Permanent magnet servo motor

Abstract

This application provides a permanent magnet servo motor, which includes a stator, an armature winding, multiple permanent magnets, a rotor, and a shaft. The rotor surrounds the outside of the shaft, and the stator surrounds the outside of the rotor and is spaced apart from it. The multiple permanent magnets are disposed on the rotor and located between the rotor and the stator, and the armature winding is disposed on the stator. The stator teeth include multiple wide teeth and multiple narrow teeth, each group consisting of pairs of wide and narrow teeth, which are equidistantly alternating along the circumference of the stator. By grouping the wide and narrow teeth in pairs and equidistantly alternating them along the circumference of the stator, the magnetic field distribution of the permanent magnet servo motor can be optimized, effectively reducing low-order harmonics, thereby effectively suppressing cogging torque, reducing torque pulsation, and improving the smoothness of the permanent magnet servo motor's operation.

Description

Technical Field

[0001] This application relates to the field of motor technology, specifically to a permanent magnet servo motor. Background Technology

[0002] Permanent magnet servo motors (PMSMs) have significant advantages in core performance such as precision, efficiency, and dynamic response due to their unique structural design. They are widely applicable to scenarios with high control requirements, such as automated equipment and precision manufacturing, and therefore have broad application prospects in fields such as industrial automation, new energy vehicles, rail transportation, aerospace, and medical equipment.

[0003] In existing permanent magnet servo motors, the magnetic permeation harmonics are spatially dispersed, and the harmonic components exhibit a complex superposition state in the magnetic field, making it difficult to cancel low-order harmonics. Consequently, a large number of low-order harmonic components remain in the cogging torque. These residual low-order harmonic components cause motor torque pulsation and affect the smoothness of permanent magnet servo motor operation. Summary of the Invention

[0004] In view of the above problems, this application provides a permanent magnet servo motor that can reduce torque ripple and improve the smoothness of permanent magnet servo motor operation.

[0005] To solve the above-mentioned technical problems, the technical solution adopted in this application is conceived as follows: This application provides a permanent magnet servo motor, including a stator, an armature winding, multiple permanent magnets, a rotor, and a shaft. The rotor surrounds the outside of the shaft, and the stator surrounds the outside of the rotor and is spaced apart from the rotor. Multiple permanent magnets are disposed on the rotor and located between the rotor and the stator, and the armature winding is disposed on the stator. The stator teeth of the stator include multiple wide teeth and multiple narrow teeth. The multiple wide teeth and multiple narrow teeth are each grouped in pairs, and the multiple wide tooth groups and multiple narrow tooth groups are equidistantly distributed and alternately distributed along the circumference of the stator.

[0006] The rotor is equipped with multiple auxiliary slots, and each of the auxiliary slots corresponds to a permanent magnet.

[0007] The auxiliary slot's central axis along the rotor's circumference coincides with the central axis of the corresponding permanent magnet along the rotor's circumference.

[0008] Among them, the maximum dimension of the auxiliary slot along the rotor circumference is less than or equal to the dimension of the permanent magnet along the rotor circumference.

[0009] The slot opening of the auxiliary slot is located on the outer surface of the rotor, and the circumferential dimension of the slot opening along the rotor is less than or equal to 50% of the distance between two adjacent permanent magnets.

[0010] Each auxiliary slot includes multiple interconnected sub-auxiliary slots; in the radial direction of the rotor, the dimensions of the multiple sub-auxiliary slots decrease in a stepped manner from the inside to the outside; and / or, the dimensions of the multiple sub-auxiliary slots decrease in a stepped manner from the inside to the outside along the circumferential direction of the rotor.

[0011] The difference between the radial dimensions of two adjacent sub-auxiliary slots along the rotor is 0.3mm to 0.8mm.

[0012] Each auxiliary slot has 2 to 3 sub-auxiliary slots.

[0013] The inner wall of the auxiliary groove is arc-shaped.

[0014] The cross-sections of both the wide and narrow teeth are trapezoidal, and in the radial direction of the stator, the dimensions of both the wide and narrow teeth gradually increase from the inside to the outside along the circumference of the stator.

[0015] Among them, at the same radial dimension of the stator, the ratio between the circumferential dimension of the wide tooth and the circumferential dimension of the narrow tooth is 1.1 to 1.6.

[0016] The ratio of the circumferential dimension of the wide tooth near the rotor along the stator to the circumferential dimension of the wide tooth away from the rotor along the stator is 0.6 to 0.8; the ratio of the circumferential dimension of the narrow tooth near the rotor along the stator to the circumferential dimension of the narrow tooth away from the rotor along the stator is 0.6 to 0.8.

[0017] Among them, a receiving slot is formed between two adjacent stator teeth, which is used to accommodate the armature winding; in the radial direction of the stator, the size of the receiving slot gradually increases from the inside to the outside along the circumferential direction of the stator.

[0018] In this arrangement, the magnetism of multiple permanent magnets is alternately arranged along the circumference of the rotor, and each permanent magnet has the same circumferential dimension and the same radial dimension along the rotor, with equal spacing between two adjacent permanent magnets.

[0019] There is an air gap between the surface of the permanent magnet facing the stator and the stator teeth, and the ratio between the radial dimension of the permanent magnet along the rotor and the radial dimension of the air gap along the rotor is 5 to 8.

[0020] The beneficial effects of the embodiments of this application, which differ from the prior art, are as follows: This application provides a permanent magnet servo motor, which includes a stator, an armature winding, multiple permanent magnets, a rotor, and a shaft. The rotor surrounds the outside of the shaft, and the stator surrounds the outside of the rotor and is spaced apart from the rotor. Multiple permanent magnets are disposed on the rotor and located between the rotor and the stator. The armature winding is disposed on the stator. The stator teeth of the stator include multiple wide teeth and multiple narrow teeth. The multiple wide teeth and multiple narrow teeth are each in pairs, and the multiple wide tooth groups and multiple narrow tooth groups are equidistantly distributed and alternately distributed along the circumference of the stator. By configuring the stator teeth to include multiple wide teeth and multiple narrow teeth, with each pair of wide teeth forming a group, and the wide tooth groups and narrow tooth groups being equidistantly distributed along the circumference of the stator, the magnetic field distribution of the permanent magnet servo motor can be optimized, effectively reducing low-order harmonics. This reduces the residual low-order harmonic components in the cogging torque, thereby not only improving the uniformity of the air gap magnetic flux density distribution and reducing hysteresis loss and eddy current loss in the iron core, but also effectively suppressing cogging torque, reducing torque pulsation, and improving the smoothness of permanent magnet servo motor operation. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein: Figure 1 This is a cross-sectional structural schematic diagram of an embodiment of the permanent magnet servo motor proposed in this application; Figure 2 This is a diagram showing the distribution of magnetic field lines of the permanent magnet servo motor under no-load conditions as proposed in this application. Figure 3 This is a comparison diagram of the no-load back electromotive force waveforms of the permanent magnet servo motor proposed in this application and a traditional permanent magnet servo motor; Figure 4 This is a comparison diagram of the harmonics of the no-load back EMF Fourier decomposition of the permanent magnet servo motor proposed in this application and the traditional permanent magnet servo motor. Detailed Implementation

[0022] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. It is understood that the specific embodiments described herein are only for explaining this application and not for limiting it. Furthermore, it should be noted that, for ease of description, only the parts related to this application are shown in the accompanying drawings, not all structures. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0023] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0024] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0025] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0026] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0027] This application provides a permanent magnet servo motor 100. For example... Figures 1 to 4 As shown, the permanent magnet servo motor 100 includes a stator 10, an armature winding 20, multiple permanent magnets 30, a rotor 40, and a shaft 50. The rotor 40 surrounds the outside of the shaft 50, the stator 10 surrounds the outside of the rotor 40 and is spaced apart from the rotor 40, the multiple permanent magnets 30 are disposed on the rotor 40 and located between the rotor 40 and the stator 10, and the armature winding 20 is disposed on the stator 10. The stator teeth 11 of the stator 10 include multiple wide teeth 111 and multiple narrow teeth 112. The multiple wide teeth 111 and the multiple narrow teeth 112 are each grouped in pairs, and the multiple wide tooth groups 111a and the multiple narrow tooth groups 112a are equidistantly distributed along the circumference of the stator 10.

[0028] By configuring the stator teeth 11 of the stator 10 to include multiple wide teeth 111 and multiple narrow teeth 112, with each pair of wide teeth 111 and narrow teeth 112 forming a group, and the wide tooth groups 111a and narrow tooth groups 112a being equidistantly and alternately distributed along the circumference of the stator 10, the magnetic field distribution of the permanent magnet servo motor 100 can be optimized, effectively reducing low-order harmonics. This reduces the residual low-order harmonic components in the cogging torque, thereby not only improving the uniformity of the air gap magnetic flux density distribution and reducing hysteresis and eddy current losses in the core, but also effectively suppressing cogging torque, reducing torque pulsation, and improving the smoothness of the permanent magnet servo motor 100's operation. Simultaneously, the distribution of the stator teeth 11 can also effectively reduce back electromotive force harmonics, lower the distortion rate of the back electromotive force output waveform, and improve the sinusoidal nature of the back electromotive force output waveform.

[0029] The rotor 40 surrounds the outer side of the shaft 50, and a permanent magnet 30 is disposed on the rotor 40, forming the main magnetic poles. The rotor 40 is sleeved on the shaft 50, which provides axial and radial support to the rotor 40 and transmits the torque generated by the rotor 40 to the load. A rigid connection can be formed between the rotor 40 and the shaft 50, allowing them to rotate synchronously. This enables the electromagnetic torque generated by the rotor 40 to be efficiently transmitted to the shaft 50 and facilitates precise closed-loop control. The rigid connection between the rotor 40 and the shaft 50 can be an interference fit, key connection, pin connection, or screw connection, but is not limited to these methods.

[0030] The permanent magnet servo motor 100 includes multiple permanent magnets 30, which are equidistantly spaced along the circumference of the rotor 40. The permanent magnets 30 are positioned on the surfaces of the rotor 40 opposite to the stator 10, and can be adhesively attached to the outer surface of the rotor 40 near the stator 10. This structure shortens the magnetic flux path and reduces magnetic resistance, thereby improving magnetic flux utilization. Before attaching the permanent magnets 30 to the outer surface of the rotor 40 near the stator 10, the outer surface of the rotor 40 and the surface on which the permanent magnets 30 will be attached can be pre-treated, such as by cleaning and roughening, to enhance the adhesion of the permanent magnets 30. After attachment, curing can be performed in a high-temperature oven to enhance the bonding strength of the permanent magnets 30. The adhesive used to attach the permanent magnets 30 to the rotor 40 can be epoxy resin or acrylic adhesive, but is not limited to these.

[0031] The permanent magnet 30 includes multiple pairs of magnetic poles 31. These pairs of poles 31 are evenly spaced along the circumference of the rotor 40. Each pair of poles 31 includes two adjacent permanent magnets 30 with opposite magnetic properties. One permanent magnet 30 in each pair of poles 31 is the south pole (S pole), and the other is the north pole (N pole), forming a mutually attractive magnetic circuit. The distance between the south and north poles in each pair of poles 31 is equal to the distance between adjacent pairs of poles 31. That is, the south and north poles are evenly spaced and alternately distributed along the circumference of the rotor 40, resulting in the permanent magnets 30 being distributed in the form NSNS…NS, thereby forming a complete rotating magnetic field around the rotor 40. In some embodiments, the permanent magnet 30 can be a neodymium iron boron permanent magnet, a samarium cobalt permanent magnet, an iron oxide permanent magnet, an alnico permanent magnet, or a samarium iron nitride permanent magnet, but is not limited thereto. Preferably, the permanent magnet 30 is a neodymium iron boron permanent magnet.

[0032] The stator 10 surrounds the permanent magnet 30 and the rotor 40. Specifically, the stator 10 includes multiple stator teeth 11 and a stator yoke 13. The stator yoke 13 surrounds the permanent magnet 30 and the rotor 40. The multiple stator teeth 11 are equidistantly spaced along the circumference of the stator yoke 13 on the side of the stator yoke 13 closest to the permanent magnet 30 and the rotor 40, that is, on the inner side of the stator yoke 13. The stator teeth 11 include multiple wide tooth groups 111a and multiple narrow tooth groups 112a. The multiple wide tooth groups 111a and the multiple narrow tooth groups 112a are equidistantly and alternately distributed along the circumference of the stator 10. Each wide tooth group 111a includes two wide teeth 111, and each narrow tooth group 112a includes two narrow teeth 112. The stator teeth 11 are distributed in a periodic pattern, with each cycle consisting of a wide tooth group 111a and a narrow tooth group 112a, specifically in the form of "wide tooth 111-wide tooth 111-narrow tooth 112-narrow tooth 112". Along the circumference of the stator 10, the tooth body size of the wide tooth 111 is larger than that of the narrow tooth 112, that is, along the circumference of the stator 10, the angle covered by the tooth body of the wide tooth 111 is greater than the angle covered by the tooth body of the narrow tooth 112.

[0033] The armature winding 20 is wound around the teeth of the wide tooth 111 and the narrow tooth 112. When an external power source supplies current to the armature winding 20, a rotating magnetic field is generated. This rotating magnetic field interacts with the permanent magnet 30 to generate an electromagnetic force. The electromagnetic force acts on the rotor 40 to form an electromagnetic torque that drives the rotor 40 to rotate. The rotor 40 transmits the rotational motion through the shaft 50, thereby outputting mechanical torque and completing the conversion from electrical energy to mechanical energy.

[0034] In some embodiments, the rotor 40 is provided with a plurality of auxiliary slots 41, and the plurality of auxiliary slots 41 correspond one-to-one with a plurality of permanent magnets 30.

[0035] Each auxiliary slot 41 has a corresponding permanent magnet 30 on the side facing the stator 10, and the projection of the permanent magnet 30 on the rotor 40 completely covers the slot opening 41a of the auxiliary slot 41. The circumferential dimension of the slot opening 41a of the auxiliary slot 41 along the rotor 40 is smaller than the circumferential dimension of the permanent magnet 30 along the rotor 40, so that each permanent magnet 30 can be stably fixed to the outer surface of the rotor 40, improving the connection strength and stability between the permanent magnet 30 and the rotor 40.

[0036] The permanent magnet 30 is spaced apart from the stator teeth 11, so that an air gap 30a is formed between the surface of the permanent magnet 30 facing the stator 10 and the stator teeth 11. Figure 2 As shown, the magnetic path of the permanent magnet flux sequentially reaches the air gap 30a, stator teeth 11 (wide teeth 111 or narrow teeth 112), stator yoke 13, stator teeth 11 (narrow teeth 112 or wide teeth 111), air gap 30a, and the S pole of the permanent magnet 30 through the N pole of the permanent magnet 30, and then returns to the N pole of the permanent magnet 30 through the rotor 40 to form a closed loop.

[0037] Since the permanent magnet 30 is the source of the magnetic field of the permanent magnet servo motor 100, the side of the permanent magnet 30 facing the rotor 40 is the area through which the main magnetic flux flows. By opening an auxiliary slot 41 on the rotor 40 and making the auxiliary slot 41 correspond to the permanent magnet 30, the magnetic permeability distribution on the side of the permanent magnet 30 facing the rotor 40 can be adjusted, thereby achieving precise control of the air gap magnetic flux density waveform. This not only reduces the distortion rate of the back electromotive force output waveform and improves the sinusoidal shape of the waveform, but also reduces the amplitude of the magnetic reluctance change, making the magnetic field energy change more smoothly with the position of the rotor 40. This effectively suppresses cogging torque and reduces torque pulsation, which helps to improve the smoothness of the permanent magnet servo motor 100's operation and enhances the adaptability of the permanent magnet servo motor 100 under overload conditions.

[0038] like Figures 3 to 4 As shown, by alternating wide tooth groups 111a and narrow tooth groups 112a at equal intervals along the circumference of the stator 10, and by opening multiple auxiliary slots 41 on the rotor 40 corresponding one-to-one with multiple permanent magnets 30, it is possible not only to reduce the distortion rate of the back electromotive force output waveform and improve the sinusoidal shape of the waveform, but also to effectively weaken odd harmonics, thereby reducing or eliminating additional losses and torque pulsation.

[0039] Furthermore, by equidistantly alternating wide tooth groups 111a and narrow tooth groups 112a along the circumference of the stator 10, and by opening multiple auxiliary slots 41 on the rotor 40 corresponding one-to-one with the multiple permanent magnets 30, the leakage flux coefficient can be reduced and the leakage flux path can be blocked, thus eliminating the need to reduce magnetic flux leakage by setting pole shoes. That is, no pole shoes are required on either side of the stator 10 along the circumference of the stator 10 at the end of each stator tooth 11 away from the stator yoke 13. On the one hand, this not only simplifies the manufacturing process and processing steps of the stator 10, but also makes it easier to wind the coil of the armature winding 20, improving the winding efficiency and thus improving the overall production efficiency of the permanent magnet servo motor 100. On the other hand, the absence of pole shoes allows for a larger space between two adjacent stator teeth 11, increasing the slot fill factor, and reducing the length of the magnetic flux path, thereby reducing the magnetic reluctance of the permanent magnet servo motor 100.

[0040] In some embodiments, the total number of stator teeth 11 is P. S Among them, the number of wide teeth 111 is m, and the number of narrow teeth 112 is n; the number of magnetic pole pairs 31 of permanent magnet 30 is P. m The number of auxiliary slots 41 on rotor 40 is Z, which satisfies the relationship: m=n=P S / 2, Z=2P m For example, the total number of stator teeth 11 is 12, the number of wide teeth 111 is 5, the number of narrow teeth 112 is 5, the number of magnetic pole pairs 31 is 5, and the number of auxiliary slots 41 is 10.

[0041] In some embodiments, the central axis of the auxiliary slot 41 along the circumferential direction of the rotor 40 coincides with the central axis of the corresponding permanent magnet 30 along the circumferential direction of the rotor 40. This further optimizes the magnetic field distribution, thereby not only reducing the distortion rate of the back electromotive force output waveform but also making the air gap magnetic flux density distribution more uniform, without areas of excessively high or low density. This effectively reduces hysteresis losses and eddy current losses in the core, improving efficiency.

[0042] In some embodiments, the maximum dimension of the auxiliary slot 41 along the circumference of the rotor 40 is less than or equal to the dimension of the permanent magnet 30 along the circumference of the rotor 40. Understandably, the auxiliary slot 41 has multiple dimensions along the circumference of the rotor 40, with the largest dimension being less than or equal to the dimension of the permanent magnet 30 along the circumference of the rotor 40. This ensures that the rotor 40 has sufficient strength to support the permanent magnet 30, thereby improving overload capacity while minimizing iron losses in the permanent magnet servo motor 100 and ensuring smooth operation of the permanent magnet servo motor 100.

[0043] In some embodiments, the slot 41a of the auxiliary slot 41 is located on the outer surface of the rotor 40, and the circumferential dimension of the slot 41a along the rotor 40 is less than or equal to 50% of the distance between two adjacent permanent magnets 30, so as to ensure that the permanent magnets 30 can be stably placed on the outer surface of the rotor 40.

[0044] The circumferential dimension of the slot 41a along the rotor 40 can be 50%, 48.8%, 45%, 43%, 41.5%, 40%, 39%, 36.6%, 35%, 34.5%, 32%, 30%, 28.5%, 26%, 25.3%, 22%, 20%, 18%, 16.5%, 15%, 13%, 10%, 9.5%, 8%, 5%, 2%, etc., of the distance between two adjacent permanent magnets 30, but is not limited to these. The specific ratio can be selected according to actual needs.

[0045] In some embodiments, each auxiliary slot 41 includes a plurality of interconnected sub-auxiliary slots 411. The number of sub-auxiliary slots 411 in each auxiliary slot 41 is 2 to 3. The dimensions of the plurality of sub-auxiliary slots 411 along the radial direction of the rotor 40 may be unequal, and their dimensions along the circumferential direction of the rotor 40 may also be unequal. In the radial direction of the rotor 40, the dimensions of the plurality of sub-auxiliary slots 411 decrease in a stepped manner from the inside to the outside, and the difference between the radial dimensions of two adjacent sub-auxiliary slots 411 is 0.3 mm to 0.8 mm. That is, in the two adjacent sub-auxiliary slots 411, the radial dimension of the sub-auxiliary slot 411 closer to the rotating shaft 50 along the rotor 40 is 0.3mm~0.8mm larger than the radial dimension of the sub-auxiliary slot 411 closer to the stator 10 along the rotor 40. This allows the magnetic reluctance change to be gradient transition, avoiding harmonic superposition caused by abrupt changes in magnetic permeability, thereby more effectively canceling low-order harmonics. This not only improves the uniformity of air gap magnetic flux density distribution and reduces hysteresis loss and eddy current loss in the iron core, but also makes the suppression effect of cogging torque more significant, improves the smoothness of the permanent magnet servo motor 100 movement, and reduces additional iron loss caused by vibration.

[0046] In the radial direction of the rotor 40, the difference between the dimensions of two adjacent sub-auxiliary slots 411 along the radial direction of the rotor 40 can be 0.3mm, 0.33mm, 0.38mm, 0.4mm, 0.42mm, 0.45mm, 0.488mm, 0.5mm, 0.525mm, 0.55mm, 0.575mm, 0.59mm, 0.6mm, 0.615mm, 0.65mm, 0.68mm, 0.7mm, 0.73mm, 0.755mm, 0.785mm, 0.8mm, etc., but is not limited to these. The specific difference can be selected according to actual needs.

[0047] The dimensions of multiple sub-auxiliary slots 411 decrease in a stepped manner from the inside to the outside along the circumferential direction of the rotor 40, which can divert high-frequency magnetic flux, reduce eddy current losses, and thus improve the problem of excessive local losses caused by magnetic flux concentration.

[0048] The inner wall of the auxiliary groove 41 is arc-shaped. Specifically, the corner areas of the sub-auxiliary groove 411 can be arc-shaped, and the connection between two adjacent sub-auxiliary grooves 411 can also be arc-shaped. By making the inner wall of the auxiliary groove 41 arc-shaped, combined with the structure of the auxiliary groove 41, eddy current losses can be further reduced.

[0049] This embodiment of the application can effectively suppress cogging torque, reduce iron loss and improve the overload capacity of permanent magnet servo motor 100 by adjusting the number of sub-auxiliary slots 411 of each auxiliary slot 41 and the difference between the radial dimensions of two adjacent sub-auxiliary slots 411 along the rotor 40, thus solving the defect of traditional motors that are difficult to balance multiple performance indicators.

[0050] In some embodiments, the cross-sections of both the wide teeth 111 and the narrow teeth 112 are trapezoidal, and in the radial direction of the stator 10, the dimensions of both the wide teeth 111 and the narrow teeth 112 gradually increase from the inside to the outside along the circumferential direction of the stator 10. That is, the dimensions of both the wide teeth 111 and the narrow teeth 112 in the circumferential direction of the stator 10 gradually decrease from the end near the stator yoke 13 to the end away from the stator yoke 13 in the radial direction of the stator 10. This structure can significantly increase the mechanical strength of the wide teeth 111 and the narrow teeth 112, allowing the stress to decrease smoothly from the end of the wide teeth 111 and the narrow teeth 112 near the stator yoke 13 to the end away from the stator yoke 13, avoiding stress concentration at the end of the wide teeth 111 and the narrow teeth 112 near the stator yoke 13, thus greatly reducing stress deformation under the same force, which is beneficial for reducing torque pulsation and noise of the permanent magnet servo motor 100. Furthermore, by designing the wide teeth 111 and the narrow teeth 112 as trapezoidal teeth, the magnetic resistance of the teeth can be reduced by optimizing the tooth shape, thereby reducing tooth loss and improving the efficiency of the permanent magnet servo motor 100. Compared with rectangular teeth, the magnetic circuit of trapezoidal teeth is more optimized, which can effectively reduce energy loss.

[0051] In some embodiments, at the same radial dimension of the stator 10, the ratio between the circumferential dimension of the wide tooth 111 along the stator 10 and the circumferential dimension of the narrow tooth 112 along the stator 10 is 1.1 to 1.6.

[0052] The wide tooth 111 has the same shape as the narrow tooth 112, and the radial dimension of the wide tooth 111 along the stator 10 is equal to the radial dimension of the narrow tooth 112 along the stator 10. The circumferential dimension of the wide tooth 111 along the stator 10 is greater than the circumferential dimension of the narrow tooth 112 along the stator 10. That is, at the same radial dimension of the stator 10, the circumferential dimension of the wide tooth 111 along the stator 10 is greater than the circumferential dimension of the narrow tooth 112 along the stator 10.

[0053] By limiting the ratio between the circumferential dimension of the wide tooth 111 and the circumferential dimension of the narrow tooth 112 of the stator 10 at the same radial dimension of the stator 10 to the range of 1.1 to 1.6, on the one hand, the cogging torque can be significantly reduced, thereby effectively improving the smoothness of the permanent magnet servo motor 100 operation; on the other hand, the back electromotive force harmonics can be effectively reduced, the distortion rate of the back electromotive force output waveform can be reduced, and the sinusoidal nature of the back electromotive force output waveform can be improved.

[0054] In some embodiments, at the same radial dimension of the stator 10, the ratio between the circumferential dimension of the wide tooth 111 along the stator 10 and the circumferential dimension of the narrow tooth 112 along the stator 10 can be 1.1, 1.15, 1.18, 1.2, 1.235, 1.25, 1.288, 1.3, 1.335, 1.35, 1.37, 1.4, 1.44, 1.46, 1.49, 1.5, 1.52, 1.55, 1.565, 1.58, 1.6, etc., but is not limited to these; the specific ratio can be selected according to actual needs.

[0055] In some embodiments, the ratio between the circumferential dimension of the wide tooth 111 near the rotor 40 along the stator 10 and the circumferential dimension of the wide tooth 111 away from the rotor 40 along the stator 10 is 0.6 to 0.8; the ratio between the circumferential dimension of the narrow tooth 112 near the rotor 40 and the circumferential dimension of the narrow tooth 112 away from the rotor 40 along the stator 10 is 0.6 to 0.8. The larger circumferential dimensions of the wide tooth 111 and the narrow tooth 112 away from the rotor 40 along the stator 10 provide sufficient magnetic circuit cross-sectional area, reduce tooth magnetic voltage drop, and reduce local magnetic saturation. The smaller circumferential dimensions of the wide tooth 111 and the narrow tooth 112 near the rotor 40 along the stator 10 reduce magnetic leakage and improve the utilization rate of the magnetic field generated by the permanent magnet 30, thereby improving the efficiency of the permanent magnet servo motor 100.

[0056] The ratio between the circumferential dimension of the end of the wide tooth 111 near the rotor 40 along the stator 10 and the circumferential dimension of the end of the wide tooth 111 away from the rotor 40 along the stator 10, and the ratio between the circumferential dimension of the end of the narrow tooth 112 near the rotor 40 and the circumferential dimension of the end of the narrow tooth 112 away from the rotor 40 along the stator 10, can be determined by the receiving groove 12 formed between two adjacent stator teeth 11. The stator teeth 11 on both sides of the receiving groove 12 may be three combinations: wide tooth 111 and narrow tooth 112, wide tooth 111 and wide tooth 111, and narrow tooth 112 and narrow tooth 112. The selection of the ratio needs to ensure that the shape of the receiving groove 12 is the same under the three combinations; otherwise, it will greatly increase the difficulty of processing and manufacturing. By limiting the above ratio to the range of 0.6 to 0.8, the processing and manufacturing difficulty of stator 10 can be effectively reduced and production efficiency can be improved. Specific ratios can be 0.6, 0.62, 0.633, 0.65, 0.68, 0.7, 0.732, 0.75, 0.77, 0.785, 0.8, etc., but are not limited to these. The specific ratio can be selected according to actual needs.

[0057] In some embodiments, a receiving groove 12 is formed between two adjacent stator teeth 11, which is used to accommodate the armature winding 20. In the radial direction of the stator 10, the size of the receiving groove 12 gradually increases from the inside to the outside along the circumferential direction of the stator 10, so that the opening width of the receiving groove 12 is smaller than the bottom width of the receiving groove 12. This allows the end of the stator tooth 11 near the rotor 40 to firmly fix the armature winding 20 in the receiving groove 12, reducing the risk of loosening or displacement of the armature winding 20 due to vibration or impact during the operation of the permanent magnet servo motor 100, and further improving the smoothness of the operation of the permanent magnet servo motor 100.

[0058] In some embodiments, the magnetism of a plurality of permanent magnets 30 is alternately arranged along the circumference of the rotor 40, and each permanent magnet 30 has the same circumferential dimension along the rotor 40, the same radial dimension along the rotor 40, and the interval between two adjacent permanent magnets 30 is equal.

[0059] The rotor 40 of the permanent magnet servo motor 100 is provided with multiple permanent magnets 30, which are arranged alternately along the circumferential direction to form an alternating N-pole and S-pole magnetic pole structure, and two adjacent N-pole and S-pole form a pair of magnetic poles 31. Among the multiple permanent magnets 30, each permanent magnet 30 has the same radial dimension along the rotor 40, so that the interval between each permanent magnet 30 and the stator teeth 11 is also equal.

[0060] By ensuring that each permanent magnet 30 has the same circumferential dimension along the rotor 40, the same radial dimension along the rotor 40, and the same spacing between adjacent permanent magnets 30, the consistency of the permanent magnet 30's dimensions and the spacing between adjacent permanent magnets 30 can be guaranteed. On the one hand, this optimizes the magnetic pole distribution and reduces the distortion rate of the back electromotive force output waveform; on the other hand, it ensures balanced magnetic reluctance between magnetic poles, reducing vibration and noise caused by magnetic circuit imbalance; furthermore, it facilitates the standardization of permanent magnets 30 for mass production, while ensuring the balance of the rotor 40 during rotation, thus helping to improve the operational stability of the permanent magnet servo motor 100.

[0061] In some embodiments, an air gap 30a is formed between the surface of the permanent magnet 30 facing the stator 10 and the stator teeth 11. The distance between the rotor 40 and the stator teeth 11 is greater than the radial dimension of the permanent magnet 30 along the rotor 40, so that an air gap 30a is formed between the surface of the permanent magnet 30 facing the stator 10 and the stator teeth 11. The ratio between the radial dimension of the permanent magnet 30 along the rotor 40 and the radial dimension of the air gap 30a along the rotor 40 is 5 to 8. For example, the ratio between the radial dimension of the permanent magnet 30 along the rotor 40 and the radial dimension of the air gap 30a along the rotor 40 can be 5, 5.15, 5.2, 5.55, 5.8, 6, 6.5, 6.66, 6.9, 7, 7.35, 7.5, 7.88, 8, etc., but is not limited to these; the specific ratio can be selected according to actual needs.

[0062] By limiting the ratio between the radial dimension of the permanent magnet 30 along the rotor 40 and the radial dimension of the air gap 30a along the rotor 40 to a range of 5 to 8, the magnetic flux density of the air gap 30a of the permanent magnet servo motor 100 is made more stable. This not only avoids the concentration of magnetic leakage caused by the permanent magnet 30 being too thin, but also avoids the edge magnetic leakage caused by the permanent magnet 30 being too thick.

[0063] Unlike existing technologies, the permanent magnet servo motor of this application includes a stator, an armature winding, multiple permanent magnets, a rotor, and a shaft. The rotor surrounds the outside of the shaft, and the stator surrounds the outside of the rotor and is spaced apart from the rotor. Multiple permanent magnets are disposed on the rotor and located between the rotor and the stator, and the armature winding is disposed on the stator. The stator teeth include multiple wide teeth and multiple narrow teeth, each group consisting of two wide teeth and multiple narrow teeth, which are equidistantly and alternately distributed along the circumference of the stator. By configuring the stator teeth in the above manner, including multiple wide teeth and multiple narrow teeth, with each pair of wide teeth forming a group, and the wide tooth groups and narrow tooth groups being equidistantly distributed along the circumference of the stator, the magnetic field distribution of the permanent magnet servo motor can be optimized, effectively weakening low-order harmonics. This reduces the residual low-order harmonic components in the cogging torque, thereby not only improving the uniformity of the air gap magnetic flux density distribution and reducing hysteresis loss and eddy current loss in the iron core, but also effectively suppressing cogging torque, reducing torque pulsation, and improving the smoothness of permanent magnet servo motor operation.

[0064] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A permanent magnet servo motor, characterized in that, It includes a stator, an armature winding, multiple permanent magnets, a rotor, and a shaft. The rotor surrounds the outside of the shaft, the stator surrounds the outside of the rotor and is spaced apart from the rotor, the multiple permanent magnets are disposed on the rotor and located between the rotor and the stator, and the armature winding is disposed on the stator. The stator teeth of the stator include multiple wide teeth and multiple narrow teeth. The multiple wide teeth and the multiple narrow teeth are each in pairs, and the multiple wide teeth groups and the multiple narrow teeth groups are distributed alternately at equal intervals along the circumference of the stator.

2. The permanent magnet servo motor according to claim 1, characterized in that, The rotor is provided with multiple auxiliary slots, and each of the multiple auxiliary slots corresponds to one of the multiple permanent magnets.

3. The permanent magnet servo motor according to claim 2, characterized in that, The auxiliary slot along the circumferential central axis of the rotor coincides with the corresponding permanent magnet along the circumferential central axis of the rotor.

4. The permanent magnet servo motor according to claim 2, characterized in that, The maximum dimension of the auxiliary slot along the circumference of the rotor is less than or equal to the dimension of the permanent magnet along the circumference of the rotor.

5. The permanent magnet servo motor according to claim 2, characterized in that, The slot opening of the auxiliary groove is located on the outer surface of the rotor, and the circumferential dimension of the slot opening is less than or equal to 50% of the distance between two adjacent permanent magnets.

6. The permanent magnet servo motor according to any one of claims 2 to 5, characterized in that, Each of the aforementioned auxiliary slots includes multiple interconnected sub-auxiliary slots; In the radial direction of the rotor, the dimensions of the plurality of sub-auxiliary slots decrease in a stepped manner from the inside to the outside; and / or, the dimensions of the plurality of sub-auxiliary slots decrease in a stepped manner from the inside to the outside in the circumferential direction of the rotor.

7. The permanent magnet servo motor according to claim 6, characterized in that, The difference in the radial dimension of two adjacent auxiliary slots along the rotor is 0.3 mm to 0.8 mm.

8. The permanent magnet servo motor according to claim 6, characterized in that, The number of sub-auxiliary slots in each of the aforementioned auxiliary slots is 2 to 3.

9. The permanent magnet servo motor according to any one of claims 2 to 5, characterized in that, The inner wall of the auxiliary groove is arc-shaped.

10. The permanent magnet servo motor according to claim 1, characterized in that, Both the wide teeth and the narrow teeth have trapezoidal cross-sections, and in the radial direction of the stator, the dimensions of both the wide teeth and the narrow teeth gradually increase from the inside to the outside along the circumferential direction of the stator.

11. The permanent magnet servo motor according to claim 10, characterized in that, At the same radial dimension of the stator, the ratio between the dimension of the wide tooth along the circumference of the stator and the dimension of the narrow tooth along the circumference of the stator is 1.1 to 1.

6.

12. The permanent magnet servo motor according to claim 10, characterized in that, The ratio between the circumferential dimension of the wide tooth at the end near the rotor along the stator and the circumferential dimension of the wide tooth at the end away from the rotor along the stator is 0.6 to 0.

8. The ratio between the circumferential dimension of the narrow tooth at the end closest to the rotor along the stator and the circumferential dimension of the narrow tooth at the end furthest from the rotor along the stator is 0.6 to 0.

8.

13. The permanent magnet servo motor according to claim 1, characterized in that, A receiving slot is formed between two adjacent stator teeth, the receiving slot being used to accommodate the armature winding; In the radial direction of the stator, the accommodating groove gradually increases in size from the inside to the outside along the circumferential direction of the stator.

14. The permanent magnet servo motor according to claim 1, characterized in that, The magnetism of the plurality of permanent magnets is arranged alternately along the circumference of the rotor, and each permanent magnet has the same circumferential dimension and the same radial dimension along the rotor, and the interval between two adjacent permanent magnets is equal.

15. The permanent magnet servo motor according to claim 1, characterized in that, There is an air gap between the surface of the permanent magnet facing the stator and the stator teeth, and the ratio between the radial dimension of the permanent magnet along the rotor and the radial dimension of the air gap along the rotor is 5 to 8.

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