Spoke-type rotor structure and permanent magnet motor

Abstract

The present application provides a spoke-type rotor structure and a permanent magnet motor, wherein the spoke-type rotor structure includes an integrated rotor punching and a plurality of split rotor punchings. The integrated rotor punching includes a center hole and a plurality of rotor sectors, each of which is arranged in sequence along the circumferential direction of the center hole; the split rotor punchings are arranged at intervals from each other along the circumferential direction of the center hole, and the barrier effect of the split rotor punchings is utilized to change the magnetic field path generated by the end of the permanent magnet, thereby suppressing the leakage of the magnetic field at the end of the permanent magnet. Each split rotor punching corresponds to each rotor sector. When constructing the rotor core, the integrated rotor punchings and the split rotor punchings are alternately stacked along the axial direction of the rotor and accumulated layer by layer. The outer edges of the integrated rotor punchings and the split rotor punchings are both provided with grooves extending in the thickness direction, which can not only weaken the local magnetic field distortion caused by the split rotor punchings, but also promote the uniform transmission of magnetic force, thereby reducing the amplitude of torque pulsation.

Description

Technical Field

[0001] The present application belongs to the technical field of permanent magnet motors, and more specifically, relates to a spoke-type rotor structure and a permanent magnet motor. Background Art

[0002] With the continuous development of motor technology, permanent magnet motors have been widely used in many industrial fields due to their high efficiency, high power density and excellent torque output characteristics. In particular, the spoke-type internal permanent magnet motor, with its unique structural design and optimized magnetic circuit layout, has shown significant performance advantages in wind power generation, electric vehicle drive systems, industrial transmission equipment and other fields. This type of motor maximizes the use of the magnetic field by embedding permanent magnets inside the rotor, thereby effectively improving the output torque and overall efficiency of the motor.

[0003] However, despite the excellent performance of the spoke-type internal permanent magnet motor, the leakage problem at the ends of the magnets has become a key factor restricting its further development. This is mainly due to the arrangement of the permanent magnets and the rotor structure. Specifically, the permanent magnets are designed to be embedded in the rotor in a spoke shape. Although this can enhance the utilization of the magnetic flux path, it also makes the magnetic field distribution at both ends of the magnet uneven. Due to the asymmetry of the magnetic circuit, the magnetic field intensity at the ends of the magnets is often higher than that in other areas, resulting in leakage. The leakage problem will not only cause interference with the external magnetic field of the motor and affect the normal operation of peripheral equipment, but also reduce the overall efficiency of the motor and increase energy consumption. In addition, leakage may also cause an imbalance in the electromagnetic force inside the motor, accelerate the wear of motor components, and shorten the service life of the motor. Summary of the invention

[0004] The purpose of the embodiments of the present application is to provide a spoke-type rotor structure and a permanent magnet motor to solve the technical problem of serious magnetic leakage at both ends of the permanent magnet in the spoke-type internal permanent magnet motor in the prior art.

[0005] To achieve the above purpose, the technical solution adopted in this application is:

[0006] A spoke-type rotor structure is provided, comprising:

[0007] An integrated rotor punching sheet comprises a central hole and a plurality of rotor sectors, wherein the rotor sectors are arranged in sequence along the circumferential direction of the central hole;

[0008] A plurality of split rotor punchings, each of the split rotor punchings is arranged at intervals from each other along the circumferential direction of the center hole and corresponds one-to-one to each of the rotor sectors;

[0009] The integrated rotor punching sheets and the split rotor punching sheets are alternately stacked on each other along the axial direction of the rotor;

[0010] The outer edges of the integrated rotor punching sheet and the split rotor punching sheet are both provided with grooves extending in the thickness direction.

[0011] As a further improvement of the above technical solution:

[0012] Optionally, there are multiple grooves, and the grooves are arranged on the outer circumferential surface of the integrated rotor punching sheet at intervals from each other, or are arranged on the outer arc edge of the split rotor punching sheet.

[0013] Optionally, the bottom of the groove is an arc-shaped surface, and the arc-shaped surface is recessed toward the inner side of the integrated rotor punching sheet or the split rotor punching sheet.

[0014] Optionally, the Carter coefficient of the spoke-type rotor structure is:

[0015]

[0016] Among them, τ s = , is the diameter of the rotor, g is the uniform air gap length of the motor without grooves, and h is s is the depth of the groove, b1 is the width of the groove, and b2 is half of the distance between the two grooves.

[0017] Optionally, at least two layers of the split rotor punchings are stacked between two adjacent one-piece rotor punchings.

[0018] Optionally, each of the rotor sectors and each of the split rotor punchings is provided with a magnetic isolation hole.

[0019] Optionally, a permanent magnet mounting groove is further provided on the one-piece rotor punching sheet, and the permanent magnet mounting groove is located between each of the rotor sectors, and the permanent magnet mounting groove corresponds to the interval between each of the split rotor punching sheets.

[0020] Optionally, a rivet is also included; the one-piece rotor punch is provided with a first rivet hole, the split rotor punch is provided with a second rivet hole, and the rivet passes through the first rivet hole and the second rivet hole to rivet the one-piece rotor punch and the split rotor punch into a whole.

[0021] The present application also provides a permanent magnet motor, comprising the above-mentioned spoke-type rotor structure.

[0022] The spoke-type rotor structure and permanent magnet motor provided by the present application have the following beneficial effects:

[0023] The spoke-type rotor structure provided by the present application includes an integrated rotor punching and a plurality of split rotor punchings. Among them, the integrated rotor punching includes a center hole and a plurality of rotor sectors. The center hole is used to install the rotor shaft. Each rotor sector is arranged in sequence along the circumferential direction of the center hole. In order to solve the problem of magnetic leakage at the end of the permanent magnet in a targeted manner, the present invention creatively introduces a plurality of split rotor punchings. These split rotor punchings are arranged at intervals from each other along the circumferential direction of the center hole, and the physical barrier effect of the split rotor punchings is used to change the magnetic field path generated by the end of the permanent magnet, thereby suppressing the leakage of the magnetic field at the end of the permanent magnet, reducing the magnetic leakage loss, and improving the magnetic energy conversion efficiency of the motor. Each split rotor punching corresponds to each rotor sector one by one, ensuring the stability and consistency of the spoke-type rotor structure of the present application during the rotation process. When constructing the rotor core, the integrated rotor punchings and the split rotor punchings are alternately stacked along the axial direction of the rotor, and accumulated layer by layer until the required rotor thickness and mechanical strength are reached. The outer edges of the integrated rotor laminations and the split rotor laminations are provided with grooves extending in the thickness direction to solve the problem of increased torque pulsation caused by the split rotor laminations, thereby ensuring the smooth operation of the motor. By changing the geometric shape of the rotor lamination edge, the magnetic field distribution and magnetic flux path generated by the rotor during rotation are effectively adjusted. On the one hand, the local magnetic field distortion caused by the split rotor laminations can be weakened, and on the other hand, the uniform transmission of magnetic force is promoted, thereby reducing the amplitude of torque pulsation.

[0024] The permanent magnet motor of the present application includes the above-mentioned spoke-type rotor structure, and therefore also has the advantages of the above-mentioned spoke-type rotor structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 A schematic diagram of the main structure of the integrated rotor punching of the spoke-type rotor structure provided in the present application;

[0027] Figure 2 A schematic diagram of the main structure of a split rotor punching of a spoke-type rotor structure provided in the present application;

[0028] Figure 3 A partially enlarged structural schematic diagram of a split rotor punching sheet of a spoke-type rotor structure provided in the present application;

[0029] Figure 4 A schematic diagram of the parameter positions of the spoke-type rotor structure provided in this application;

[0030] Figure 5 A schematic diagram of the magnetic circuit distribution of the integrated rotor punching sheet of the spoke-type rotor structure provided in the present application;

[0031] Figure 6 A schematic diagram of the magnetic circuit distribution of the split rotor punchings of the spoke-type rotor structure provided in this application.

[0032] Among them, the reference numerals in the figure are:

[0033] 1. One-piece rotor punching; 11. Center hole;

[0034] 12. rotor sector; 13. first riveting hole;

[0035] 2. Split rotor punching; 21. Second riveting hole;

[0036] 3. Groove; 4. Magnetic isolation hole;

[0037] 5. Permanent magnet mounting slot. DETAILED DESCRIPTION

[0038] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0039] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0040] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0041] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0042] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0043] In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of the present invention.

[0044] In the following description, suffixes such as "module", "component", "assembly" or "unit" are used only to facilitate the description of the present invention and have no specific meanings. Therefore, they can be used in combination.

[0045] The present invention will be further described in detail below through specific implementation modes in conjunction with the accompanying drawings.

[0046] like Figures 1 to 3 As shown, the present application provides a spoke-type rotor structure, including an integrated rotor punching 1 and a plurality of split rotor punchings 2. Among them, the integrated rotor punching 1 includes a center hole 11 and a plurality of rotor sectors 12. The center hole 11 is used to install the rotor shaft. The rotor sectors 12 are arranged in sequence along the circumferential direction of the center hole 11. In order to specifically solve the problem of magnetic leakage at the end of the permanent magnet, the present invention creatively introduces a plurality of split rotor punchings 2. These split rotor punchings 2 are arranged at intervals from each other along the circumferential direction of the center hole 11, and the physical barrier effect of the split rotor punchings 2 is utilized to change the magnetic field path generated at the end of the permanent magnet, thereby suppressing the leakage of the magnetic field at the end of the permanent magnet, reducing magnetic leakage losses, and improving the magnetic energy conversion efficiency of the motor. As shown Figure 5As shown in FIG. 1 , the magnetic circuit distribution at both ends of the permanent magnet on the integrated rotor punching 1 is shown. The two ends of the permanent magnet easily form a loop in the rotor punching (iron core), thereby generating magnetic leakage. Figure 6 As shown, the magnetic circuit distribution at both ends of the permanent magnet on the split rotor punching 2 is shown. The permanent magnet is placed between two adjacent split rotor punchings 2. Since there is no iron core at both ends of the permanent magnet, the occurrence of magnetic leakage can be effectively reduced.

[0047] Each split rotor punching 2 corresponds to each rotor sector 12 one by one, ensuring the stability and consistency of the spoke-type rotor structure of the present application during rotation. When constructing the rotor core, the integrated rotor punching 1 and the split rotor punching 2 are alternately stacked along the axis of the rotor, accumulating layer by layer until the required rotor thickness and mechanical strength are achieved.

[0048] The outer edges of the integrated rotor laminations 1 and the split rotor laminations 2 are both provided with grooves 3 extending in the thickness direction to solve the problem of increased torque pulsation caused by the split rotor laminations 2, thereby ensuring the smooth operation of the motor. By changing the geometric shape of the rotor lamination edge, the magnetic field distribution and magnetic flux path generated by the rotor during rotation are effectively adjusted, which can weaken the local magnetic field distortion caused by the split rotor laminations 2 on the one hand, and promote the uniform transmission of magnetic force on the other hand, thereby reducing the amplitude of torque pulsation.

[0049] like Figures 1 to 3 As shown, in one embodiment of the present application, there are multiple grooves 3, and each groove 3 is arranged at intervals on the outer circumferential surface of the integral rotor punching 1, or arranged on the outer arc edge of the split rotor punching 2. Under the joint action of each groove 3, the torque pulsation is suppressed together.

[0050] like Figures 1 to 3 As shown, in one embodiment of the present application, the bottom of the groove 3 is an arc-shaped surface, and the arc-shaped surface is recessed toward the inner side of the integral rotor punching sheet 1 or the split rotor punching sheet 2 .

[0051] According to motor-related theory, the torque pulsation generated by the sinusoidally excited synchronous motor through the fifth and seventh spatial harmonics of the air gap flux density interacting with the fifth and seventh harmonics of the stator current density distribution is:

[0052] (1)

[0053] in, is the torque ripple, is the inner diameter of the stator, is the effective length of the stator, is the harmonic component of the air gap magnetic density, is the harmonic component of the stator surface current density, and h represents the fifth or seventh harmonic component.

[0054] Once the motor design is completed, , , It is also basically determined that the torque pulsation is related to the 5th and 7th harmonic components of the air gap flux density.

[0055] And because the air gap flux density of the motor can be expressed as:

[0056] (2)

[0057] in, is the magnetic permeability, F is the air gap magnetomotive force, is the effective length of the air gap.

[0058] In the present application, the air gap length of the motor is changed by means of the groove 3, so it is necessary to introduce the Carter coefficient to analyze the change of the air gap magnetic flux density.

[0059] like Figure 4 As shown, γ is the center position of groove 3, θ is the width of groove 3, and h s is the depth of groove 3, D or is the outer diameter of the rotor. For the convenience of calculation, γ and θ are converted into actual lengths as shown in formula (3):

[0060] (3)

[0061] After deduction, the Carter coefficient of the rotor surface with groove 3 is:

[0062] (4)

[0063] Among them, h s is the depth of groove 3.

[0064] The actual equivalent air gap length of the motor is:

[0065] (5)

[0066] Among them, g is the uniform air gap length of the motor when the rotor does not have groove 3, b1 is the width of the groove, and b2 is half of the distance between the two grooves.

[0067] Based on the above formula, it can be seen that the opening of the groove 3 on the surface of the motor rotor can change the air gap length of the motor, thereby adjusting the 5th and 7th harmonic components of the air gap magnetic flux density of the motor, thereby achieving the purpose of reducing torque pulsation. Since the functional relationship between the Carter coefficient and the three variables is too complicated, the optimal solution for reducing torque pulsation can be obtained by finding the three variables through optimization.

[0068] In one embodiment of the present application, at least two layers of split rotor sheets 2 are stacked between two adjacent integral rotor sheets 1. The more layers of split rotor sheets 2 stacked between two adjacent integral rotor sheets 1, the better the effect of suppressing magnetic leakage at the ends of the permanent magnets, but the lower the structural strength of the rotor core; conversely, the fewer layers of split rotor sheets 2 stacked between two adjacent integral rotor sheets 1, the higher the structural strength of the rotor core, but the worse the effect of suppressing magnetic leakage at the ends of the permanent magnets. In practical applications, the number of layers of split rotor sheets 2 stacked between two adjacent integral rotor sheets 1 can be adjusted according to specific needs to achieve the best performance index.

[0069] like Figures 1 to 3 As shown, in one embodiment of the present application, each rotor sector 12 and each split rotor punching sheet 2 is provided with a magnetic isolation hole 4. The introduction of the magnetic isolation hole 4 not only makes the magnetic lines of force on both sides thereof denser, thereby effectively enhancing the output torque of the motor. In addition, the magnetic isolation hole 4 can also reduce the overall weight of the motor to improve the motor performance such as the torque density and power density of the motor. In order to ensure that the magnetic isolation hole 4 can play the best performance, the specific position and size of the magnetic isolation hole 4 are optimized by analyzing the magnetic density cloud map and magnetic lines of force of the motor.

[0070] like Figure 1 As shown, in one embodiment of the present application, a permanent magnet mounting groove 5 is further provided on the integral rotor punching 1, and the permanent magnet mounting groove 5 is located between each rotor sector 12, and the permanent magnet mounting groove 5 corresponds to the interval between each split rotor punching 2. The permanent magnet is installed in the permanent magnet mounting groove 5, thereby forming a built-in permanent magnet rotor.

[0071] like Figures 1 to 3 As shown, in one embodiment of the present application, the spoke-type rotor structure further includes a rivet. A first rivet hole 13 is provided on the integrated rotor punching 1, and a second rivet hole 21 is provided on the split rotor punching 2, and the position of the second rivet hole 21 corresponds to the position of the first rivet hole 13. The rivet runs through the first rivet hole 13 and the second rivet hole 21 to rivet the integrated rotor punching 1 and the split rotor punching 2 into a whole, which not only simplifies the assembly process of the traditional rotor structure and reduces the manufacturing cost, but also improves the overall rigidity and anti-deformation ability of the rotor core, effectively avoids loosening or breakage caused by vibration or high-speed rotation, and ensures the stability and safety of the rotor core under long-term and high-load operation.

[0072] The present application provides a permanent magnet motor, including the spoke-type rotor structure in the above embodiment, and also including permanent magnets, a stator, a housing, etc. Since the permanent magnet motor has the spoke-type rotor structure in the above embodiment, it also has the advantages of the spoke-type rotor structure in the above embodiment.

[0073] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A spoke-type rotor structure, characterized in that: include: An integrated rotor punching sheet (1) comprises a central hole (11) and a plurality of rotor sectors (12), wherein the rotor sectors (12) are arranged in sequence along the circumferential direction of the central hole (11); a plurality of split rotor punchings (2), each of the split rotor punchings (2) being arranged at intervals from one another along the circumferential direction of the central hole (11) and corresponding one-to-one to each of the rotor sectors (12); The integrated rotor punching sheets (1) and the split rotor punching sheets (2) are alternately stacked on each other along the axial direction of the rotor; The outer edges of the integrated rotor punching sheet (1) and the split rotor punching sheet (2) are both provided with grooves (3) extending in the thickness direction; The Carter coefficient of the spoke-type rotor structure is: Among them, τ s = , is the diameter of the rotor, g is the uniform air gap length of the motor without grooves (3), h s is the depth of the groove (3), b1 is the width of the groove (3), and b2 is half the distance between the two grooves (3); Through the Carter coefficient calculation formula, h is obtained s The optimal solution of b1, b2 is used to adjust the 5th and 7th harmonic components of the motor air gap flux density, thereby reducing the torque pulsation.

2. The spoke-type rotor structure according to claim 1, characterized in that: The number of the grooves (3) is plural, and the grooves (3) are arranged at intervals from each other on the outer circumferential surface of the integral rotor punching sheet (1), or on the outer arc edge of the split rotor punching sheet (2).

3. The spoke-type rotor structure according to claim 1, characterized in that: The groove bottom of the groove (3) is an arc-shaped surface, and the arc-shaped surface is recessed toward the inner side of the integrated rotor punching sheet (1) or the split rotor punching sheet (2).

4. The spoke-type rotor structure according to any one of claims 1 to 3, characterized in that: At least two layers of the split rotor punching sheets (2) are stacked between two adjacent one-piece rotor punching sheets (1).

5. The spoke-type rotor structure according to any one of claims 1 to 3, characterized in that: Each of the rotor sectors (12) and each of the split rotor punching sheets (2) is provided with a magnetic isolation hole (4).

6. The spoke-type rotor structure according to any one of claims 1 to 3, characterized in that: The one-piece rotor punching sheet (1) is also provided with a permanent magnet mounting groove (5), the permanent magnet mounting groove (5) is located between each of the rotor sectors (12), and the permanent magnet mounting groove (5) corresponds to the interval between each of the split rotor punching sheets (2).

7. The spoke-type rotor structure according to any one of claims 1 to 3, characterized in that: It also includes a riveting piece; the integrated rotor punching sheet (1) is provided with a first riveting hole (13), the split rotor punching sheet (2) is provided with a second riveting hole (21), and the riveting piece passes through the first riveting hole (13) and the second riveting hole (21) so as to rivet the integrated rotor punching sheet (1) and the split rotor punching sheet (2) into a whole.

8. A permanent magnet motor, characterized in that: It comprises the spoke-type rotor structure as claimed in any one of claims 1 to 7.

Images