Asymmetric Rotor Structure and Its Permanent Magnet Motor

Abstract

The present application discloses an asymmetric rotor structure and a permanent magnet motor thereof. The asymmetric rotor structure includes a first iron core, a second iron core, a rotating shaft, and permanent magnets. The first iron core includes a plurality of preset regions, and a first mounting groove, a first magnetic barrier, and a second magnetic barrier are formed in the preset regions. The first magnetic barrier and the second magnetic barrier are respectively communicated with two ends of the first mounting groove. The second iron core and the first iron core are mirror-symmetric structures, and the number of the second iron cores is the same as that of the first iron cores. The permanent magnets are installed in a first mounting groove of each first iron core, and the permanent magnets penetrate through all the second iron cores and are fixed to the second iron cores. The first iron cores located on both sides of the symmetry plane are symmetrically arranged with respect to the symmetry plane, and the second iron cores located on both sides of the symmetry plane are symmetrically arranged with respect to the symmetry plane. The permanent magnet motor includes the above-mentioned asymmetric rotor structure. Through the above settings, the torque ripple, vibration noise, and axial unbalanced force generated by the permanent magnet motor can be reduced, and the operation reliability of the permanent magnet motor can be improved.

Description

Technical Field

[0001] This application relates to the technical field of motors, and in particular to an asymmetric rotor structure and its permanent magnet motor. Background Art

[0002] A permanent magnet motor is a motor that uses permanent magnets to generate an excitation magnetic field. It has many advantages such as high power density, high efficiency, and wide speed regulation range, and is widely used in many fields such as industrial servo, electrified transportation, and aerospace. As an important performance index, vibration and noise will significantly affect the operation reliability of a permanent magnet synchronous motor. Therefore, suppressing the vibration and noise of a permanent magnet synchronous motor is beneficial to further improve its operation efficiency and service life, and at the same time can effectively improve the stability, reliability, and performance level of the motor system.

[0003] Currently, in order to suppress the vibration and noise of a permanent magnet synchronous motor, common motor topologies include: skewed slot and skewed pole structures, asymmetric motor structures, etc. However, due to their own structural characteristics, existing various topologies have certain limitations. For example, in addition to significantly increasing the process complexity and the production cost of the motor, the skewed slot and skewed pole structures may also cause additional axial unbalanced magnetic pull force, which will exacerbate the damage of the motor bearings, shorten the service life, and further increase the vibration and noise of the motor; the asymmetric motor structure may destroy the symmetry and periodicity of the motor magnetic circuit, generate air-gap magnetic field harmonics and electromagnetic force harmonics of additional spatial orders, and even cause radial or axial unbalanced magnetic pull force, resulting in an increase in the vibration and noise of the motor.

[0004] Therefore, how to reduce the vibration and noise of a permanent magnet motor to improve the operation reliability of the permanent magnet motor is a technical problem that needs to be urgently solved by those skilled in the art. Summary of the Invention

[0005] In order to solve the deficiencies of the prior art, the purpose of this application is to provide an asymmetric rotor structure and its permanent magnet motor, which have lower vibration and noise and higher operation reliability.

[0006] To achieve the above purpose, this application adopts the following technical solutions:

[0007] An asymmetric rotor structure, which includes a first iron core, a second iron core, a rotating shaft, and permanent magnets. There are multiple first iron cores, multiple second iron cores, and multiple permanent magnets. Each first iron core is cylindrical, and each first iron core includes multiple preset regions arranged around the axis of the first iron core. Each preset region is provided with a first installation groove, a first magnetic barrier, and a second magnetic barrier. The first installation groove, the first magnetic barrier, and the second magnetic barrier all penetrate the first iron core along the axial direction of the first iron core. The first magnetic barrier and the second magnetic barrier are respectively connected to both ends of the first installation groove. The first installation groove extends along a preset straight line direction, the first magnetic barrier extends along a first straight line direction, and the second magnetic barrier extends along a second straight line direction. Define a projection plane perpendicular to the axial direction of the first iron core. The positive projection of the first straight line on the projection plane is a first projection line, the positive projection of the second straight line on the projection plane is a second projection line, and the positive projection of the preset straight line on the projection plane is a preset projection line. The included angle between the first projection line and the preset projection line is different from the included angle between the second projection line and the preset projection line. The second iron core and the first iron core are mirror-symmetric structures with the same number. Each permanent magnet is installed in a first installation groove of each first iron core, and each permanent magnet penetrates all the second iron cores and is fixed to the second iron cores. Define a symmetry plane perpendicular to the axial direction of the first iron core. The symmetry plane bisects the asymmetric rotor structure. At least one first iron core and at least one second iron core are arranged on both sides of the symmetry plane. The first iron cores on both sides of the symmetry plane are symmetrically arranged with respect to the symmetry plane, and the second iron cores on both sides of the symmetry plane are symmetrically arranged with respect to the symmetry plane.

[0008] Further, the second iron core is provided with multiple second installation grooves. Each second installation groove corresponds to a first installation groove. Each permanent magnet is installed in a first installation groove of each first iron core and a second installation groove corresponding to the first installation groove of each second iron core.

[0009] Further, the asymmetric rotor structure further includes magnetic isolation plates. There are multiple magnetic isolation plates, and the magnetic isolation plates are made of non-magnetic conductive materials. If a first iron core and a second iron core are arranged adjacent to each other, a magnetic isolation plate is arranged between the adjacent first iron core and second iron core, and the magnetic isolation plate is fixed to the adjacent first iron core and second iron core.

[0010] Further, each magnetic isolation plate is provided with multiple third installation grooves. Each third installation groove corresponds to a first installation groove. Each permanent magnet is installed in a first installation groove of each first iron core and a third installation groove corresponding to the first installation groove of each magnetic isolation plate. The rotating shaft penetrates through multiple first iron cores, multiple second iron cores, and multiple magnetic isolation plates and is fixed to multiple first iron cores, multiple second iron cores, and multiple magnetic isolation plates.

[0011] Further, the number of both the second iron cores and the first iron cores is a multiple of 2.

[0012] Further, the total length of all the first iron cores along the axial direction of the first iron cores is equal to the total length of all the second iron cores along the axial direction of the first iron cores.

[0013] Further, define the diameter of the first iron core perpendicular to the preset line as the bisecting diameter. The bisecting diameter bisects the first mounting groove, and the first magnetic barrier and the second magnetic barrier are located on both sides of the bisecting diameter. Define the end face of the first magnetic barrier away from the first mounting groove as the first end face, and the end face of the second magnetic barrier away from the first mounting groove as the second end face. The orthographic projection of the first end face on the projection plane is the first end face projection, and the orthographic projection of the second end face on the projection plane is the second end face projection. The orthographic projection of the axis of the first iron core on the projection plane is the axis projection point. The line connecting the midpoint of the first end face projection and the axis projection point is the first connection line, and the line connecting the midpoint of the second end face projection and the axis projection point is the second connection line. The orthographic projection of the bisecting diameter on the projection plane is the diameter projection line. The acute angle between the first connection line and the diameter projection line is the first included angle, and the acute angle between the second connection line and the diameter projection line is the second included angle. The angle of the first included angle is different from the angle of the second included angle. When the first included angle is greater than the second included angle, if the first connection line rotates around the axis projection point by a preset angle towards the diameter projection line, and the second connection line rotates around the axis projection point by a preset angle away from the diameter projection line, the diameter projection line bisects the included angle formed by the first connection line and the second connection line.

[0014] Further, the asymmetric rotor structure further includes fasteners and two end pressing plates made of non-magnetic materials. All the first iron cores and all the second iron cores are located between the two end pressing plates. The end pressing plates are provided with fixing holes, and the fasteners pass through the fixing holes and are fixedly connected to the first iron core or the second iron core adjacent to the end pressing plates. The rotating shaft passes through a plurality of first iron cores, a plurality of second iron cores, and two end pressing plates, and is fixed to the plurality of first iron cores, the plurality of second iron cores, and the two end pressing plates.

[0015] Further, a plurality of preset regions are uniformly arranged around the axis of the first iron core along the circumferential direction of the first iron core. The extending directions of the first mounting grooves in the plurality of preset regions are all perpendicular to the extending direction of a diameter of the first iron core, and the included angles between the two diameters corresponding to every two adjacent first mounting grooves are all the same.

[0016] To achieve the above object, the present application adopts the following technical solutions:

[0017] A permanent magnet motor, which includes the above-mentioned asymmetric rotor structure.

[0018] The above asymmetric rotor structure and its permanent magnet motor improve the electromagnetic force harmonics of the permanent magnet motor by asymmetrically arranging the first magnetic barrier and the second magnetic barrier and mirror-symmetrically arranging the first iron core and the second iron core, so that the torque pulsation and electromagnetic vibration generated by the first iron core cancel out the torque pulsation and electromagnetic vibration generated by the second iron core, thereby reducing the vibration noise generated during the operation of the permanent magnet motor; at the same time, by symmetrically arranging the first iron core along the symmetry plane and symmetrically arranging the second iron core along the symmetry plane, the axial unbalanced magnetic pulling force of the motor is eliminated, thereby improving the operation reliability of the permanent magnet motor. Description of the Drawings

[0019] Figure 1 It is a schematic structural diagram of the asymmetric rotor structure provided by the embodiment of the present application.

[0020] Figure 2 It is an exploded view of the asymmetric rotor structure provided by the embodiment of the present application.

[0021] Figure 3 It is a schematic structural diagram of the first iron core of the asymmetric rotor structure provided by the embodiment of the present application.

[0022] Figure 4 It is a time-domain waveform diagram of the cogging torque of the asymmetric rotor structure and the symmetric rotor structure provided by the embodiment of the present application.

[0023] Figure 5 It is a harmonic amplitude diagram of the cogging torque of the asymmetric rotor structure and the symmetric rotor structure provided by the embodiment of the present application.

[0024] Figure 6 It is a time-domain waveform diagram of the load torque of the asymmetric rotor structure and the symmetric rotor structure provided by the embodiment of the present application.

[0025] Figure 7 It is a harmonic amplitude diagram of the load torque of the asymmetric rotor structure and the symmetric rotor structure provided by the embodiment of the present application.

[0026] Figure 8 It is an electromagnetic vibration amplitude diagram of the asymmetric rotor structure and the symmetric rotor structure provided by the embodiment of the present application.

[0027] Figure 9 It is a schematic diagram of the preset angle of the first iron core of the asymmetric rotor structure provided by the embodiment of the present application.

[0028] Figure 10 It is a time-domain waveform diagram of the line back electromotive force of the asymmetric rotor structure and the symmetric rotor structure provided by the embodiment of the present application.

[0029] Figure 11 It is a harmonic amplitude diagram of the line back electromotive force of the asymmetric rotor structure and the symmetric rotor structure provided by the embodiment of the present application.

[0030] Figure 12 This is a schematic structural diagram of the second iron core of the asymmetric rotor structure provided by the embodiment of the present application.

[0031] Figure 13 This is a schematic structural diagram of the magnetic isolation plate of the asymmetric rotor structure provided by the embodiment of the present application. Detailed implementation manners

[0032] In order to enable those skilled in the art to better understand the solution of the present application, the technical solutions in the specific implementation manners of the present application will be clearly and completely described below in conjunction with the accompanying drawings in the implementation manners of the present application.

[0033] It should be noted that the "first", "second" and similar terms used in the specification and claims of the present application do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, terms such as "a" or "one" do not indicate a quantity limitation, but mean that there is at least one. "Multiple" or "several" means at least two. "Including" or "comprising" and similar terms mean that the elements or objects appearing before "including" or "comprising" cover the elements or objects listed after "including" or "comprising" and their equivalents, and do not exclude other elements or objects. "Connection" or "coupling" and similar terms are not limited to physical or mechanical connections, and may include electrical connections, whether direct or indirect.

[0034] The singular forms of "a", "the" and "said" used in the specification and appended claims of the present application are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0035] As Figure 1 and Figure 2 shown, the present application provides an asymmetric rotor structure 100, and this asymmetric rotor structure 100 can improve the electromagnetic force harmonics of a permanent magnet motor using this asymmetric rotor structure 100, and can suppress the torque ripple, electromagnetic vibration and axial unbalanced magnetic pull of the permanent magnet motor, thereby reducing the vibration noise generated during the operation of the permanent magnet motor and improving the operation reliability of the permanent magnet motor.

[0036] Specifically, the asymmetric rotor structure 100 includes a plurality of first iron cores 11, a plurality of second iron cores 12, a rotating shaft 13 and a plurality of permanent magnets 14.

[0037] Among them, the rotating shaft 13 passes through a plurality of first iron cores 11 and a plurality of second iron cores 12 and is fixed to the plurality of first iron cores 11 and the plurality of second iron cores 12, thereby forming the basic framework of the asymmetric rotor structure 100. It should be noted that the rotating shaft 13, the plurality of first iron cores 11, and the plurality of second iron cores 12 rotate synchronously. A plurality of permanent magnets 14 all pass through the plurality of first iron cores 11 and the plurality of second iron cores 12 and are fixed to the plurality of first iron cores 11 and the plurality of second iron cores 12. Among them, the permanent magnets 14 can be made of permanent magnetic materials (such as neodymium iron boron, samarium cobalt, ferrite, etc.) and are alternately arranged in the order of N poles and S poles along the circumferential direction of the rotating shaft 13.

[0038] Exemplarily, the rotating shaft 13 and the plurality of first iron cores 11 and the plurality of second iron cores 12 can be connected by interference fit; or, the rotating shaft 13 and the plurality of first iron cores 11 and the plurality of second iron cores 12 can be connected by keyways and keys, and the present application does not make any restrictions. Specifically, the plurality of first iron cores 11 and the plurality of second iron cores 12 are each provided with a shaft hole, and the rotating shaft 13 can pass through the shaft holes of the plurality of first iron cores 11 and the plurality of second iron cores 12.

[0039] Exemplarily, the first iron core 11 and the second iron core 12 are mirror-symmetric structures to each other, that is, the second iron core 12 can be considered to be formed by mirror symmetry of the first iron core 11, so the structures of the first iron core 11 and the second iron core 12 are the same. In the present application, the first iron core 11 and the second iron core 12 can be processed by the same set of stamping dies, and only need to rotate the first iron core 11 by 180° around a straight line where a certain diameter thereof is located to obtain the second iron core 12. Through the above settings, the processing efficiency of the first iron core 11 and the second iron core 12 can be improved, and the processing cost of the first iron core 11 and the second iron core 12 can be reduced.

[0040] It should be noted that the first iron core 11 and the second iron core 12 can be formed by laminating silicon steel sheets; or, the first iron core 11 and the second iron core 12 can be processed from soft magnetic composite materials; or, the first iron core 11 and the second iron core 12 can be processed from amorphous alloys, and the present application does not make any restrictions.

[0041] The present application takes the structure of the first iron core 11 as an example for description, and the structure of the second iron core 12 will not be elaborated further.

[0042] Such as Figure 2 and Figure 3As shown, as an implementation, each first iron core 11 is cylindrical. Each first iron core 11 includes a plurality of preset regions 111. The plurality of preset regions 111 are arranged around the axis of the first iron core 11. A first installation groove 112, a first magnetic barrier 113, and a second magnetic barrier 114 are formed on each preset region 111. The first installation groove 112, the first magnetic barrier 113, and the second magnetic barrier 114 all penetrate the first iron core 11 along the axial direction of the first iron core 11. The first magnetic barrier 113 and the second magnetic barrier 114 are respectively communicated with both ends of the first installation groove 112.

[0043] Among them, the first magnetic barrier 113 and the second magnetic barrier 114 are used to optimize the magnetic circuit design and improve the performance of the permanent magnet motor using the asymmetric rotor structure 100. By designing a multi-layer magnetic barrier structure, the reluctance torque can be fully utilized, thereby improving the torque density and power density of the permanent magnet motor using the asymmetric rotor structure 100.

[0044] Specifically, each permanent magnet 14 is installed in a first installation groove 112 of each first iron core 11, and each permanent magnet 14 penetrates through all the second iron cores 12 and is fixed to the second iron cores 12.

[0045] More specifically, the first installation groove 112 extends along the direction of the preset straight line 101, the first magnetic barrier 113 extends along the direction of the first straight line 102, and the second magnetic barrier 114 extends along the direction of the second straight line 103. Define a projection plane 104 perpendicular to the axial direction of the first iron core 11. The positive projection of the first straight line 102 on the projection plane 104 is the first projection line, the positive projection of the second straight line 103 on the projection plane 104 is the second projection line, and the positive projection of the preset straight line 101 on the projection plane 104 is the preset projection line. The included angle between the first projection line and the preset projection line is different from the included angle between the second projection line and the preset projection line. Through the above settings, the first magnetic barrier 113 and the second magnetic barrier 114 can be offset relative to each other to realize the asymmetric rotor structure 100 of the present application.

[0046] Such as Figures 4 to 9As shown, compared with the traditional symmetric rotor structure, in the asymmetric rotor structure 100 involved in the present application, the ends of the first magnetic barriers 113 and 114 of the first iron core 11 are respectively offset by a preset angle in the counterclockwise direction with the axis of the rotating shaft 13 as the center; the ends of the two magnetic barriers of the second iron core 12 are respectively offset by a preset angle in the clockwise direction with the axis of the rotating shaft 13 as the center, so as to effectively adjust the phase difference of the cogging torque, torque ripple and electromagnetic vibration generated by the first iron core 11 and the second iron core 12, so that the cogging torque, torque ripple and electromagnetic vibration generated by the first iron core 11 and the second iron core 12 cancel each other out, thereby reducing the overall cogging torque, torque ripple and electromagnetic vibration of the permanent magnet motor using the asymmetric rotor structure 100, and further improving the NVH (Noise, Vibration, Harshness) performance of the permanent magnet motor.

[0047] It should be noted that the ends of the first magnetic barrier 113 and the second magnetic barrier 114 refer to the ends of the first magnetic barrier 113 and the second magnetic barrier 114 far away from the first installation groove 112.

[0048] It should be noted that as Figure 9 shown, the principle and steps for selecting the preset angle are as follows:

[0049] In the asymmetric rotor structure 100 involved in the present invention, the first magnetic barrier 113 and the second magnetic barrier 114 have a modulation effect on the air-gap magnetic field. The expression of the air-gap magnetic field is related to the offset angles (i.e., the preset angles) of the first magnetic barrier 113 and the second magnetic barrier 114. Define the above offset angle as .

[0050] The air-gap magnetic fields generated by the first iron core 11 and the second iron core 12 can be respectively expressed as formulas (1) and (2):

[0051] (1)

[0052] (2)

[0053] Among them, is the radial air-gap magnetic field generated by the first iron core 11, is the tangential air-gap magnetic field generated by the first iron core 11, is the radial air-gap magnetic field generated by the second iron core 12, is the tangential air-gap magnetic field generated by the second iron core 12, is the harmonic amplitude of the radial air-gap magnetic field, is the harmonic amplitude of the tangential air-gap magnetic field, is the number of pole pairs of the permanent magnet motor, is the number of slots of the permanent magnet motor, is the rotational mechanical angular frequency of the permanent magnet motor, is the circumferential radius where the air-gap magnetic field is located, is the spatial position angle, is the time, is the identification variable of the rotation direction of the permanent magnet motor, is the harmonic order of the excitation magnetic field of the permanent magnet 14, is the harmonic order of the air-gap permeance produced by the stator slot opening of the permanent magnet motor, is the harmonic order of the air-gap permeance jointly produced by the first magnetic barrier 113 and the second magnetic barrier 114.

[0054] According to the Maxwell stress tensor method, the relationship between the electromagnetic force and the air-gap magnetic field in the permanent magnet motor can be expressed by Equation (3):

[0055] (3)

[0056] where, is the radial electromagnetic force, is the tangential electromagnetic force, is the radial air-gap magnetic field, is the tangential air-gap magnetic field, is the vacuum permeability.

[0057] Substituting Equation (1) and Equation (2) into Equation (3) respectively, the expressions of the radial and tangential electromagnetic forces generated by the first iron core 11 and the second iron core 12 can be derived, namely Equation (4) and Equation (5):

[0058] (4)

[0059] (5)

[0060] where, is the radial electromagnetic force generated by the first iron core 11, is the tangential electromagnetic force generated by the first iron core 11, is the radial electromagnetic force generated by the second iron core 12, is the tangential electromagnetic force generated by the second iron core 12, is the harmonic amplitude of the radial electromagnetic force, is the harmonic amplitude of the tangential electromagnetic force, is the harmonic order of the excitation magnetic field of the permanent magnet 14, is the harmonic order of the excitation magnetic field of the permanent magnet 14, is the harmonic order of the air-gap permeance produced by the stator slot opening of the permanent magnet motor, is the harmonic order of the air-gap permeance produced by the stator slot opening of the permanent magnet motor, is the harmonic order of the air-gap permeance jointly produced by the first magnetic barrier 113 and the second magnetic barrier 114, is the order of the air-gap permeance harmonic generated jointly by the first magnetic barrier 113 and the second magnetic barrier 114.

[0061] The tangential electromagnetic force is the excitation source of the motor torque, and the motor torque can be calculated by the loop integral along the circumferential direction of the air gap. Therefore, the cogging torque of the permanent magnet motor can be expressed as Equation (6):

[0062] (6)

[0063] where is the cogging torque of the permanent magnet motor, is the effective stack length of the permanent magnet motor, is the air-gap radius of the permanent magnet motor.

[0064] Substituting Equation (4) and Equation (5) into Equation (6) respectively, the expression of the cogging torque generated by the first iron core 11 and the second iron core 12 can be derived, that is, Equation (7):

[0065] (7)

[0066] where is the cogging torque generated by the first iron core 11, is the cogging torque generated by the second iron core 12, which can be further simplified to Equation (8):

[0067] (8)

[0068] where is the harmonic order of the cogging torque, is the number of poles of the permanent magnet motor and the number of slots is the least common multiple.

[0069] In order to weaken the torque harmonic component with the harmonic order of through the torque phase difference generated by the first iron core 11 and the second iron core 12, the offset angle of the first magnetic barrier 113 and the second magnetic barrier 114 needs to meet the conditions in Equation (9):

[0070] (9).

[0071] Therefore, the offset angle of the first magnetic barrier 113 and the second magnetic barrier 114 can be expressed as Equation (10):

[0072] (10).

[0073] Such as Figure 10 and Figure 11As shown above, through the above settings, the offset angles of the first magnetic barrier 113 and the second magnetic barrier 114 can be obtained. , so that the offset first magnetic barrier 113 and the second magnetic barrier 114 can have a phase offset effect on the air-gap magnetic field harmonics of the permanent magnet motor using the asymmetric rotor structure 100. The phase offset effect makes the line back electromotive force harmonics generated by the first iron core 11 and the second iron core 12 have inconsistent phases. Since the number of the second iron cores 12 in this application is the same as that of the first iron cores 11, the fifth and seventh time harmonics in the line back electromotive force of the permanent magnet motor can be significantly weakened, the sinusoidality of the line back electromotive force waveform of the permanent magnet motor can be improved, and then the line back electromotive force of the permanent magnet motor can be improved. At the same time, the phase offset effect makes the phases of the cogging torque and the torque ripple harmonics generated by the first iron core 11 and the second iron core 12 inconsistent. Since the number of the second iron cores 12 in this application is the same as that of the first iron cores 11, the cogging torque and the torque ripple of the permanent magnet motor can be significantly weakened, and there will be no difference in the torque performance of the permanent magnet motor during forward and reverse rotation.

[0074] In addition, due to the offset effect of the asymmetric rotor structure 100 on the air-gap magnetic field, the actual axis of the demagnetizing magnetic field generated by the d-axis demagnetizing current does not coincide with the d-axis axis of the permanent magnet 14. Therefore, the actual d-axis demagnetizing magnetic field borne by the permanent magnet 14 in the asymmetric rotor structure 100 is smaller and it is less likely to be demagnetized, so that the permanent magnet motor using the asymmetric rotor structure 100 has stronger demagnetization resistance.

[0075] In this embodiment, since the asymmetric rotor structure 100 may cause the inconsistency of the axial magnetic circuit of the permanent magnet motor, it may cause axial unbalanced magnetic pull force, which will further aggravate the bearing damage of the permanent magnet motor and shorten the working life.

[0076] To avoid the above problems, as Figure 2 and Figure 3 shown, a symmetry plane 105 perpendicular to the axial direction of the first iron core 11 is defined. The symmetry plane 105 bisects the asymmetric rotor structure 100. At least one first iron core 11 and at least one second iron core 12 are arranged on both sides of the symmetry plane 105. The first iron cores 11 on both sides of the symmetry plane 105 are symmetrically arranged with respect to the symmetry plane 105, and the second iron cores 12 on both sides of the symmetry plane 105 are symmetrically arranged with respect to the symmetry plane 105. Through the above settings, the number of the first iron cores 11 on both sides of the symmetry plane 105 can be made the same, and the number of the second iron cores 12 on both sides of the symmetry plane 105 can be made the same, thereby eliminating the axial unbalanced magnetic pull force.

[0077] In addition, in the present application, the modulation effects of the asymmetrically arranged first magnetic barrier 113 and second magnetic barrier 114 only change the phase of the electromagnetic force harmonics, do not change the specific spatio-temporal orders of the electromagnetic force harmonics, and do not introduce additional low-order spatial harmonics of the electromagnetic force. Therefore, it will not cause the problem of deterioration of the electromagnetic vibration of the low-order modes of the permanent magnet motor.

[0078] Meanwhile, through the asymmetrically arranged first magnetic barrier 113 and second magnetic barrier 114 and the mirror-symmetrically arranged first iron core 11 and second iron core 12, the electromagnetic vibrations generated by the first iron core 11 can be cancelled out by the electromagnetic vibrations generated by the second iron core 12, thereby reducing the vibration noise generated during the operation of the permanent magnet motor and improving the operation reliability and use comfort of the permanent magnet motor.

[0079] For the permanent magnet motor adopting the asymmetric rotor structure 100 involved in the present application, the electromagnetic force harmonics generated by the first iron core 11 and the second iron core 12 of the asymmetric rotor structure 100 have different phases. Therefore, the phases of the electromagnetic vibrations generated by the first iron core 11 and the second iron core 12 are also inconsistent. Thus, the electromagnetic vibrations generated by the first iron core 11 and the second iron core 12 can cancel each other out to a certain extent, effectively suppressing the overall electromagnetic vibration of the motor, thereby reducing the vibration noise generated during the operation of the permanent magnet motor and improving the operation reliability and use comfort of the permanent magnet motor.

[0080] It should be noted that for a traditional segmented skewed pole rotor, the skewed pole angle between its segments of iron cores needs to be controlled by a positioning tooling. On the one hand, the positioning tooling will increase the complexity and processing cost of the lamination process of the permanent magnet motor; on the other hand, the accuracy of the positioning tooling has a significant impact on the performance of the permanent magnet motor and will increase the inconsistency of the motor performance introduced by the lamination process. In particular, when the number of poles of the permanent magnet motor is large, the optimal skewed pole angle is generally small, and the segmented skewed pole rotor has higher requirements for the accuracy of the positioning tooling. For the asymmetric rotor structure 100 involved in the present application, the first iron core 11 and the second iron core 12 are mirror-symmetric, so its lamination process does not require an additional positioning tooling, which can effectively reduce the process complexity, save the processing cost, and improve the performance consistency of the permanent magnet motor.

[0081] It should be noted that when the stack length of the permanent magnet motor is kept constant, for the rotor of the traditional segmented skewed pole motor, the adjustment of the number of axial segments will cause corresponding adjustments to both the magnetic steel and the positioning tooling, resulting in additional processing production costs. For the asymmetric rotor structure 100 involved in the present application, the number of axial segments of the first iron core 11 and the second iron core 12 can be flexibly adjusted, that is, the number and stack length of the first iron core 11 and the second iron core 12 are adjustable, and the above problems will not occur. Among them, the stack length refers to the total length of the rotor iron core. For the asymmetric rotor structure 100 in the present application, the stack length refers to the total length of the first iron core 11 and the second iron core 12 along the axis of the first iron core 11.

[0082] It should be noted that in the traditional segmented skewed pole rotor, there are angular differences in the positions of the mounting grooves for the magnetic steel in each segment of the iron core. Therefore, the number of axial segments of the magnetic steel needs to be equal to the number of axial segments of the iron core, further increasing the complexity and processing costs of processes such as slicing finish machining, dimensional inspection, and electroplating in the magnetic steel production process. And when performing the magnetic steel assembly process, it is necessary to first insert the magnetic steel into the mounting groove and then perform the skewed pole operation through the positioning tooling. Therefore, the magnetism of the magnetic steel will bring great inconvenience to the skewed pole operation. In the asymmetric rotor structure 100 involved in the present application, the structures of the first iron core 11 and the second iron core 12 are the same. Therefore, the second iron core 12 also has a second mounting groove 121 that is the same as the first mounting groove 112, and the positions of the first mounting groove 112 and the second mounting groove 121 are exactly the same. Therefore, the magnetic steel 14 does not need to be additionally axially segmented, and the magnetic steel 14 can be directly inserted after the lamination process of the first iron core 11 and the second iron core 12 is completed. In addition, since the magnetic steel 14 has no additional axial segmentation, the number of assembly times is significantly reduced, which can effectively reduce the process complexity and save processing costs.

[0083] In addition, in the traditional segmented skewed pole rotor, the positions of the magnetic steel in each rotor segment are inconsistent, and the magnetic steel in a certain rotor segment will contact the iron core in the adjacent rotor segment, resulting in serious axial magnetic leakage at the radial magnetic rib part, thereby causing a decrease in the torque output ability of the permanent magnet motor. In the asymmetric rotor structure 100 involved in the present application, the positions of the magnetic steel 14 in the first iron core 11 and the second iron core 12 are exactly the same, and the magnetic steel 14 in the first iron core 11 and the second iron core 12 will not contact the adjacent first iron core 11 or second iron core 12. Therefore, the axial magnetic leakage at the radial magnetic rib part is significantly reduced. In addition, in the asymmetric rotor structure 100 involved in the present application, a magnetic isolation plate 15 made of non-magnetic material is installed between the first iron core 11 and the second iron core 12, further reducing the axial magnetic leakage, which is beneficial to the improvement of the motor torque output ability.

[0084] It should be noted that a relatively large centrifugal stress will be generated when the permanent magnet motor rotor rotates at a high speed. In a traditional rotor, the stress is mainly concentrated at the circumferential magnetic bridge position. However, the asymmetric rotor structure 100 involved in the present application can effectively increase the stress-bearing area, which helps to relieve the situation of excessive local stress. In addition, in the asymmetric rotor structure 100 involved in the present application, a stable triangular area is formed at the position of the radial magnetic ribs between two adjacent iron cores, which helps to improve stress and deformation, can improve the mechanical strength of the asymmetric rotor structure 100 to a certain extent, reduce the risk of structural and material failure, and increase the safety and reliability of the permanent magnet motor using the asymmetric rotor structure 100 under high-speed operating conditions.

[0085] As Figure 3 and Figure 12 shown, as an implementation manner, the second iron core 12 is provided with a plurality of second installation grooves 121, each second installation groove 121 corresponds to a first installation groove 112, and each magnet 14 is installed in a first installation groove 112 of each first iron core 11 and a second installation groove 121 corresponding to the first installation groove 112 of each second iron core 12. Through the above settings, the positions of the first installation groove 112 and the second installation groove 121 can be made completely consistent, so that the magnet 14 does not need to be axially segmented additionally, and the magnet 14 can be directly inserted after the lamination process of the first iron core 11 and the second iron core 12 is completed. In addition, since the magnet 14 has no additional axial segmentation, the number of assembly times is significantly reduced, which can effectively reduce the process complexity and save the processing cost. And, the magnet 14 in the first iron core 11 does not contact the adjacent second iron core 12, and the magnet in the second iron core 12 does not contact the adjacent first iron core 11, so the axial magnetic leakage at the radial magnetic rib part of the asymmetric rotor structure 100 is significantly reduced.

[0086] As Figure 2 , Figure 3 and Figure 13 shown, as an implementation manner, the asymmetric rotor structure 100 further includes a plurality of magnetic isolation plates 15 made of non-magnetic materials.

[0087] Exemplarily, if the first iron core 11 and the second iron core 12 are arranged adjacent to each other, a magnetic isolation plate 15 is arranged between the adjacent first iron core 11 and the second iron core 12, and the magnetic isolation plate 15 is fixed to the adjacent first iron core 11 and the second iron core 12, so as to further reduce the axial magnetic leakage between the first iron core 11 and the second iron core 12 and improve the torque output of the permanent magnet motor using the asymmetric rotor structure 100. And in order to improve the mechanical strength of the asymmetric rotor structure 100, the first iron core 11 and the magnetic isolation plate 15, and the second iron core 12 and the magnetic isolation plate 15 can be connected and fixed by gluing.

[0088] As an implementation, each magnetic shielding plate 15 is provided with a plurality of third mounting grooves 151. Each third mounting groove 151 corresponds to a first mounting groove 112. Each magnet 14 is mounted in a first mounting groove 112 of each first iron core 11 and a third mounting groove 151 of each magnetic shielding plate 15 corresponding to the first mounting groove 112. Wherein, the rotating shaft 13 passes through a plurality of first iron cores 11, a plurality of second iron cores 12 and a plurality of magnetic shielding plates 15 and is fixed to the plurality of first iron cores 11, the plurality of second iron cores 12 and the plurality of magnetic shielding plates 15. Through the above arrangement, the positions of the first mounting groove 112, the second mounting groove 121 and the third mounting groove 151 can be made completely consistent. Therefore, the magnet 14 does not need to be axially segmented additionally, and the magnet 14 can be directly inserted after the lamination process of the first iron core 11, the second iron core 12 and the magnetic shielding plate 15 is completed. In addition, since the magnet 14 has no additional axial segmentation, the number of assembly times is significantly reduced, the process complexity can be effectively reduced, and the processing cost can be saved. Moreover, the first iron core 11 does not contact the second iron core 12, so the axial magnetic leakage at the radial magnetic rib part is significantly reduced.

[0089] As an alternative implementation, the number of the second iron cores 12 and the first iron cores 11 are both multiples of 2. That is, the total number of the first iron cores 11 and the second iron cores 12 can be a multiple of 4.

[0090] Exemplarily, the number of the first iron cores 11 and the second iron cores 12 are both 2 for illustration. From one end to the other end of the rotating shaft 13 along its axial direction, the arrangement of 2 first iron cores 11 and 2 second iron cores 12 is: first iron core 11 - second iron core 12 - second iron core 12 - first iron core 11, or, second iron core 12 - first iron core 11 - first iron core 11 - second iron core 12.

[0091] Exemplarily, the number of the first iron cores 11 and the second iron cores 12 are both 4 for illustration. From one end to the other end of the rotating shaft 13 along its axial direction, the arrangement of 4 first iron cores 11 and 4 second iron cores 12 is: first iron core 11 - second iron core 12 - second iron core 12 - first iron core 11 - first iron core 11 - second iron core 12 - second iron core 12 - first iron core 11, or, second iron core 12 - first iron core 11 - first iron core 11 - second iron core 12 - second iron core 12 - first iron core 11 - first iron core 11 - second iron core 12, or, first iron core 11 - second iron core 12 - first iron core 11 - second iron core 12 - second iron core 12 - first iron core 11 - second iron core 12 - first iron core 11, or, second iron core 12 - first iron core 11 - second iron core 12 - first iron core 11 - first iron core 11 - second iron core 12 - first iron core 11 - second iron core 12.

[0092] Through the above settings, the first iron core 11 and the second iron core 12 set in mirror symmetry can make the torque ripple generated by the first iron core 11 cancel out the torque ripple generated by the second iron core 12, and the electromagnetic vibration generated by the first iron core 11 cancel out the electromagnetic vibration generated by the second iron core 12, thereby reducing the vibration and noise generated during the operation of the permanent magnet motor and improving the operation reliability and use comfort of the permanent magnet motor. At the same time, the electromagnetic force harmonics received by the first iron core 11 and the second iron core 12 have different phases, so the electromagnetic vibration phases generated by the first iron core 11 and the second iron core 12 are also inconsistent. Therefore, the electromagnetic vibrations generated by the first iron core 11 and the second iron core 12 can cancel each other out to a certain extent, effectively suppressing the overall electromagnetic vibration of the motor, thereby reducing the vibration and noise generated during the operation of the permanent magnet motor and improving the operation reliability and use comfort of the permanent magnet motor.

[0093] In this embodiment, the length of a single first iron core 11 along the axis of the first iron core 11 and the length of a single second iron core 12 along the axis of the first iron core 11 may not be the same, that is, it only needs to satisfy that the total length of all the first iron cores 11 along the axis of the first iron core 11 is equal to the total length of all the second iron cores 12 along the axis of the first iron core 11. Through the above settings, the lengths of the first iron core 11 and the second iron core 12 can be adjusted according to actual needs, so as to improve the diversity of the asymmetric rotor structure 100 to meet the structural and use requirements of different permanent magnet motors.

[0094] As Figure 3 and Figure 9 shown, as an implementation method, define the diameter of the first iron core 11 perpendicular to the preset straight line 101 as the bisecting diameter 106, the bisecting diameter 106 bisects the first installation groove 112, and the first magnetic barrier 113 and the second magnetic barrier 114 are located on both sides of the bisecting diameter 106. Define the end face of the first magnetic barrier 113 away from the first installation groove 112 as the first end face, the end face of the second magnetic barrier 114 away from the first installation groove 112 as the second end face, the orthographic projection of the first end face on the projection plane 104 as the first end face projection, the orthographic projection of the second end face on the projection plane 104 as the second end face projection, the orthographic projection of the axis of the first iron core 11 on the projection plane 104 as the axis projection point, the connection line between the midpoint of the first end face projection and the axis projection point as the first connection line, the connection line between the midpoint of the second end face projection and the axis projection point as the second connection line, the orthographic projection of the bisecting diameter 106 on the projection plane 104 as the diameter projection line, and the acute angle between the first connection line and the diameter projection line as the first included angle , and the acute angle between the second connection line and the diameter projection line as the second included angle , the first included angle is different from the angle of the second included angle .

[0095] It should be noted that when the first included angle is greater than the second included angle , if the first connecting line rotates around the projection point of the axis by a preset angle towards the diameter projection line, and the second connecting line rotates around the projection point of the axis by a preset angle away from the diameter projection line, the diameter projection line bisects the included angle formed by the first connecting line and the second connecting line. Among them, the calculation of the preset angle has been described above and will not be elaborated here.

[0096] Compared with the traditional symmetric rotor structure, in the asymmetric rotor structure 100 involved in the present application,

[0097] the ends of the first magnetic barrier 113 of the first iron core 11 (i.e., the end where the first end face is located) and the ends of the second magnetic barrier 114 of the first iron core 11 (i.e., the end where the second end face is located) are both centered on the axis of the rotating shaft 13 and are respectively offset by a preset angle in the counterclockwise direction; the ends of the two magnetic barriers of the second iron core 12 are both centered on the axis of the rotating shaft 13 and are respectively offset by a preset angle in the clockwise direction, so as to effectively adjust the phase difference of the cogging torque, torque ripple and electromagnetic vibration generated by the first iron core 11 and the second iron core 12, so that the cogging torque, torque ripple and electromagnetic vibration generated by the first iron core 11 and the second iron core 12 cancel each other out, thereby reducing the overall cogging torque, torque ripple and electromagnetic vibration of the permanent magnet motor using the asymmetric rotor structure 100, and further improving the NVH performance of the permanent magnet motor.

[0098] As shown in Figure 1 and Figure 2 , as an implementation manner, the asymmetric rotor structure 100 further includes a fastener 16 and two end pressing plates 17 made of non-magnetic conductive materials. All the first iron cores 11 and all the second iron cores 12 are located between the two end pressing plates 17. The end pressing plates 17 are provided with fixing holes 171. The fastener 16 passes through the fixing holes 171 and is fixedly connected to the first iron core 11 or the second iron core 12 adjacent to the end pressing plate 17. The rotating shaft 13 passes through a plurality of first iron cores 11, a plurality of second iron cores 12, a plurality of magnetic isolation plates 15 and the two end pressing plates 17, and is fixed to the plurality of first iron cores 11, a plurality of second iron cores 12, a plurality of magnetic isolation plates 15 and the two end pressing plates 17. Through the above settings, the end pressing plates 17 can axially limit the magnetic steel 14, the first iron core 11, the second iron core 12 and the magnetic isolation plates 15 to prevent the magnetic steel 14 from falling off from the first iron core 11, the second iron core 12 and the magnetic isolation plates 15; at the same time, the end pressing plates 17 can also be used as the weight removal part during the dynamic balance correction of the asymmetric rotor structure 100. For example, holes can be drilled in the end pressing plates 17 to achieve the dynamic balance of the asymmetric rotor structure 100.

[0099] As Figure 3 and Figure 9 shown, as an implementation, a plurality of preset regions 111 are uniformly arranged around the axis of the first iron core 11 along the circumferential direction of the first iron core 11. Specifically, the extending directions of the first mounting grooves 112 of the plurality of preset regions 111 are all perpendicular to the extending direction of a diameter of the first iron core 11, and the included angles between two diameters corresponding to every two adjacent first mounting grooves 112 are all the same. Through the above arrangement, the first mounting grooves 112, the first magnetic barriers 113, and the second magnetic barriers 114 on the first iron core 11 can be uniformly distributed on the first iron core 11, and the structures such as the second mounting grooves 121 on the second iron core 12 can be uniformly distributed on the second iron core 12, so that the asymmetric rotor structure 100 has rotational symmetry.

[0100] As an implementation, the present application also provides a permanent magnet motor, and the permanent magnet motor includes the above-mentioned asymmetric rotor structure 100.

[0101] It should be understood that for those of ordinary skill in the art, improvements or transformations can be made according to the above description, and all such improvements and transformations should fall within the protection scope of the appended claims of the present application.

Claims

1. An asymmetric rotor structure, characterized in that: The asymmetric rotor structure comprises: A plurality of first cores, each of which is cylindrical, and each of which includes a plurality of preset areas, which are arranged around the axis of the first core, and each of which is provided with a first mounting groove, a first magnetic barrier, and a second magnetic barrier, wherein the first mounting groove, the first magnetic barrier, and the second magnetic barrier are all arranged to penetrate the first core along the axis of the first core, and the first magnetic barrier and the second magnetic barrier are respectively connected to two ends of the first mounting groove, and the first mounting groove extends along a preset straight line direction, the first magnetic barrier extends along the first straight line direction, and the second magnetic barrier extends along the second straight line direction, defining a projection plane perpendicular to the axis of the first core, the orthographic projection of the first straight line on the projection plane is a first projection line, the orthographic projection of the second straight line on the projection plane is a second projection line, and the orthographic projection of the preset straight line on the projection plane is a preset projection line, and the angle between the first projection line and the preset projection line is different from the angle between the second projection line and the preset projection line; A plurality of second cores, wherein the second cores and the first cores are mirror-symmetrical structures, and the number of the second cores is the same as that of the first cores; a rotating shaft, the rotating shaft being passed through the plurality of the first iron cores and the plurality of the second iron cores and being fixed to the plurality of the first iron cores and the plurality of the second iron cores; A plurality of magnetic steels, each of which is installed in one of the first installation slots of each of the first iron cores, and each of which is passed through all of the second iron cores and fixed to the second iron cores; A symmetry plane perpendicular to the axial direction of the first iron core is defined, the symmetry plane bisects the asymmetric rotor structure, at least one first iron core and at least one second iron core are disposed on both sides of the symmetry plane, the first iron cores located on both sides of the symmetry plane are symmetrically disposed with respect to the symmetry plane, and the second iron cores located on both sides of the symmetry plane are symmetrically disposed with respect to the symmetry plane; The ends of the first magnetic barrier and the second magnetic barrier are both centered on the axis of the rotating shaft and are offset by a preset angle in the counterclockwise direction. , the preset angle Satisfies the following formula: ;in, is the harmonic order of the cogging torque, is the least common multiple of the number of poles and the number of slots of the permanent magnet motor using the asymmetric rotor structure.

2. The asymmetric rotor structure according to claim 1, characterized in that: The second iron core is provided with a plurality of second mounting grooves, each of the second mounting grooves corresponds to one of the first mounting grooves, and each of the magnetic steels is installed in one of the first mounting grooves of each of the first iron cores and one of the second mounting grooves of each of the second iron cores corresponding to the first mounting grooves.

3. The asymmetric rotor structure according to claim 1 or 2, characterized in that: The asymmetric rotor structure further comprises a plurality of magnetic isolation plates made of non-magnetic conductive materials; If the first iron core and the second iron core are arranged adjacent to each other, a magnetic isolation plate is arranged between the adjacent first iron core and the second iron core, and the magnetic isolation plate is fixed to the adjacent first iron core and the second iron core.

4. The asymmetric rotor structure according to claim 3, characterized in that: Each of the magnetic isolation plates is provided with a plurality of third mounting grooves, each of the third mounting grooves corresponds to one of the first mounting grooves, and each of the magnetic steels is mounted on one of the first mounting grooves of each of the first iron cores and one of the third mounting grooves of each magnetic isolation plate corresponding to the first mounting groove; The rotating shaft passes through the plurality of first iron cores, the plurality of second iron cores and the plurality of magnetic isolation plates, and is fixed to the plurality of first iron cores, the plurality of second iron cores and the plurality of magnetic isolation plates.

5. The asymmetric rotor structure according to claim 1, characterized in that: The number of the second iron cores and the number of the first iron cores are both multiples of 2.

6. The asymmetric rotor structure according to claim 1, characterized in that: The total length of all the first cores along the axial direction of the first core is equal to the total length of all the second cores along the axial direction of the first core.

7. The asymmetric rotor structure according to claim 1, characterized in that: Define the diameter of the first iron core perpendicular to the preset straight line as the bisecting diameter, the bisecting diameter bisects the first mounting slot, and the first magnetic barrier and the second magnetic barrier are located on both sides of the bisecting diameter; define the end face of the first magnetic barrier away from the first mounting slot as the first end face, the end face of the second magnetic barrier away from the first mounting slot as the second end face, the orthographic projection of the first end face on the projection plane as the first end face projection, the orthographic projection of the second end face on the projection plane as the second end face projection, the orthographic projection of the axis of the first iron core on the projection plane as the axis projection point, the line connecting the midpoint of the first end face projection and the axis projection point as the first connecting line, the line connecting the midpoint of the second end face projection and the axis projection point as the second connecting line, the orthographic projection of the bisecting diameter on the projection plane as the diameter projection line, the acute angle between the first connecting line and the diameter projection line as the first angle, the acute angle between the second connecting line and the diameter projection line as the second angle, and the angle of the first angle is different from the angle of the second angle; When the first angle is greater than the second angle, if the first connecting line rotates around the axis projection point by a preset angle toward the diameter projection line, and the second connecting line rotates around the axis projection point by the preset angle away from the diameter projection line, the diameter projection line bisects the angle formed by the first connecting line and the second connecting line.

8. The asymmetric rotor structure according to claim 1, characterized in that: The asymmetric rotor structure further includes a fastener and two end pressure plates made of non-magnetic conductive material, all the first iron cores and all the second iron cores are located between the two end pressure plates, the end pressure plates are provided with fixing holes, the fasteners are passed through the fixing holes and fixedly connected to the first iron core or the second iron core adjacent to the end pressure plates; The rotating shaft passes through the plurality of first iron cores, the plurality of second iron cores and the two end pressure plates, and is fixed to the plurality of first iron cores, the plurality of second iron cores and the two end pressure plates.

9. The asymmetric rotor structure according to claim 1, characterized in that: The plurality of preset areas are uniformly arranged around the axis of the first core along the circumference of the first core; The extension directions of the first installation slots in the plurality of preset areas are all perpendicular to the extension direction of a diameter of the first core, and the angles between the two diameters corresponding to every two adjacent first installation slots are all consistent.

10. A permanent magnet motor, characterized in that: The permanent magnet motor comprises the asymmetric rotor structure according to any one of claims 1 to 9.

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