of the equipment; at the same time, the rotor of the V-shaped magnetic steel unit 11 reduces the friction between the rotor and the stator, thereby The noise and vibration of the machine are reduced, which is beneficial to improving the running stability of the motor; the rotor of the V-shaped magnetic steel unit 11 has the advantage of high torque density, so that the motor can generate greater torque under the same current input; at the same time, the V-shaped magnetic steel unit 11 of this case is suitable for the high-speed new energy vehicle motor requirements, and the V-shaped magnetic steel unit 11 is made into an embedded structure, which has strength advantages; and the magnetic steel is made into a square shape, which is easy to prepare the magnetic steel; in terms of electromagnetics, the V-shaped magnetic steel unit 11 has the advantages of high salient pole ratio, high torque power, low torque pulsation, and easy optimization; at the same time, arranging multiple layers of magnetic steel units 11 along the radial direction can improve the overall heat dissipation efficiency of the magnetic steel 11.

[0039] In this embodiment, the magnetic steel units 11 are arranged radially. The coercive forces of the magnetic steel units 11 within different magnetic steel slots 112 within a stack of cores vary. Each magnetic pole 101 of the motor rotor in this embodiment is arranged with three layers of magnetic steel units 11. By varying the coercive forces of the magnetic steel within different magnetic steel slots 112 and combining multiple V-shaped magnetic steel slots 112, this embodiment significantly increases the space available for motor optimization, reduces motor costs, and makes the optimized motor more resistant to demagnetization.

[0040] See also Figure 1 As an optional embodiment of the present invention, the rotor body 100 includes a plurality of magnetic steel slots 112, and each of the sub-magnetic steels 111 is disposed in the magnetic steel slot 112 in a one-to-one correspondence;

[0041] There is a gap between the two ends of the magnetic steel slot 112 and the sub-magnetic steel 111 , and the gap is filled with a non-magnetic conductive structure that fixes the sub-magnetic steel 111 .

[0042] It should be noted that each sub-magnet 111 described in this case occupies a separate magnetic steel slot 112; in order to avoid demagnetization of the parts of the sub-magnet 111 close to the two ends of the magnetic steel slot 112, this case creates a gap between the two ends of the magnetic steel slot 112 and the corresponding sub-magnet 111, and fills the gap with a non-magnetic conductive structure. This can, on the one hand, increase the mechanical strength of the motor rotor, and on the other hand, improve the stability of the sub-magnet 111 in the magnetic steel slot 112, thereby avoiding displacement or sliding.

[0043] See also Figure 2 As an optional embodiment of the present invention, the magnetic steel unit 11 close to the center of the rotor body 100 is larger in size than the magnetic steel unit 11 away from the center of the rotor body 100; the size includes thickness and / or length.

[0044] It should be noted that the length dimension refers to Figure 1 As shown, the length and thickness directions of the sub-magnetic steel 11 are perpendicular to the length direction, while the width direction of the sub-magnetic steel 11 is the axial direction of the rotor body 100. The width direction of the sub-magnetic steel 11 is perpendicular to the length and thickness directions. Due to the shape restriction of the rotor punching where each magnetic pole 101 is located, in this case, the magnetic steel unit 11 close to the center of the rotor body 100 is larger in size than the magnetic steel unit 11 away from the center of the rotor body 100. This allows more magnetic steel units 11 to be arranged at each magnetic pole 101, thereby increasing the total coercive force value of each pole and thus improving the anti-demagnetization capability of the motor.

[0045] See also Figure 2 As an optional embodiment of the present invention, each of the sub-magnetic steels 111 is square in shape.

[0046] It should be noted that the square-shaped sub-magnetic steel 111 is easier to process and assemble than magnets of other shapes, which helps to reduce production costs and improve production efficiency.

[0047] See also Figure 1 As an optional embodiment of the present invention, the coercive force of each of the sub-magnetic steels 111 is greater than 500 kA / m.

[0048] It should be noted that a specific numerical threshold is set for the coercive force of the sub-magnet 111, for example, greater than 500kA / m. The magnitude of the coercive force determines the thickness of the magnet. Magnets with high coercive force can be designed to be thinner, thereby helping to reduce the size and weight of the entire motor rotor, while improving the energy efficiency of the motor. In addition, coercive force is an important physical quantity that measures the ability of a magnet to resist demagnetization. It determines the ability of a magnet to maintain its original magnetism under the action of a reverse magnetic field. For a motor, the level of coercive force directly affects the performance and stability of the motor. If the coercive force of the magnet is too low, then during the operation of the motor, due to temperature changes or the influence of an external magnetic field, the magnet may demagnetize, resulting in a decrease in motor performance or even failure; therefore, the coercive force of each of the sub-magnets 111 of the motor rotor in this case is greater than 500kA / m.

[0049] As an optional embodiment of the present invention, the coercive force of each sub-magnetic steel 111 of the motor rotor in this case is less than 2000 kA / m, so as to avoid cost waste caused by excessive coercive force.

[0050] See also Figure 1 As an optional embodiment of the present invention, the angle between the sub-magnetic steel 111 of each magnetic steel unit 11 and the radial bisector M of the corresponding magnetic pole is between 30° and 70°.

[0051] It should be noted that each of the magnetic steel units 11 is symmetrical about the center of the rotor body 100, and the two sub-magnets 111 of each magnetic steel unit 11 are symmetrical about the radial bisector M of the motor rotor at the magnetic steel unit 11. The radial bisector M passes through the center of the rotor body 100 and faces the radial direction of the rotor body 100. In this embodiment, the angle between the sub-magnets 111 of each magnetic steel unit 11 and the radial bisector M of the corresponding magnetic pole is set between 30° and 70°. Figure 1As shown, that is, 70°≥a2≥a1≥30°, that is, the angle between the two sub-magnets 111 of the magnetic steel unit 11 is between 60° and 140°, the angle between the two sub-magnets 111 of the third-layer magnetic steel unit 11 is greater than or equal to the angle between the two sub-magnets 111 of the second-layer magnetic steel unit 11, and the angle between the two sub-magnets 111 of the second-layer magnetic steel unit 11 is greater than or equal to the angle between the two sub-magnets 111 of the third-layer magnetic steel unit 11. Such a constraint setting can effectively improve the output torque of the motor, sort out the magnetic circuit, reduce the torque pulsation of the motor, and improve the performance of the motor.

[0052] See also Figure 1 As an optional embodiment of the present invention, the magnetic steel units 11 in the same magnetic steel group 10 are not arranged in parallel, and the opening of the magnetic steel unit 11 close to the center of the rotor body 100 is smaller than the opening of the magnetic steel unit 11 away from the center of the rotor body 100.

[0053] It should be noted that when the angle between the two sub-magnets 111 of each magnetic steel unit 11 is between 30° and 70°, the magnetic steel units 11 in the same magnetic steel group 10 are not arranged in parallel, and the opening of the magnetic steel unit 11 close to the center of the rotor body 100 is smaller than the opening of the magnetic steel unit 11 away from the center of the rotor body 100. On the one hand, it is beneficial to the specific structural arrangement of the motor rotor, and on the other hand, it can obtain the largest possible power torque, thereby facilitating the improvement of motor performance.

[0054] See also Figure 1 As an optional embodiment of the present invention, the distance between the two sub-magnets 111 of the magnetic steel unit 11 located in the inner layer is smaller than the distance between the two sub-magnets 111 of the magnetic steel unit 11 located in the outer layer, which is beneficial to improving the strength of the high-speed motor rotor.

[0055] See also Figure 1 As an optional embodiment of the present invention, the two sub-magnets 111 of each magnetic steel unit 11 are symmetrically arranged about the radial bisector M of the magnetic pole 101, thereby improving the sinusoidality of the motor rotor magnetic field and improving the motor performance.

[0056] See also Figure 1 As an optional embodiment of the present invention, the two sub-magnets 111 of each magnetic steel unit 11 are symmetrically arranged about the radial center line of the magnetic pole 101, thereby optimizing the magnetic circuit of each magnetic pole 101, improving the motor output torque, and reducing torque pulsation.

[0057] See also Figure 1As an optional embodiment of the present invention, among the multiple magnetic steel units 11 in the same magnetic steel group 10, the coercive force difference between two adjacent magnetic steel units 11 is greater than a preset value. For example, the preset value can be set between 20kA / m and 200kA / m.

[0058] The motor rotor described in this case can be used not only in oil-cooled motors, but also in water-cooled and air-cooled motors. It is also applicable to high-voltage motors above 600V and low-voltage motors below 500V.

[0059] See also Figure 1 The utility model provides a permanent magnet motor, including the motor rotor, which is beneficial to improving the overall performance of the permanent magnet motor.

[0060] In summary, the utility model effectively overcomes some practical problems in the prior art and thus has high utilization value and use significance.

[0061] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed in the present invention are intended to be covered by the claims of the present invention.

Claims

1. A motor rotor, characterized in that: include: A rotor body, wherein a plurality of magnetic steel groups are evenly arranged in a circumferential direction within the rotor body, and each magnetic steel group is arranged corresponding to a magnetic pole of the rotor body; Each of the magnetic steel groups includes at least two magnetic steel units, and each of the magnetic steel units is arranged in sequence along the radial direction of the rotor body; Each of the magnetic steel units includes two sub-magnets arranged at an angle, the spacing between the first ends of the two sub-magnets is greater than the spacing between the second ends of the two sub-magnets, the first end of the sub-magnet is the end away from the center of the rotor body, and the second end is the end close to the center of the rotor body; and the coercive force of each magnetic steel unit in the magnetic steel group is different.

2. The motor rotor according to claim 1, characterized in that: The rotor body includes a plurality of magnetic steel slots, and each of the sub-magnetic steels is arranged in the magnetic steel slot in a one-to-one correspondence; There is a gap between the two ends of the magnetic steel slot and the sub-magnetic steel, and the gap is filled with a non-magnetic conductive structure for fixing the sub-magnetic steel.

3. The motor rotor according to claim 1, characterized in that: The magnetic steel unit close to the center of the rotor body is larger in size than the magnetic steel unit far from the center of the rotor body; the size includes thickness and / or length.

4. The motor rotor according to claim 1, characterized in that: Each of the sub-magnets is square in shape.

5. The motor rotor according to claim 1, characterized in that: The coercive force of each sub-magnetic steel is greater than 500 kA / m.

6. The motor rotor according to claim 1, characterized in that: The included angle between the sub-magnetic steel of each magnetic steel unit and the radial bisector of the corresponding magnetic pole is between 30° and 70°.

7. The motor rotor according to claim 6, characterized in that: The magnetic steel units in the same magnetic steel group are not arranged in parallel, and the opening of the magnetic steel unit close to the center of the rotor body is smaller than the opening of the magnetic steel unit far from the center of the rotor body.

8. The motor rotor according to claim 6, characterized in that: The distance between the two sub-magnetic steels of the magnetic steel unit located in the inner layer is smaller than the distance between the two sub-magnetic steels of the magnetic steel unit located in the outer layer.

9. The motor rotor according to claim 1, characterized in that: Each of the magnetic steel units is symmetrical about the center of the rotor body, and the two sub-magnets of each magnetic steel unit are symmetrically arranged about the radial bisector of the magnetic pole.

10. A permanent magnet motor comprising the motor rotor according to any one of claims 1 to 9.

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