Functional outer diameter unequal-thickness magnetic ring and magnetizing method thereof

Abstract

The invention relates to a functional outer diameter unequal-thickness magnet ring and a magnetizing method thereof, and belongs to the technical field of permanent magnet motors, the inner diameter of the unequal-thickness magnet ring is circular, the outer diameter of the unequal-thickness magnet ring is a changing curve, the thickness of the changing curve of the outer diameter at a main magnetic pole part is unchanged, and the thickness of the changing curve of the outer diameter at a transition position between adjacent main magnetic pole parts is reduced; the unequal-thickness magnetic rings are made of bonded neodymium iron boron materials. The magnetic ring is composed of a bonded neodymium iron boron magnetic ring with a functional outer diameter and a multi-pole magnetizing clamp matched with the magnetic ring, the outer diameter of the magnetic ring adopts two functional sizes, and the amplitude of cogging torque is reduced by reducing the thickness of a magnetic pole transition area and regulating and controlling harmonic components of surface magnetism of the magnetic ring. The multi-pole magnetizing iron core matched with the magnetizing clamp can magnetize the magnetic ring into a plurality of magnetic poles which are alternately distributed on the surface.

Description

Technical Field

[0001] The invention relates to a functionalized outer diameter unequal thickness magnetic ring and a magnetizing method thereof, belonging to the technical field of permanent magnet motors. Background Art

[0002] A permanent magnet motor is a motor that uses permanent magnets to generate a magnetic field and is usually used to convert electrical energy into mechanical energy. Compared with traditional motors, permanent magnet motors do not need to provide current for excitation, thus reducing power loss and having higher efficiency, especially at medium and low speeds. Compared with traditional motors, permanent magnet motors can achieve smaller size and lighter weight, and are particularly suitable for applications that have high weight and space requirements while requiring high power output, such as electric vehicles, aerospace and other fields.

[0003] With the continuous growth of industrial development, various fields have put forward higher requirements for the performance of micro motors. Among them, lower torque ripple is one of the conditions to ensure the stability of micro motors at high speed and high power. Torque ripple is the torque fluctuation caused by electromagnetic reasons during the operation of the motor, which is manifested as periodic fluctuation of the output torque. Torque ripple is mainly caused by cogging torque and current harmonics. Cogging torque is the torque fluctuation caused by the change of magnetic resistance between permanent magnets and stator teeth, and the interaction between current harmonics and surface magnetic flux density harmonics of permanent magnets will also produce torque fluctuations.

[0004] Torque ripple affects the smooth operation of the motor, especially in applications that require precise control, such as robots, servo motors, and electric vehicles. At the same time, torque ripple reduces efficiency and accuracy. Due to the existence of torque ripple, the motor will generate unnecessary vibration and noise during operation, resulting in energy loss. For applications that require high-precision position control, torque ripple will also reduce the positioning accuracy and responsiveness of the system.

[0005] At present, one of the main methods to reduce torque pulsation is to reduce the cogging torque. The main methods include optimizing the slot-pole ratio, skew slot design, permanent magnet segmentation and skew pole design, etc. However, some obvious problems have emerged in long-term market applications:

[0006] 1. The method of optimizing the slot-pole ratio does not require complex modifications to the stator or rotor structure, but certain specific application requirements limit the range of optional slot-pole ratios, and it is always impossible to find an ideal combination. At the same time, optimizing the slot-pole ratio has limited comprehensive optimization of performance. Although it can reduce the cogging torque, it may not necessarily optimize other performance of the motor (such as efficiency, output power, etc.);

[0007] 2. The skewed slot design method disperses the fluctuation of the cogging torque to a wider angle range by beveling the stator slots, thereby reducing the amplitude of the cogging torque. However, the skewed slot design increases the difficulty and cost of stator processing, especially in motors with high power or high precision requirements, where the impact of processing errors is greater. At the same time, the skewed slot may increase the electromagnetic noise and eddy current loss of the motor, and is not conducive to the heat dissipation of the stator.

[0008] 3. Segmented or skewed permanent magnet design: By segmenting or setting the permanent magnet to skewed poles, the change in magnetic resistance can be effectively smoothed, thereby significantly reducing the cogging torque. However, the design and manufacturing of segmented or skewed permanent magnets are more complicated, and the assembly precision requirements are higher, which increases the difficulty and cost of production. Due to the segmentation or tilt of the permanent magnet, the utilization rate of the magnetic flux will decrease, which may affect the power density of the motor.

[0009] There is currently no good solution to the above problems. Summary of the invention

[0010] In view of the deficiencies in the prior art, the present invention provides a functionalized outer diameter unequal thickness magnetic ring and a magnetizing method thereof, so as to overcome the problems of cumbersome optimization process, complex processing and high assembly precision requirements in the prior art of optimizing torque pulsation.

[0011] The present invention adopts the following technical solution:

[0012] A functionalized outer diameter unequal thickness magnetic ring, wherein the inner diameter of the unequal thickness magnetic ring is circular, and the outer diameter is a changing curve, wherein the thickness of the changing curve of the outer diameter remains unchanged in the main magnetic pole part, and the thickness decreases at the transition position between adjacent main magnetic pole parts;

[0013] The unequal thickness magnetic rings are made of bonded NdFeB material.

[0014] Preferably, the first optimization function of the outer diameter of the unequal thickness magnetic ring can significantly reduce the higher harmonics of the surface magnetic waveform, thereby reducing the torque pulsation, and the outer diameter satisfies:

[0015] R0=(R1-H)+H×cos(nθ)

[0016] Among them, R0 is the outer diameter of the optimized magnetic ring; R1 is the outer diameter of the original magnetic ring; H is the pole cutting parameter, satisfying: R1-2H>R2, R2 is the inner diameter of the magnetic ring; H is determined by parameterized simulation; n is the number of magnetic poles; θ represents the circular angle, 0°<θ<360°.

[0017] Preferably, the second optimization function of the outer diameter of the unequal thickness magnetic ring significantly reduces the higher harmonics of the surface magnetic waveform, while the fundamental amplitude is higher than the first one, and the outer diameter satisfies:

[0018]

[0019] Among them, R0 is the outer diameter of the optimized magnetic ring; R1 is the outer diameter of the original magnetic ring; H is the pole cutting parameter, satisfying: R1-2H>R2, R2 is the inner diameter of the magnetic ring; H is determined by parameterized simulation; n is the number of magnetic poles; θ represents the circular angle, 0°<θ<360°.

[0020] The harmonics of the magnetic flux density waveform on the rotor surface have a significant impact on the torque pulsation of the permanent magnet motor. On the one hand, the magnetic flux density waveform affects the size of the cogging torque. On the other hand, the harmonics in the magnetic flux density waveform (especially the high-order harmonics) will cause the corresponding harmonic components in the electromagnetic torque. These harmonics will cause irregular fluctuations in the torque. The above reasons cause the motor to generate vibration and noise during operation, affecting the stability and operating efficiency of the motor. Therefore, in the design and operation of permanent magnet motors, suppressing the harmonic components in the magnetic flux density waveform, especially the high-order harmonics, is crucial to reducing torque pulsation and improving motor performance.

[0021] The present invention proposes a functionalized outer diameter unequal thickness magnetic ring and a corresponding magnetizing method, which consists of a bonded NdFeB magnetic ring with a functionalized outer diameter and a matching multi-pole magnetizing fixture. The outer diameter of the magnetic ring adopts two functionalized sizes, and the thickness of the magnetic pole transition zone is reduced to adjust the harmonic components of the magnetic ring surface magnetism and reduce the amplitude of the cogging torque. The multi-pole magnetizing core of the matching magnetizing fixture can magnetize the magnetic ring into a plurality of magnetic poles alternately distributed on the surface.

[0022] Preferably, when determining the pole cutting parameter H, according to the restriction of R1-2H>R2, in the finite element simulation, the value range of H is set to Set the value step size according to the solution requirements, solve all possible H values, and select the H value with the lowest surface magnetic harmonic distortion rate as the final result.

[0023] The above two outer diameter functions use the same clipping fundamental wave function cos(nθ). The difference is that the second clipping function adds the third harmonic cos(3nθ) on the basis of the first clipping function. Therefore, the fundamental wave amplitude of the second function is higher than that of the first one, and the motor output performance is better. However, due to the introduction of the third harmonic, the surface magnetic distortion rate is higher than that of the first one.

[0024] Preferably, during the production, the raw materials are first melted at a high temperature by casting or smelting to form an alloy; the raw materials are selected from high-purity neodymium iron boron and other elements, and usually a small amount of other elements (such as dysprosium, cerium, etc.) are added to improve the magnetic properties. After the alloy is cooled, it is crushed and ground to make a nano-scale powder; the nano-scale powder is mixed with a binder to obtain a mixture; the mixture is molded by a process such as pressing or injection molding to form a blank of the desired shape; the molded blank is cured at a specific temperature to fully cross-link the binder and enhance the mechanical strength of the magnet, and then the final product is obtained through post-processing, surface treatment and other processes.

[0025] Preferably, the adhesive is epoxy resin or polyurethane.

[0026] A magnetizing method for the functionalized outer diameter and unequal thickness magnetic ring based on the above-mentioned method, magnetizing is completed by means of a magnetizing fixture, the magnetizing fixture includes a base, a magnetizing core, a winding and a positioning device, the winding adopts enameled copper wire; the base and the positioning device adopt non-magnetic conductive materials;

[0027] During magnetization, place the magnetic ring on the magnetizing core and fix it with a positioning device. Connect the two ends of the winding to the positive and negative poles of the pulse power supply respectively, and then power on for magnetization. After power off, take out the magnetic ring structure to complete the magnetization.

[0028] Preferably, a groove is provided on the base, and the groove is used to place the magnetized core. A positioning column is provided at the center of the groove to position the magnetized core.

[0029] The magnetized core is provided with a through hole and a winding groove, and the winding groove is used to install the winding; a groove opening is provided between the winding groove and the through hole, and a magnetization position is formed between adjacent groove openings; the positioning device includes a disc and positioning plates evenly distributed around the disc, the disc is placed in the through hole on the magnetized core, and the positioning plates are stuck in the groove openings; the magnetic ring is sleeved in the positioning device, wherein the positioning plate corresponds to the transition position of the magnetic ring, and plays a role in limiting the circumferential rotation of the magnetic ring.

[0030] Preferably, the number of positioning plates is the same as the number of magnetic poles.

[0031] The magnetic ring of the present invention is equipped with a positioning device during magnetization to ensure that the magnetic poles are aligned with the fixture relative to each other, so as to ensure that the magnetization fixture can magnetize the magnetic ring into a designed low-harmonic magnetic circuit. Since the positioning device is not a mass-produced part, the positioning device is preferably made of non-magnetic materials such as nylon plastic, which is convenient for 3D printing.

[0032] For any details not provided in the present invention, please refer to the prior art.

[0033] The beneficial effects of the present invention are:

[0034] 1. In traditional sintered NdFeB surface-mounted motors, a single magnet is only distributed with a pair of magnetic poles. When performing operations such as pole cutting, defects such as broken corners and cracks are easily produced during processing, and the yield rate is difficult to guarantee. The present invention utilizes the advantages of bonded permanent magnet molding and directly designs the bonded NdFeB magnetic rings into a form with unequal outer diameters and thicknesses. The outer diameter function of the present invention can ensure that the unequal thickness magnetic ring structure has a surface magnetic waveform with a lower harmonic distortion rate. The first optimization function of the functionalized outer diameter and unequal thickness magnetic ring structure of the present invention satisfies the outer diameter: R0 = (R1-H) + H × cos (nθ), which can effectively reduce the higher harmonics of the surface magnetic waveform.

[0035] 2. The second optimization function of the functionalized outer diameter and unequal thickness magnetic ring structure of the present invention, the outer diameter satisfies: It can effectively reduce the higher harmonics of the surface magnetic waveform. The reduction effect is slightly worse than the first one, but it can ensure that the fundamental amplitude will not drop too much, which means that while reducing the torque pulsation, the motor outputs a larger average torque.

[0036] 3. The unequal thickness magnetic ring structure of the present invention has a positioning device to ensure that the center line of the magnetic pole is aligned with the center line of the tooth of the magnetizing fixture during the magnetization process, so as to ensure the effectiveness of the magnetization.

[0037] 4. The magnetic ring structure of the present invention is formed by pressing or injection molding, and the optimization and preparation process are simple, and the assembly accuracy requirement is not high. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The drawings in the specification, which constitute a part of the present application, are used to provide further understanding of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute improper limitations on the present application.

[0039] Figure 1 The outer diameter size of the magnetic ring with unequal thickness is the first optimization function;

[0040] Figure 2 Schematic diagram of the structure of the unequal thickness magnetic ring of the first optimization function, where (a) is a stereogram and (b) is a cross-sectional diagram;

[0041] Figure 3 It is a structural schematic diagram of the magnetizing fixture;

[0042] Figure 4 Schematic diagram of the structure of the positioning device, wherein (a) is a stereoscopic diagram of the positioning device, and (b) is a schematic diagram of the matching relationship between the positioning device and the magnetic ring;

[0043] Figure 5 Schematic diagram of the assembly process of the magnetizing fixture, wherein (a) is a three-dimensional diagram of the magnetizing core, and (b) is a schematic diagram of the matching relationship between the magnetizing core, the positioning device and the magnetic ring;

[0044] Figure 6 The outer diameter size of the magnetic ring with unequal thickness is the second optimization function;

[0045] Figure 7 Schematic diagram of the structure of the unequal thickness magnetic ring of the second optimization function, where (a) is a stereogram and (b) is a cross-sectional diagram;

[0046] Figure 8 A comparison diagram of the surface magnetic flux density waveforms of the magnetic ring optimized by the present invention and the magnetic ring with a traditional structure;

[0047] Fig. 9This is a comparison diagram of the surface magnetic harmonic distribution of the magnetic ring optimized by the present invention and the magnetic ring with traditional structure;

[0048] In the figure, 1-magnetic ring, 2-positioning device, 3-magnetic core, 4-winding, 5-base, 11-main magnetic pole part, 12-transition position, 21-positioning plate, 31-slot opening, 32-winding slot, 33-magnetizing position. DETAILED DESCRIPTION

[0049] In order to enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of the present invention are clearly and completely described below in conjunction with the drawings in the implementation of this specification, but are not limited to this. Anything not fully described in the present invention shall be based on the conventional technology in the art.

[0050] Example 1

[0051] A functionalized outer diameter unequal thickness magnetic ring, wherein the inner diameter of the unequal thickness magnetic ring is circular, and the outer diameter is a changing curve, wherein the thickness of the changing curve of the outer diameter remains unchanged in the main magnetic pole part, and the thickness decreases at the transition position between adjacent main magnetic pole parts;

[0052] The magnetic rings of different thickness are made of bonded NdFeB material.

[0053] The first optimization function for the outer diameter of magnetic rings of unequal thickness is as follows: Figure 1 , 2 As shown, it can significantly reduce the high-order harmonics of the surface magnetic waveform, thereby reducing the torque pulsation, and the outer diameter meets the following requirements:

[0054] R0=(R1-H)+H×cos(nθ)

[0055] Among them, R0 is the outer diameter of the optimized magnetic ring; R1 is the outer diameter of the original magnetic ring; H is the pole cutting parameter, satisfying: R1-2H>R2, R2 is the inner diameter of the magnetic ring; H is determined by parameterized simulation; n is the number of magnetic poles; θ represents the circular angle, 0°<θ<360°.

[0056] In this embodiment, the outer diameter of the original magnetic ring is R1=18.5 mm, R2=15.8 mm, and the number of magnetic poles is n=6. According to the first functionalized outer diameter formula:

[0057] R0=(R1-H)+H×cos(nθ)=(18.5-H)+H×cos(6θ)

[0058] At the same time, ensure that R1-2H>R2, that is, 18.5mm-2H>15.8mm, H<1.35mm

[0059] Through parametric finite element simulation, the value of H is directly set to 0mm, 0.1mm, 0.2mm...1.3mm in the existing finite element software for parallel solution, and the surface magnetic waveform in each case is obtained and the harmonics are decomposed. According to the results, when H = 0.6mm, the harmonic distortion rate of the surface magnetic waveform reaches the lowest value.

[0060] Therefore, the functionalized outer diameter R0 = 17.9 mm + 0.6 mm × cos (6θ), 0° < θ < 360°.

[0061] The cross section and three-dimensional structure of the magnetic ring processed according to the above outer diameter are as follows Figure 2 As shown in the figure, position 11 shows the main pole part of each magnetic pole, and position 12 shows the transition position 12 between adjacent main magnetic poles. It can be seen that the magnetic ring is thinned at the transition position 12 according to the first functionalized outer diameter to achieve the purpose of reducing the surface magnetic waveform harmonics and reducing torque pulsation.

[0062] Example 2

[0063] A functional outer diameter and unequal thickness magnetic ring, such as Figure 6 , 7 As shown in the figure, the second optimization function of the outer diameter of the unequal thickness magnetic ring significantly reduces the higher harmonics of the surface magnetic waveform. At the same time, the fundamental amplitude is higher than the first one, and the outer diameter satisfies:

[0064]

[0065] Among them, R0 is the outer diameter of the optimized magnetic ring; R1 is the outer diameter of the original magnetic ring; H is the pole cutting parameter, satisfying: R1-2H>R2, R2 is the inner diameter of the magnetic ring; H is determined by parameterized simulation; n is the number of magnetic poles; θ represents the circular angle, 0°<θ<360°.

[0066] In this embodiment, the outer diameter of the original magnetic ring is R1=18.5 mm, R2=15.8 mm, and the number of magnetic poles n=6. According to the second functional outer diameter formula:

[0067]

[0068] The function satisfies R1-2H>R2, that is, 18.5mm-2H>15.8mm, H<1.35mm

[0069] Through parametric finite element simulation, it is verified that when H = 0.9 mm, the harmonic distortion rate of the surface magnetic waveform reaches the lowest value. 0°<θ<360°.

[0070] Since the magnetic rings of the two outer diameter optimization functions use the same fundamental wave function, the maximum values ​​of the outer diameters are the same, and magnetization can be performed using a magnetization fixture of the same structure, simply by adjusting the position of the positioning plate.

[0071] The harmonics of the magnetic flux density waveform on the rotor surface have a significant impact on the torque pulsation of the permanent magnet motor. On the one hand, the magnetic flux density waveform affects the size of the cogging torque. On the other hand, the harmonics in the magnetic flux density waveform (especially the high-order harmonics) will cause the corresponding harmonic components in the electromagnetic torque. These harmonics will cause irregular fluctuations in the torque. The above reasons cause the motor to generate vibration and noise during operation, affecting the stability and operating efficiency of the motor. Therefore, in the design and operation of permanent magnet motors, suppressing the harmonic components in the magnetic flux density waveform, especially the high-order harmonics, is crucial to reducing torque pulsation and improving motor performance.

[0072] In the functionalized outer diameter and unequal thickness magnetic rings of Embodiments 1 and 2 of the present invention, the outer diameter of the magnetic ring adopts two functionalized sizes, and the thickness of the magnetic pole transition zone is reduced to adjust the harmonic components of the magnetic surface magnetism of the magnetic ring and reduce the amplitude of the cogging torque. The multi-pole magnetizing core of the matching magnetizing fixture can magnetize the magnetic ring into a plurality of magnetic poles alternately distributed on the surface.

[0073] The above two outer diameter functions use the same clipping fundamental wave function cos(nθ). The difference is that the second clipping function adds the third harmonic cos(3nθ) on the basis of the first clipping function. Therefore, the fundamental wave amplitude of the second function is higher than that of the first one, and the motor output performance is better. However, due to the introduction of the third harmonic, the surface magnetic distortion rate is higher than that of the first one.

[0074] The unequal thickness magnetic ring structure of the present invention has an outer diameter function that satisfies the first function R0=(R1-H)+H×cos(nθ), which can effectively reduce the high-order harmonics of the surface magnetic waveform. Figure 1 As shown in the schematic diagram of magnetic pole size, when the thickness of a single magnetic pole as shown by the dotted line remains the same, the magnetic flux density on both sides is often higher than that in the middle because the two sides of the magnetic pole are more likely to form a closed magnetic circuit with the adjacent magnetic poles, such as Figure 8 The outer diameter function of the present invention reduces the thickness of both sides of the magnetic pole, thereby reducing the magnetic flux on both sides of each magnetic pole, as shown in FIG. Fig. 9 As shown in the figure, after reducing the magnetic flux on both sides of each magnetic pole, the magnetic flux density in the middle position is higher, so the surface magnetic waveform is closer to a sine wave and the harmonic distortion rate is lower. The second function introduces the third harmonic on the basis of the first function. The winding current and the third harmonic will also generate torque, but the introduction of harmonics will also increase the harmonic distortion rate and cause motor vibration.

[0075] like Figure 8The figure shows the surface magnetic waveforms of the original magnetic ring and the two unequal thickness magnetic rings of the present invention, where the horizontal axis represents the angle of the magnetic ring 0-360°, and the vertical axis represents the value of the surface radial magnetic flux density. It can be seen that the surface magnetic waveform of the unequal thickness magnetic ring of the present invention is closer to a sine wave, which means that its high-order harmonic content is lower than that of ordinary magnetic rings. Fig. 9 Shown Figure 1 The harmonic decomposition result of the waveform, where the horizontal axis represents the order of the harmonic and the vertical axis represents the amplitude of the harmonic of that order. Fig. 9 In the harmonic order, black represents ordinary magnetic rings. Ordinary magnetic rings have higher amplitudes in odd harmonic positions such as 3, 5, and 7. After unequal thickness optimization, Fig. 9 As shown in the blue and red cases, the third-order harmonic has been significantly reduced compared to the black case, and the odd-order harmonics such as 5 and 7 have also been reduced. It is worth noting that according to the first optimization function, the high-order harmonics of the unequal thickness magnetic ring 1 are most significantly reduced, and according to the second optimization function, the high-order harmonics of the unequal thickness magnetic ring 2 are slightly higher than the first one, but are significantly lower than the ordinary magnetic ring, and the fundamental amplitude of the unequal thickness magnetic ring 2 is higher than that of the unequal thickness magnetic ring 1.

[0076] Example 3

[0077] A functionalized outer diameter and unequal thickness magnetic ring, as described in Example 1 or 2, except that, during the production, the raw materials are first melted at high temperature by casting or smelting to form an alloy; the raw materials are selected from high-purity neodymium iron boron and other elements, and a small amount of other elements (such as dysprosium, cerium, etc.) are usually added to improve the magnetic properties. After the alloy is cooled, it is crushed and ground to form a nanometer-scale powder; the nanometer-scale powder is mixed with a binder (epoxy resin) to obtain a mixture; the mixture is molded by pressing or injection molding to form a blank of a desired shape; the molded blank is cured at a specific temperature to fully cross-link the binder and enhance the mechanical strength of the magnet, and then the final product is obtained by post-processing, surface treatment and other processes.

[0078] Example 4

[0079] A method for magnetizing a magnetic ring with a functional outer diameter and unequal thickness, using a magnetizing fixture to complete the magnetization, such as Figure 3 to Figure 5 As shown, the magnetizing fixture includes a base 5, a magnetizing core 3, a winding 4 and a positioning device 2, the winding 4 is made of enameled copper wire; the base 5 and the positioning device 2 are made of non-magnetic conductive materials;

[0080] During magnetization, the magnetic ring 1 is placed on the magnetizing core 3 and fixed with the positioning device 2. The two ends of the winding 4 are respectively connected to the positive and negative poles of the pulse power supply, and then power is turned on for magnetization. After power is turned off, the magnetic ring structure is taken out to complete the magnetization.

[0081] The base 5 is provided with a groove, in which the magnetized core 3 is placed, and a positioning column is provided at the center of the groove for positioning the magnetized core 3;

[0082] The magnetizing core 3 is provided with a through hole and a winding groove 32, and the winding groove 32 is used to install the winding; a groove opening 31 is provided between the winding groove 32 and the through hole, and a magnetizing position 33 is formed between adjacent groove openings 31; the positioning device 2 includes a disc and positioning plates 21 uniformly distributed around the disc, the disc is placed in the through hole on the magnetizing core, the positioning plate 21 is stuck in the groove opening 31, the groove opening 31 is consistent with the thickness of the positioning plate 21 in the magnetic ring positioning device, and the positioning plate 21 is stuck in the groove opening for positioning, which is simple and convenient; the magnetic ring 1 is sleeved in the positioning device 2, wherein the positioning plate corresponds to the transition position of the magnetic ring, which plays a role in limiting the circumferential rotation of the magnetic ring. During assembly, the six positioning plates 21 are respectively positioned in the six groove openings 31, at which time the transition position 12 of the magnetic ring is just limited by the positioning plate, aligned with the groove opening, and the main magnetic pole part 11 of the magnetic ring is aligned with the magnetizing position 33.

[0083] The number of positioning plates is 6.

[0084] The positioning device can be fixed together with the magnetized core by using adhesive, and mass magnetization can be performed by simply replacing the magnetic ring.

[0085] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A functionalized outer diameter and unequal thickness magnetic ring, characterized in that: The inner diameter of the unequal thickness magnetic ring is a circle, and the outer diameter is a changing curve, wherein the thickness of the changing curve of the outer diameter remains unchanged in the main magnetic pole part, and the thickness decreases at the transition position between adjacent main magnetic pole parts; The unequal thickness magnetic rings are made of bonded NdFeB material.

2. The functionalized outer diameter and unequal thickness magnetic ring according to claim 1, characterized in that: The outer diameter of the unequal thickness magnetic ring satisfies: R0=(R1-H)+H×cos(nθ) Among them, R0 is the outer diameter of the optimized magnetic ring; R1 is the outer diameter of the original magnetic ring; H is the pole cutting parameter, which satisfies: R1-2H>R2, R2 is the inner diameter of the magnetic ring; n is the number of magnetic poles; θ represents the circular angle, 0°<θ<360°.

3. The functionalized outer diameter and unequal thickness magnetic ring according to claim 1, characterized in that: The outer diameter of the unequal thickness magnetic ring satisfies: Among them, R0 is the outer diameter of the optimized magnetic ring; R1 is the outer diameter of the original magnetic ring; H is the pole cutting parameter, which satisfies: R1-2H>R2, R2 is the inner diameter of the magnetic ring; n is the number of magnetic poles; θ represents the circular angle, 0°<θ<360°.

4. The functionalized outer diameter unequal thickness magnetic ring according to claim 2 or 3, characterized in that: When determining the pole cutting parameter H, according to the restriction of R1-2H>R2, in the finite element simulation, the value range of H is set to Set the value step size according to the solution requirements, solve all possible H values, and select the H value with the lowest surface magnetic harmonic distortion rate as the final result.

5. The functionalized outer diameter and unequal thickness magnetic ring according to claim 4, characterized in that: During the production, the raw materials are first melted at high temperature by casting or smelting to form an alloy; after the alloy is cooled, it is crushed and ground to form a nanometer-scale powder; the nanometer-scale powder is mixed with a binder to obtain a mixture; the mixture is molded by a pressing or injection molding process to form a blank of a desired shape; the molded blank is solidified to fully cross-link the binder and enhance the mechanical strength of the magnet, and the final product is obtained after post-processing and surface treatment.

6. The functionalized outer diameter and unequal thickness magnetic ring according to claim 5, characterized in that: The adhesive is epoxy resin or polyurethane.

7. A magnetizing method for a functionalized magnetic ring with unequal outer diameter and thickness according to claim 2, characterized in that: The magnetization is completed with the help of a magnetization fixture, which includes a base, a magnetization core, a winding and a positioning device. The winding adopts enameled copper wire; the base and the positioning device adopt non-magnetic conductive materials; During magnetization, place the magnetic ring on the magnetizing core and fix it with a positioning device. Connect the two ends of the winding to the positive and negative poles of the pulse power supply respectively, and then power on for magnetization. After power off, take out the magnetic ring structure to complete the magnetization.

8. A magnetizing method for a functionalized magnetic ring with unequal outer diameter and thickness as claimed in claim 7, characterized in that: The base is provided with a groove, in which the magnet-filled core is placed, and a positioning column is provided at the center of the groove for positioning the magnet-filled core; The magnetized core is provided with a through hole and a winding groove, and the winding groove is used to install the winding; a groove opening is provided between the winding groove and the through hole, and a magnetization position is formed between adjacent groove openings; the positioning device includes a disc and positioning plates evenly distributed around the disc, the disc is placed in the through hole on the magnetized core, and the positioning plates are stuck in the groove openings; the magnetic ring is sleeved in the positioning device, wherein the positioning plate corresponds to the transition position of the magnetic ring, and plays a role in limiting the circumferential rotation of the magnetic ring.

9. A magnetizing method for a functionalized magnetic ring with unequal outer diameter and thickness as claimed in claim 8, characterized in that: The number of positioning plates is the same as the number of magnetic poles.

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