Magnetic ring preparation method and device

Abstract

The invention provides a magnetic ring preparation method and device. The method comprises the following steps: obtaining cubic or spherical sample magnetic powder; the particle size distribution value of the sample magnetic powder meets a first threshold value; a finite element simulation mechanism is utilized to adjust the magnetic pole shape and position distribution of the prefabricated magnetic ring, and a target magnetic field direction meeting multi-pole normal distribution is obtained; based on the target magnetic field direction and oil pump parameters, bidirectionally pressing the sample magnetic powder to form a magnetic ring green body; oil pump parameters are used for adjusting pressing or powder adding pressure; the two directions are pressing directions of the upper side and the lower side of the prefabricated magnetic ring; and performing multi-gradient sintering heat treatment on the magnetic ring green body to obtain the target magnetic ring. In conclusion, according to the technical scheme provided by the invention, the magnetic field waveform sine degree of the magnetic field finished product can be improved, the total harmonic distortion is reduced, the accuracy is improved, and the method can adapt to various application scenes.

Description

A method and apparatus for preparing a magnetic ring Technical Field

[0001] This disclosure relates to the field of rare earth permanent magnet materials and magnetic rings, and in particular to a method and apparatus for preparing magnetic rings. Background Technology

[0002] Currently, existing methods for manufacturing magnetic rings often use irregularly shaped magnetic powder raw materials without strict control over the particle size distribution. The molding stage relies heavily on unidirectional pressing or simple multidirectional pressing processes, and the orientation magnetic field parameters are mostly set empirically, making it difficult to achieve high-precision and flexible control. These factors result in poor sinusoidal magnetic field waveforms, significant total harmonic distortion, and reduced accuracy in the finished magnetic rings, making them unsuitable for various application scenarios. Summary of the Invention

[0003] This disclosure provides a method and apparatus for preparing magnetic rings, which addresses, to some extent, the problems encountered in existing magnetic ring preparation methods. These methods often employ irregularly shaped magnetic powder raw materials, lack strict control over the particle size distribution of the powder, rely heavily on unidirectional pressing or simple multidirectional pressing processes during the molding stage, and use oriented magnetic field parameters based on empirical settings, making it difficult to achieve high-precision and flexible control. These factors result in poor sinusoidal magnetic field waveforms, significant total harmonic distortion, reduced accuracy, and difficulty in adapting to various application scenarios for the finished magnetic rings.

[0004] According to one aspect of this disclosure, a method for preparing a magnetic ring is provided, the method comprising: obtaining cubic or spherical sample magnetic powder; the particle size distribution value of the sample magnetic powder satisfies a first threshold; using a finite element simulation mechanism, adjusting the magnetic pole shape and position distribution of the pre-prepared magnetic ring to obtain a target magnetic field direction that satisfies a multi-pole normal distribution; based on the target magnetic field direction and oil pump parameters, bidirectionally pressing the sample magnetic powder to form a magnetic ring green blank; the oil pump parameters are used to adjust the pressing or powder adding pressure; bidirectional refers to the upper and lower pressing directions of the pre-prepared magnetic ring; and performing multi-gradient sintering heat treatment on the magnetic ring green blank to obtain the target magnetic ring.

[0005] Furthermore, according to one aspect of the method of this disclosure, the method further includes: obtaining a green magnetic ring based on the target magnetic field direction and applied external magnetic field parameters.

[0006] Furthermore, according to one aspect of the method of this disclosure, obtaining cubic or spherical sample magnetic powder includes: grinding the magnetic powder raw material using an airflow or ball milling device; screening the ground magnetic powder raw material by shape and particle size, and determining the magnetic powder raw material with a cubic or spherical shape and a particle size that meets a first threshold as sample magnetic powder.

[0007] Furthermore, according to one aspect of the method disclosed herein, the magnetic pole shape and position distribution of a pre-prepared magnetic ring are adjusted using a finite element simulation mechanism to obtain a target magnetic field direction that satisfies a multi-pole normal distribution. This includes: using finite element simulation software to obtain an orientation magnetic field simulation model, and adjusting the magnetic pole shape and position distribution in the orientation magnetic field simulation model to obtain multiple candidate magnetic field directions; the magnetic pole shape includes at least: fan-shaped, trapezoidal, and arc-shaped; the position distribution includes: uniform distribution at equal angles; when a candidate magnetic field direction satisfies the distribution state of maximum intensity in the central region of the magnetic pole and symmetrical intensity between the two poles, it is determined as the target magnetic field direction.

[0008] Furthermore, according to one aspect of the method disclosed herein, the oil pump parameters include: oil pump rapid downpressure, oil pump pressing pressure, and oil pump powder adding pressure.

[0009] Furthermore, according to one aspect of the method disclosed herein, a magnetic ring green body is formed by bidirectionally pressing sample magnetic powder based on the target magnetic field direction and oil pump parameters, comprising: starting the oil pump and adding sample magnetic powder into the cavity of a magnetic ring mold based on a preset oil pump powder adding pressure; driving the upper and lower pressure heads to synchronously and rapidly descend to the surface of the sample magnetic powder based on a preset oil pump rapid descending pressure; and adjusting the pressure and position of the upper and lower pressure heads based on the preset oil pump pressing pressure and the target magnetic field direction to bidirectionally pressurize the sample magnetic powder in the cavity to obtain a magnetic ring green body.

[0010] Furthermore, according to one aspect of the method of this disclosure, the parameters for applying the external magnetic field include: magnetic field strength and the timing of magnetic field application or removal.

[0011] Furthermore, according to one aspect of the method of this disclosure, a magnetic ring green blank is obtained based on the target magnetic field direction and the applied external magnetic field parameters, including: obtaining a preset magnetic field strength and magnetic field application or removal sequence; starting a magnetic field generating device and applying an external magnetic field to the sample magnetic powder along the target magnetic field direction based on the preset magnetic field strength; and pressurizing the external magnetic field according to the preset magnetic field application or removal sequence until the magnetic field removal sequence is met, thereby obtaining a magnetic ring green blank.

[0012] Furthermore, according to one aspect of the method disclosed herein, a target magnetic ring is obtained by performing multi-gradient sintering heat treatment on a magnetic ring green blank, comprising: configuring multi-gradient sintering parameters; the multi-gradient sintering parameters being at least three gradients; the sintering parameters including at least one of the following: sintering temperature and sintering time; performing a low-temperature debinding treatment on the magnetic ring green blank based on a first gradient sintering parameter; performing a heated sintering treatment on the debinding magnetic ring green blank based on a second gradient sintering parameter; and performing a cooling treatment on the sintered magnetic ring green blank based on a third gradient sintering parameter to obtain the target magnetic ring.

[0013] According to another aspect of this disclosure, a magnetic ring preparation apparatus is provided, comprising: an acquisition unit for acquiring cubic or spherical sample magnetic powder; the particle size distribution value of the sample magnetic powder satisfies a first threshold; an adjustment unit for adjusting the magnetic pole shape and position distribution of the pre-prepared magnetic ring using a finite element simulation mechanism to obtain a target magnetic field direction that satisfies a multi-pole normal distribution; a pressing unit for bidirectionally pressing the sample magnetic powder to form a magnetic ring green blank based on the target magnetic field direction and oil pump parameters; the oil pump parameters are used to adjust the pressing or powder adding pressure; bidirectional refers to the upper and lower pressing directions of the pre-prepared magnetic ring; and a sintering unit for performing multi-gradient sintering heat treatment on the magnetic ring green blank to obtain the target magnetic ring.

[0014] This disclosure provides a method and apparatus for preparing a magnetic ring. The method involves obtaining cubic or spherical sample magnetic powder; ensuring the particle size distribution of the sample magnetic powder meets a first threshold; using a finite element simulation mechanism, adjusting the shape and position distribution of the magnetic poles of the pre-prepared magnetic ring to obtain a target magnetic field direction that satisfies a multi-pole normal distribution; based on the target magnetic field direction and oil pump parameters, bidirectionally pressing the sample magnetic powder to form a magnetic ring green body; the oil pump parameters are used to adjust the pressing or powder addition pressure; bidirectional refers to the upper and lower pressing directions of the pre-prepared magnetic ring; and multi-gradient sintering heat treatment is performed on the magnetic ring green body to obtain the target magnetic ring. Compared to existing magnetic ring preparation processes, this disclosure improves filling uniformity through regularized magnetic powder morphology and a strict particle size threshold; achieves high-precision and flexible control of the orientation magnetic field by replacing empirical parameter settings with finite element simulation; improves the defects of uneven green body density and orientation through bidirectional pressing and dynamic pressure adjustment mechanisms; and optimizes the sintering state of the magnetic ring by combining multi-gradient sintering heat treatment. In summary, the technical solution provided in this disclosure can improve the sinusoidal nature of the magnetic field waveform of the finished magnetic field product, reduce total harmonic distortion, improve accuracy, and adapt to various application scenarios.

[0015] It should be understood that both the foregoing general description and the following detailed description are exemplary and intended to provide further illustration of the claimed technology. Attached Figure Description

[0016] The above and other objects, features, and advantages of this disclosure will become more apparent from the more detailed description of the embodiments thereof in conjunction with the accompanying drawings. The drawings are provided to further illustrate the embodiments of this disclosure and form part of the specification. They are used together with the embodiments of this disclosure to explain the disclosure and do not constitute a limitation thereof. In the drawings, the same reference numerals generally represent the same components or steps.

[0017] Figure 1 is a schematic flowchart of a magnetic ring preparation method provided in an embodiment of this disclosure;

[0018] Figure 2 is a schematic diagram of the simulated target magnetic field direction provided in the embodiments of this disclosure;

[0019] Figure 3 is a structural block diagram of a magnetic ring preparation apparatus provided in an embodiment of this disclosure. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this disclosure more apparent, exemplary embodiments according to this disclosure will now be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this disclosure, and not all embodiments of this disclosure. It should be understood that this disclosure is not limited to the exemplary embodiments described herein.

[0021] Currently, existing methods for manufacturing magnetic rings often use irregularly shaped magnetic powder raw materials without strict control over the particle size distribution. The molding stage relies heavily on unidirectional pressing or simple multidirectional pressing processes, and the orientation magnetic field parameters are mostly set empirically, making it difficult to achieve high-precision and flexible control. These factors result in poor sinusoidal magnetic field waveforms, significant total harmonic distortion, and reduced accuracy in the finished magnetic rings, making them unsuitable for various application scenarios.

[0022] Therefore, to address the aforementioned problems, this disclosure provides a method for preparing magnetic rings. This method improves filling uniformity by regulating the morphology of the magnetic powder and setting strict particle size thresholds; it achieves high-precision and flexible control of the orientation magnetic field by replacing empirical parameter settings with finite element simulation; it improves the defects of uneven green density and orientation through bidirectional pressing and dynamic pressure adjustment mechanisms; and it optimizes the sintering state of the magnetic ring by combining multi-gradient sintering heat treatment. In summary, the technical solution provided by this disclosure can improve the sinusoidal nature of the magnetic field waveform of the finished magnetic field, reduce total harmonic distortion, and improve accuracy, making it suitable for various application scenarios.

[0023] This disclosure provides a method for preparing a magnetic ring. Please refer to Figure 1, which is a schematic flowchart of a method for preparing a magnetic ring according to an embodiment of this disclosure. As shown in Figure 1, the method includes:

[0024] In step S101, cubic or spherical sample magnetic powder is obtained; the particle size distribution value of the sample magnetic powder satisfies the first threshold.

[0025] In step S102, the magnetic pole shape and position distribution of the pre-prepared magnetic ring are adjusted using the finite element simulation mechanism to obtain the target magnetic field direction that satisfies the multipole normal distribution.

[0026] In step S103, based on the target magnetic field direction and oil pump parameters, the sample magnetic powder is bidirectionally pressed to form a magnetic ring green body; the oil pump parameters are used to adjust the pressing or powder adding pressure; bidirectional refers to the upper and lower pressing directions of the pre-prepared magnetic ring.

[0027] In step S104, the green magnetic ring is subjected to multi-gradient sintering heat treatment to obtain the target magnetic ring.

[0028] In this disclosure, the sample magnetic powder can be understood as sintered NdFeB powder, with a particle morphology close to cubes or spheres. Specific additives can be added in a certain proportion to reduce or eliminate static magnetic agglomeration forces between powder particles, making it a core raw material for preparing magnetic rings. The particle size distribution value of the sample magnetic powder can be understood as the proportion of sample magnetic powder of different particle sizes in the overall powder, reflecting the degree of concentration of magnetic powder particle size. The first threshold can be understood as a particle size distribution standard to ensure that the magnetic powder has excellent forming and orientation properties, and can be flexibly set.

[0029] In this disclosure, the finite element simulation mechanism can be understood as a computer-based numerical analysis technique. By constructing a three-dimensional model of the orientation magnetic field system, the shape and arrangement of the magnetic poles can be accurately calculated and simulated to optimize the results. This allows the determination of the optimal parameter combination that enables the formation of an ideal multi-pole normally distributed magnetic field in the mold cavity. This can replace the traditional empirical design method and improve the controllability and accuracy of the magnetic field distribution.

[0030] In this disclosure, the magnetic pole shape can be understood as the geometric contour of the magnetic pole head in an orientation magnetic field system, and its design rationality can determine the distribution pattern of the magnetic field within the mold cavity. The magnetic pole shapes disclosed in this disclosure include at least: fan-shaped, trapezoidal, and arc-shaped; specifically, the fan-shaped magnetic pole head is easy to process and suitable for scenarios with basic accuracy requirements; the trapezoidal magnetic pole head can optimize the transition effect of the magnetic field between poles and reduce abrupt changes in the magnetic field; the arc-shaped magnetic pole head, after optimization by finite element simulation, can make the magnetic field strength decay more smoothly from the center of the magnetic pole to the inter-pole region, adapting to the requirements of high-precision magnetic field distribution, and is the preferred magnetic pole shape type adopted in this disclosure.

[0031] In this disclosure, the positional distribution can be understood as the arrangement of multiple magnetic pole heads in the orientation magnetic field system along the corresponding circumferential direction of the mold cavity. The positional distribution of this disclosure includes: uniform distribution at equal angles; specifically, uniform distribution at equal angles means that each magnetic pole head is arranged at the same central angle interval, suitable for the fabrication of conventional pole-pair magnetic rings. It should be noted that the positional distribution and magnetic shape design of this disclosure can be used in combination; that is, uniform distribution at equal angles combined with pole shoe design (fan-shaped, trapezoidal, arc-shaped, etc.) can further optimize the normal distribution effect of the magnetic field and effectively cancel higher harmonic components.

[0032] In this disclosure, the multipole normal distribution can be simply understood as the ideal distribution law of the magnetic field strength formed during the magnetic ring preparation stage. That is, the magnetic field strength is the largest in the central region of each target magnetic pole and decreases smoothly and symmetrically towards the interpole regions without obvious abrupt changes. The trajectory direction followed by the magnetic field strength during the smooth decrease from the magnetic pole center to the interpole region can be understood as the target magnetic field direction. This direction is the core benchmark to ensure the precise orientation of the magnetic powder particles.

[0033] In this disclosure, the oil pump parameters can be understood as a set of parameters controlling the operation of the oil pump during the bidirectional pressing process of magnetic powder to ensure the uniformity of the green blank. These parameters can be adjusted to achieve a highly uniform distribution of the green blank density in both the circumferential and axial directions. The oil pump parameters of this disclosure include: rapid downward pressure, pressing pressure, and powder feeding pressure. Specifically, the rapid downward pressure controls the pressure when the pressing punch rapidly descends to near the magnetic powder material. Combined with the rapid downward flow rate, it balances processing efficiency with the initial stability of the magnetic powder. The pressing pressure is the core pressure parameter in the forming stage. Combined with the pressing flow rate, it compacts the magnetic powder, ensuring sufficient density in the green blank. The powder feeding pressure, combined with the powder feeding flow rate, dynamically adjusts the powder feeding amount according to the magnetic powder filling amount in different areas of the mold, avoiding localized powder shortages or excessive accumulation.

[0034] In this disclosure, multi-gradient sintering treatment can be understood as a heat treatment method in which a magnetic ring green blank is placed in a sintering furnace and heated, held and cooled step by step according to multiple preset temperature stages (including multi-stage heat preservation, precise heating and cooling in the sintering process, and multi-stage aging in the tempering process). The purpose is to achieve degreasing and densification of the green blank, while controlling uniform grain growth and uniform distribution of grain boundary phases, and avoiding magnetic performance defects caused by a single temperature mode.

[0035] In this embodiment, the preparation of the magnetic ring includes the following steps: Step 1: Raw material powder preparation and screening; by optimizing the air jet mill process parameters and combining them with classification control technology, sintered NdFeB powder with particle morphology close to cubes or spheres is prepared. At the same time, a certain proportion of special additives are added to the powder to reduce or eliminate the static magnetic agglomeration force between powders. The prepared powder is tested with a laser particle size analyzer, and sample magnetic powder with particle size distribution meeting the first threshold is screened. Then, the screened sample magnetic powder is dried to remove surface moisture and impurities, ensuring that the magnetic powder has good flowability. Step 2: Orientation magnetic field parameter simulation optimization; a three-dimensional model of the orientation magnetic field system is constructed using the finite element simulation mechanism. The basic parameters such as the inner diameter, outer diameter, height, and target pole pairs of the pre-prepared magnetic ring are input, and the fan-shaped and trapezoidal magnetic field parameters are optimized. The simulation analysis was conducted on various magnetic pole shapes, including arc shapes, and positional distributions such as uniform distribution at equal angles and symmetrical distribution at non-uniform angles. Simultaneously, the excitation current parameters were precisely calculated to determine the optimal magnetic pole shape and arrangement, ultimately obtaining the target magnetic field direction that satisfies a multi-pole normal distribution. The third step involved bidirectional pressing to prepare the magnetic ring green blank. The pre-treated sample magnetic powder was loaded into a molding die with elastic deformation compensation design. Based on the target magnetic field direction obtained from the simulation, the orientation magnetic field system was activated. Simultaneously, the rapid downward pressure, pressing pressure, and powder feeding pressure of the oil pump were precisely set and adjusted. The punch was controlled to apply pressure bidirectionally and in multiple steps from the upper and lower sides of the magnetic ring, ultimately forming a magnetic ring green blank with a highly uniform orientation. The fourth step involved multi-gradient sintering heat treatment. Multi-stage heat preservation and precise heating / cooling rate control were implemented to obtain the target magnetic ring that met the requirements.

[0036] The following will elaborate on another method for greening magnetic rings, including:

[0037] Based on the target magnetic field direction and the applied external magnetic field parameters, a green magnetic ring is obtained.

[0038] In this disclosure, the applied external magnetic field parameters can be understood as the external magnetic field control parameters applied during the preparation of the magnetic ring green body to ensure the precise orientation of the magnetic powder particles. Precise control of these parameters can further improve the consistency of magnetic powder orientation and the potential of the green body's magnetic properties. The applied external magnetic field parameters in this disclosure include: magnetic field strength and the timing of magnetic field application or removal. Specifically, the magnetic field strength needs to match the magnetic field distribution requirements corresponding to the target magnetic field direction to ensure that the magnetic powder particles can be fully oriented along the target direction; the timing of magnetic field application or removal can be coordinated with molding steps such as magnetic powder filling and pressing to further ensure the uniformity of the green body's orientation.

[0039] In this embodiment, the following steps can be performed when obtaining the magnetic ring blank: Step 1: Sample magnetic powder pretreatment; using the same raw material preparation and screening process as described above, cubic or spherical sample magnetic powder that meets the first threshold is obtained; Step 2: Orientation magnetic field parameter determination; the shape and position distribution of magnetic poles are optimized through finite element simulation to obtain the target magnetic field direction that meets the multipole normal distribution; Step 3: External magnetic field parameter setting; the external magnetic field parameters can be set according to the target magnetic field direction and the size and pole pair requirements of the magnetic ring blank; Step 4: Magnetic powder filling and magnetic field application; the pretreated sample magnetic powder is uniformly loaded into the molding die. In the process, after the magnetic powder is filled in place, the external magnetic field generator is activated according to the set external magnetic field parameters to create a magnetic field environment in the mold cavity that conforms to the direction of the target magnetic field. The fifth step is pressing and molding. The pressing system is activated, and the magnetic powder in the mold is pressed using appropriate pressure parameters. During the pressing process, the external magnetic field is continuously applied to ensure that the magnetic powder particles are compacted under pressure and always oriented along the direction of the target magnetic field. The sixth step is magnetic field removal and demolding. After pressing, the pressure is maintained for a period of time, and then the external magnetic field is removed according to the set sequence. The molded magnetic ring blank is then taken out to obtain a magnetic ring blank with uniform orientation and qualified density.

[0040] The following will explain in detail how to obtain sample magnetic powder, including:

[0041] The magnetic powder raw material is ground using airflow or ball milling equipment;

[0042] The ground magnetic powder raw materials are screened by shape and particle size. The magnetic powder raw materials with cubic or spherical shape and particle size that meet the first threshold are determined as sample magnetic powder.

[0043] In this disclosure, air jet milling can be understood as a grinding process that uses high-speed airflow to drive magnetic powder raw material particles to collide and rub against each other, thereby achieving material refinement. By adjusting parameters such as airflow pressure, airflow speed, and grinding chamber structure, the morphology and particle size distribution of magnetic powder particles can be controlled to promote the formation of a regular morphology that is close to cubic or spherical.

[0044] In this disclosure, ball mill equipment can be understood as equipment that refines magnetic powder raw materials through the impact and grinding action of grinding media (such as steel balls or ceramic balls). Its core is to utilize the kinetic energy generated by the rotation of the media to break the raw material particles. Specifically, it can be a planetary ball mill, a drum ball mill, etc.

[0045] In this embodiment of the disclosure, the following steps can be performed when obtaining sample magnetic powder: Step 1: Pretreatment of magnetic powder raw materials; sintered NdFeB ingots are selected as raw materials. The ingots are first crushed to millimeter-level particles through coarse and medium crushing processes to remove the oxide layer and impurities on the surface of the raw materials, thereby obtaining magnetic powder raw materials to be ground; Step 2: Grinding treatment; air jet milling or ball milling equipment is selected according to production needs; Step 3: Shape and particle size screening; air jet classification screening equipment is used to perform preliminary classification of the ground magnetic powder to remove oversized and undersized particles, and then image recognition technology is used to screen out magnetic powder particles with cubic or spherical shapes; a laser particle size analyzer is used to detect the particle size of the screened magnetic powder, and magnetic powder with a particle size that meets the first threshold is selected; Step 4: Subsequent optimization treatment; special additives (such as zinc stearate, rare earth oxides, etc.) are added to the qualified magnetic powder, and the mixture is mixed evenly by a high-speed mixer to reduce or eliminate the static magnetic agglomeration force between powders, and finally obtain sample magnetic powder that meets the requirements.

[0046] The following will explain in detail how to obtain the direction of the target magnetic field, including:

[0047] Using finite element simulation software, a simulation model of the orientation magnetic field is obtained. The shape and position distribution of the magnetic poles are adjusted in the simulation model to obtain multiple candidate magnetic field directions. The magnetic pole shapes include at least: fan-shaped, trapezoidal, and arc-shaped. The position distribution includes: uniform distribution at equal angles and symmetrical distribution at non-equal angles.

[0048] When a candidate magnetic field direction satisfies the condition that the intensity is maximum in the central region of the magnetic poles and the intensity is symmetrical between the two poles, it is determined as the target magnetic field direction.

[0049] In this disclosure, finite element simulation software can be understood as computer-aided design software with electromagnetic numerical analysis capabilities, which can simulate the distribution of magnetic fields and optimize parameters by constructing a three-dimensional model, dividing into finite elements, and setting boundary conditions.

[0050] In this disclosure, the orientation magnetic field simulation model can be understood as a three-dimensional simulation model constructed based on the actual size of the pre-prepared magnetic ring and the structure of the orientation magnetic field system (including magnetic poles, mold cavity, etc.). The model includes parameters such as the shape and arrangement of the magnetic pole heads, and can accurately simulate the magnetic field distribution in the mold cavity under different parameter combinations.

[0051] In this disclosure, the candidate magnetic field direction can be understood as the various magnetic field distribution trajectory directions obtained in the orientation magnetic field simulation model by adjusting the magnetic pole shape (fan-shaped, trapezoidal, arc-shaped) and position distribution (uniform distribution at equal angles, symmetrical distribution at non-uniform angles). Each parameter combination corresponds to a candidate magnetic field direction, and the optimal direction can be determined by screening.

[0052] In this embodiment of the disclosure, the following steps can be performed to obtain the target magnetic field direction: Step 1: Simulation model construction; at least one finite element simulation software such as ANSYS Maxwell or COMSOL Multiphysics is selected, the collected basic parameters are imported, and an orientation magnetic field simulation model is constructed. The model includes structures such as magnetic poles, excitation coils, and mold cavities. Step 2: Generation of candidate magnetic field directions; in the simulation model, the magnetic pole shapes are set to fan-shaped, trapezoidal, and arc-shaped, and the position distribution is set to uniform distribution at equal angles and symmetrical distribution at non-uniform angles. At the same time, different excitation current parameters are matched, and the magnetic field distribution trajectory in the mold cavity under each parameter combination is obtained through simulation calculation, generating multiple candidate magnetic field directions. Step 3: Candidate magnetic field direction screening; the magnetic field distribution data corresponding to each candidate magnetic field direction is analyzed, the change of magnetic field strength between the magnetic pole center region and the inter-pole region is detected, and the candidate direction that satisfies the condition of maximum strength in the magnetic pole center region and symmetrical attenuation distribution between the two inter-pole regions is screened out and determined as the target magnetic field direction.

[0053] For example, Figure 2 is a schematic diagram of the simulated target magnetic field direction provided in the embodiments of this disclosure. As can be seen from Figure 2, the magnetic field trajectory exhibits a distribution state in which the magnetic field extends symmetrically in a vortex shape from the center of each magnetic pole towards the adjacent magnetic poles. That is, the magnetic field lines are dense and have the greatest intensity in the central region of the magnetic poles, while in the region between adjacent magnetic poles, the magnetic field lines diverge symmetrically from the center to both sides and the density decreases uniformly. The overall magnetic field distribution conforms to the target state of the magnetic pole center having the greatest intensity and the intensity between the two poles being symmetrical.

[0054] The following will explain in detail how to obtain the magnetic ring green blank, including:

[0055] Start the oil pump and, based on the preset oil pump powder feeding pressure, add the sample magnetic powder into the cavity of the magnetic ring mold;

[0056] Based on the preset oil pump rapid downward pressure, the upper and lower pressure heads are driven to descend synchronously and rapidly to the surface of the sample magnetic powder;

[0057] Based on the preset oil pump pressing pressure and target magnetic field direction, the pressure and position of the upper and lower pressure heads are adjusted to apply bidirectional pressure to the sample magnetic powder in the cavity, thereby obtaining a magnetic ring green blank.

[0058] In this disclosure, the oil pump can be understood as the power source equipment in the pressing and forming process of the magnetic ring green billet. Its core function is to convert mechanical energy into hydraulic energy through the hydraulic system, and to provide stable and precisely controllable pressure and flow output for actions such as adding magnetic powder, rapid pressing head, and bidirectional pressurization. It is a key device to ensure the uniformity of green billet density.

[0059] In this disclosure, the cavity of the magnetic ring mold can be understood as a hollow chamber structure in the magnetic ring mold that perfectly matches the shape and size of the pre-prepared magnetic ring product, and is the core area for sample magnetic powder filling and molding.

[0060] In this embodiment, the following steps can be performed when obtaining the magnetic ring blank: Step 1: The pre-treated sample magnetic powder (cubic / spherical shape, particle size meeting the first threshold, and with added anti-agglomeration additives) is loaded into the powder feeding mechanism. Simultaneously, based on the specifications of the pre-prepared magnetic ring (inner diameter, outer diameter, height), parameters such as the oil pump powder feeding pressure, oil pump fast-down pressure, and oil pump pressing pressure are preset, and the target magnetic field direction parameters obtained from finite element simulation are imported into the orientation magnetic field control system. Step 2: Precise magnetic powder filling; The oil pump is started, and according to the preset oil pump powder feeding pressure, the powder feeding mechanism is controlled to inject the sample magnetic powder into the cavity of the magnetic ring mold at a uniform speed. During the filling process, the filling status can be observed in real time through a visual monitoring module at the top of the mold cavity to avoid problems such as local accumulation, powder shortage, or porosity. Step 3: Rapid pressing head positioning; The oil pump is switched to the rapid-down working mode, which can... The first step involves a rapid, synchronized downward movement of the upper and lower pressure heads driven by a preset oil pump pressure until their lower surfaces are in contact with the sample magnetic powder. Strict control of the pressure head movement synchronicity is maintained throughout this rapid downward movement. The second step involves bidirectional pressurization. Based on the preset oil pump pressure, the pressure and position of the upper and lower pressure heads are dynamically adjusted to apply bidirectional pressure to the sample magnetic powder in the cavity. During pressurization, pressure and displacement sensors provide real-time data feedback to ensure that pressure deviation and displacement meet thresholds. The third step involves pressure holding and initial demolding. After the preset pressurization time is reached, the oil pump pressure is maintained for pressure holding to fully compact the magnetic powder particles. After pressure holding, the oil pump pressure is gradually reduced to a safe range, the orientation magnetic field system is shut off, and the molded magnetic ring preform is smoothly removed from the cavity via the mold's ejection mechanism, completing the preparation of the magnetic ring preform using the first method.

[0061] The following will elaborate on another method for obtaining a green magnetic ring, including:

[0062] Obtain the preset magnetic field strength and the timing of magnetic field application or removal;

[0063] Start the magnetic field generator and apply an external magnetic field to the sample magnetic powder along the target magnetic field direction based on the preset magnetic field strength;

[0064] The external magnetic field is pressurized according to the preset magnetic field application or removal sequence until the magnetic field removal sequence is met, thus obtaining a magnetic ring blank.

[0065] In this disclosure, the magnetic field generating device can be understood as a specialized electromagnetic device capable of generating a magnetic field that conforms to the target magnetic field direction and a preset magnetic field strength. Its core components typically include an excitation coil, a magnetic pole head, and a high-precision power control system. By adjusting the excitation current through the power control system, the output magnetic field strength can be precisely controlled. Optimizing the shape and arrangement of the magnetic pole head ensures that the magnetic field acts on the magnetic powder along the target direction, making it a core device for achieving precise magnetic powder orientation.

[0066] In this embodiment, the following steps can be performed when obtaining the magnetic ring blank: Step 1: Determine the target magnetic field direction through preliminary finite element simulation. Combined with parameters such as the number of pole pairs and dimensions of the pre-prepared magnetic ring, preset the magnetic field strength and magnetic field application / removal sequence. Load the pre-treated, qualified sample magnetic powder into the magnetic ring mold cavity and level it. Adjust the alignment accuracy between the magnetic field generating device and the mold to ensure that the magnetic field application direction is consistent with the target magnetic field direction. Simultaneously check the collaborative control module of the pressing system and the magnetic field generating device. Step 2: Start the magnetic field generating device and apply the external magnetic field. Turn on the high-precision power control system of the magnetic field generating device. Based on the preset magnetic field strength parameters, gradually adjust the excitation current to generate a stable external magnetic field. The external magnetic field acts precisely on the sample in the cavity along the target magnetic field direction. The process involves several steps: First, the magnetic powder is processed by a magnetic field strength sensor, which monitors the magnetic field inside the cavity in real time to ensure that the magnetic field strength deviation meets the threshold. Second, the pressing system is activated according to a preset sequence to pressurize the sample magnetic powder in the cavity. During the pressurization process, the magnetic field generator continuously maintains a stable output of the external magnetic field to ensure that the magnetic powder particles are compacted under pressure and always oriented along the target magnetic field direction, avoiding orientation deviation. Third, the magnetic field and pressure are removed according to a preset sequence. After the pressurization process is completed and the preset holding time is reached, the excitation current of the magnetic field generator is gradually reduced to zero according to the preset magnetic field removal sequence to complete the smooth removal of the external magnetic field. Then, the pressing pressure is gradually removed, and the molded magnetic ring blank is smoothly removed through the mold demolding mechanism to obtain a qualified magnetic ring blank.

[0067] The following will explain in detail how to perform multi-gradient sintering, including:

[0068] Configure multi-gradient sintering parameters; the multi-gradient refers to at least three gradients; the sintering parameters include at least one of the following: sintering temperature and sintering time;

[0069] Based on the first gradient sintering parameters, the magnetic ring green body is subjected to low-temperature debinding treatment.

[0070] Based on the second gradient sintering parameters, the magnetic ring green blank after debinding is subjected to heating sintering treatment.

[0071] Based on the third gradient sintering parameters, the sintered magnetic ring green blank is cooled to obtain the target magnetic ring.

[0072] In this disclosure, multi-gradient sintering parameters can be understood as a set of process parameters corresponding to at least three different stages divided according to the sintering process, in order to optimize the magnetic properties of the green ring after debinding. By precisely controlling the parameters in stages, problems such as abnormal grain growth and uneven distribution of grain boundary phases caused by a single parameter mode can be avoided. The sintering parameters of this disclosure include at least one of the following: sintering temperature and sintering time. Among them, sintering temperature refers to the set temperature in the sintering furnace in each gradient stage, which can determine the grain growth, grain boundary phase precipitation and densification degree inside the magnetic ring; sintering time refers to the duration of maintaining the corresponding sintering temperature in each gradient stage, which is used to ensure the full realization of the core objectives of this stage (such as debinding and uniform grain growth). The two need to be matched in a coordinated manner to ensure the magnetic properties and structural stability of the target magnetic ring.

[0073] In this disclosure, the low-temperature debinding process can be understood as the core operation of the first stage of multi-gradient sintering. Its main purpose is to fully decompose and remove impurities such as binder, additive residues and adsorbed moisture contained in the magnetic ring green body at a lower temperature, while avoiding cracking or deformation of the green body due to a sudden increase in temperature, thus laying a clean green body foundation for the subsequent high-temperature sintering densification process.

[0074] In this disclosure, the temperature-raising sintering process can be understood as the core stage of multi-gradient sintering. By gradually increasing the temperature and maintaining it for a specific time, the magnetic powder particles in the green magnetic ring undergo atomic diffusion and particle fusion, thereby achieving densification of the green body. This is the step that determines the density and basic magnetic properties of the target magnetic ring.

[0075] In this disclosure, the cooling process can be understood as the final stage of multi-gradient sintering. By precisely controlling the cooling rate in stages, the magnetic ring after high-temperature sintering is prevented from cracking due to internal stress caused by excessively rapid cooling. At the same time, suitable thermodynamic conditions are provided for the uniform precipitation and distribution of grain boundary phases, further optimizing the uniformity of magnetic properties of the magnetic ring, and finally obtaining a target magnetic ring with stable structure and excellent performance.

[0076] In this embodiment, the following steps can be performed during multi-gradient sintering: Step 1: Configure multi-gradient sintering parameters, setting at least three gradients; Step 2: Low-temperature debinding treatment; Start the sintering furnace and operate according to the first gradient sintering parameters, slowly raising the furnace temperature to a preset temperature and maintaining it for a preset time interval. During this process, the furnace gas circulation and exhaust system are activated to promptly remove binders, moisture, and other impurities discharged from the green body, ensuring the cleanliness of the green body; Step 3: Heating sintering treatment; After the debinding treatment is completed, sinter according to the second gradient. The parameters are used for heating and sintering. First, the temperature is rapidly increased to the preset temperature and held to provide conditions for the initial growth of grains. Then, the temperature is slowly increased to the final sintering temperature and held for a long time to promote the diffusion and fusion of magnetic powder particles and the densification of the green body. At the same time, it inhibits the abnormal growth of individual grains and ensures that the grain size is uniform. The fourth step is cooling treatment. After the heating and sintering is completed, the cooling operation is performed according to the third gradient sintering parameters. The temperature is slowly reduced in stages and held for specific purposes to avoid internal stress in the magnetic ring. After the temperature inside the furnace drops to room temperature, the sintering furnace can be opened and the qualified magnetic ring can be taken out, which is the target magnetic ring.

[0077] For example, this disclosure also provides a complete experimental process for the fabrication of a magnetic ring, including:

[0078] Step 1: Neodymium iron boron powder was obtained by hydrogen-airflow milling, with a D50 of 3.5 μm. Electron microscopy showed that the particles were close to cubic.

[0079] Step 2: Forming is performed using a bidirectional, multi-step pressurization process within a finite element-optimized hexapole orientation magnetic field, with an orientation magnetic field strength of 1.8–2.5 T. The measured density uniformity of the green body is 99.7%.

[0080] Step 3: In a vacuum sintering furnace, the temperature is increased to 1020℃ at 5℃ / min and held for 2 hours, then increased to 1060℃ at 1℃ / min and sintered for 3 hours. Subsequently, a first-stage tempering (920℃, 2 hours) and a second-stage tempering (500℃, 2 hours) are performed, both cooled by rapid argon gas cooling.

[0081] Step 4: Perform a circumferential magnetic field scan on the magnetized magnetic ring and calculate its total harmonic distortion value as 1.48%.

[0082] Step 5: Using ordinary NdFeB powder, conventional pulsed orientation magnetic field, single (bidirectional) pressing, and standard sintering and tempering process. The final total harmonic distortion (THD) value of the magnetic ring was measured to be within the range of 5% to 10%. A comparison of the embodiments described in steps 1 to 4 with this conventional method shows that the comprehensive improvement method provided in this disclosure can significantly reduce the THD value of the circumferential magnetic field of multipole magnetic rings, with effects far exceeding those of conventional processes.

[0083] This disclosure also provides a magnetic ring manufacturing apparatus. Figure 3 is a structural block diagram of a magnetic ring manufacturing apparatus provided in an embodiment of this disclosure. As shown in Figure 3, the magnetic ring manufacturing apparatus 300 includes:

[0084] The acquisition unit 301 is used to acquire cubic or spherical sample magnetic powder; the particle size distribution value of the sample magnetic powder satisfies a first threshold.

[0085] Adjustment unit 302 is used to adjust the shape and position distribution of the magnetic poles of the pre-prepared magnetic ring using the finite element simulation mechanism to obtain the target magnetic field direction that satisfies the multipole normal distribution;

[0086] The pressing unit 303 is used to bidirectionally press sample magnetic powder to form a magnetic ring preform based on the target magnetic field direction and oil pump parameters; the oil pump parameters are used to adjust the pressing or powder adding pressure; bidirectional refers to the upper and lower pressing directions of the pre-prepared magnetic ring.

[0087] The sintering unit 304 is used to perform multi-gradient sintering heat treatment on the green magnetic ring to obtain the target magnetic ring.

[0088] In one exemplary embodiment, the pressing unit 303 is further configured to: obtain a green magnetic ring based on the target magnetic field direction and the applied external magnetic field parameters.

[0089] In one exemplary embodiment, the acquisition unit 301 is specifically used to: grind the magnetic powder raw material using airflow or ball milling equipment; screen the ground magnetic powder raw material by shape and particle size, and determine the magnetic powder raw material with a cubic or spherical shape and a particle size that meets the first threshold as sample magnetic powder.

[0090] In one exemplary embodiment, the adjustment unit 302 is specifically used to: obtain an orientation magnetic field simulation model using finite element simulation software, and adjust the shape and position distribution of magnetic poles in the orientation magnetic field simulation model to obtain multiple candidate magnetic field directions; the magnetic pole shapes include at least: fan-shaped, trapezoidal, and arc-shaped; the position distribution includes: uniform distribution at equal angles; when the candidate magnetic field direction satisfies the distribution state of maximum intensity in the central region of the magnetic pole and symmetrical intensity between the two poles, it is determined as the target magnetic field direction.

[0091] In one exemplary embodiment, the pressing unit 303 is specifically used for: oil pump parameters including: oil pump rapid downpressure, oil pump pressing pressure, and oil pump powder adding pressure.

[0092] In one exemplary embodiment, the pressing unit 303 is specifically used to: start the oil pump and add sample magnetic powder into the cavity of the magnetic ring mold based on the preset oil pump powder adding pressure; drive the upper and lower pressing heads to synchronously and rapidly descend to the surface of the sample magnetic powder based on the preset oil pump fast downward pressure; and adjust the pressure and position of the upper and lower pressing heads based on the preset oil pump pressing pressure and the target magnetic field direction to apply bidirectional pressure to the sample magnetic powder in the cavity to obtain a magnetic ring blank.

[0093] In one exemplary embodiment, the suppression unit 303 is specifically used to: apply external magnetic field parameters including: magnetic field strength and the timing of magnetic field application or removal.

[0094] In one exemplary embodiment, the pressing unit 303 is specifically used to: obtain a preset magnetic field strength and magnetic field application or removal sequence; start the magnetic field generating device and apply an external magnetic field to the sample magnetic powder along the target magnetic field direction based on the preset magnetic field strength; pressurize the external magnetic field according to the preset magnetic field application or removal sequence until the magnetic field removal sequence is met, and obtain a magnetic ring blank.

[0095] In one exemplary embodiment, the sintering unit 304 is specifically used to: configure multi-gradient sintering parameters; the multi-gradient refers to at least three gradients; the sintering parameters include at least one of the following: sintering temperature and sintering time; perform low-temperature debinding treatment on the magnetic ring green blank based on the first gradient sintering parameters; perform heated sintering treatment on the magnetic ring green blank after debinding treatment based on the second gradient sintering parameters; and perform cooling treatment on the sintered magnetic ring green blank based on the third gradient sintering parameters to obtain the target magnetic ring.

[0096] In summary, this disclosure provides a method and apparatus for preparing magnetic rings. This disclosure involves obtaining cubic or spherical sample magnetic powder; ensuring the particle size distribution of the sample magnetic powder meets a first threshold; using a finite element simulation mechanism to adjust the shape and position distribution of the magnetic poles of the pre-prepared magnetic ring to obtain a target magnetic field direction that satisfies a multi-pole normal distribution; based on the target magnetic field direction and oil pump parameters, bidirectionally pressing the sample magnetic powder to form a magnetic ring green body; the oil pump parameters are used to adjust the pressing or powder addition pressure; bidirectional refers to the upper and lower pressing directions of the pre-prepared magnetic ring; and multi-gradient sintering heat treatment is performed on the magnetic ring green body to obtain the target magnetic ring. Thus, compared to existing magnetic ring preparation processes, this disclosure can improve filling uniformity by regularizing the magnetic powder morphology and strictly controlling the particle size threshold; achieve high-precision and flexible control of the orientation magnetic field by replacing empirical parameter settings with finite element simulation; improve the defects of uneven green body density and orientation degree through bidirectional pressing and dynamic pressure adjustment mechanisms; and optimize the sintering state of the magnetic ring by combining multi-gradient sintering heat treatment. In summary, the technical solution provided in this disclosure can improve the sinusoidal nature of the magnetic field waveform of the finished magnetic field product, reduce total harmonic distortion, improve accuracy, and adapt to various application scenarios.

[0097] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this disclosure.

[0098] The basic principles of this disclosure have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this disclosure are merely examples and not limitations, and should not be considered as essential features of each embodiment of this disclosure. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the scope of this disclosure to the necessity of employing the aforementioned specific details for implementation.

[0099] The block diagrams of devices, apparatuses, devices, and systems disclosed herein are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0100] Additionally, as used herein, the “or” used in a list of items beginning with “at least one” indicates a separate list, such that a list of, for example, “at least one of A, B, or C” means A or B or C, or AB or AC or BC, or ABC (i.e., A and B and C). Furthermore, the word “exemplary” does not imply that the described example is preferred or better than other examples.

[0101] It should also be noted that in the systems and methods of this disclosure, the components or steps can be decomposed and / or recombined. These decompositions and / or recombinations should be considered as equivalent solutions to this disclosure.

[0102] Various changes, substitutions, and modifications can be made to the technology described herein without departing from the teachings defined by the appended claims. Furthermore, the scope of the claims of this disclosure is not limited to the specific aspects of the processes, machines, manufactures, events, means, methods, and actions described above. Currently existing or later-developed processes, machines, manufactures, events, means, methods, or actions that perform substantially the same function or achieve substantially the same result as the corresponding aspects described herein can be utilized. Therefore, the appended claims include such processes, machines, manufactures, events, means, methods, or actions within their scope.

[0103] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this disclosure. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of this disclosure. Therefore, this disclosure is not intended to be limited to the aspects shown herein, but rather to be carried out within the widest scope consistent with the principles and novel features disclosed herein.

[0104] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this disclosure to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations therein.

Claims

1. A method for preparing a magnetic ring, characterized in that, The method includes: obtaining cubic or spherical sample magnetic powder; the particle size distribution of the sample magnetic powder satisfies a first threshold; using a finite element simulation mechanism, adjusting the magnetic pole shape and position distribution of a pre-prepared magnetic ring to obtain a target magnetic field direction that satisfies a multi-pole normal distribution; based on the target magnetic field direction and oil pump parameters, bidirectionally pressing the sample magnetic powder to form a magnetic ring green body; the oil pump parameters are used to adjust the pressing or powder adding pressure; the bidirectional pressing refers to the upper and lower pressing directions of the pre-prepared magnetic ring; and performing multi-gradient sintering heat treatment on the magnetic ring green body to obtain the target magnetic ring.

2. The method according to claim 1, characterized in that, The method further includes: obtaining the green magnetic ring based on the target magnetic field direction and the applied external magnetic field parameters.

3. The method according to claim 1, characterized in that, The process of obtaining cubic or spherical sample magnetic powder includes: grinding the magnetic powder raw material using an airflow or ball milling device; screening the ground magnetic powder raw material by shape and particle size, and determining the magnetic powder raw material whose shape is cubic or spherical and whose particle size meets the first threshold as the sample magnetic powder.

4. The method according to claim 1, characterized in that, The step of using finite element simulation to adjust the shape and position distribution of the magnetic poles of a pre-prepared magnetic ring to obtain a target magnetic field direction that satisfies a multi-pole normal distribution includes: using finite element simulation software to obtain an orientation magnetic field simulation model, and adjusting the shape and position distribution of the magnetic poles in the orientation magnetic field simulation model to obtain multiple candidate magnetic field directions; the shape of the magnetic poles includes at least: fan-shaped, trapezoidal, and arc-shaped; the position distribution includes: uniform distribution at equal angles; when the candidate magnetic field direction satisfies the distribution state of maximum intensity in the central region of the magnetic poles and symmetrical intensity between the two poles, it is determined as the target magnetic field direction.

5. The method according to claim 1, characterized in that, The oil pump parameters include: oil pump rapid descent pressure, oil pump pressing pressure, and oil pump powder adding pressure.

6. The method according to claim 1 or 5, characterized in that, The method of bidirectionally pressing the sample magnetic powder to form a magnetic ring preform based on the target magnetic field direction and oil pump parameters includes: starting the oil pump and adding the sample magnetic powder into the cavity of the magnetic ring mold based on a preset oil pump powder adding pressure; driving the upper and lower pressure heads to synchronously and rapidly descend to the surface of the sample magnetic powder based on a preset oil pump rapid descending pressure; and adjusting the pressure and position of the upper and lower pressure heads based on the preset oil pump pressing pressure and the target magnetic field direction to bidirectionally press the sample magnetic powder in the cavity to obtain the magnetic ring preform.

7. The method according to claim 2, characterized in that, The parameters for applying the external magnetic field include: magnetic field strength and the timing of applying or removing the magnetic field.

8. The method according to claim 2 or 7, characterized in that, The process of obtaining the magnetic ring blank based on the target magnetic field direction and applied external magnetic field parameters includes: acquiring a preset magnetic field strength and magnetic field application or removal sequence; activating a magnetic field generator to apply an external magnetic field to the sample magnetic powder along the target magnetic field direction based on the preset magnetic field strength; and applying pressure to the external magnetic field according to the preset magnetic field application or removal sequence until the magnetic field removal sequence is met, thereby obtaining the magnetic ring blank.

9. The method according to claim 1, characterized in that, The step of performing multi-gradient sintering heat treatment on the green magnetic ring to obtain the target magnetic ring includes: configuring multi-gradient sintering parameters; the multi-gradient refers to at least three gradients; the sintering parameters include at least one of the following: sintering temperature and sintering time; performing low-temperature debinding treatment on the green magnetic ring based on the first gradient sintering parameters; performing heated sintering treatment on the debinded green magnetic ring based on the second gradient sintering parameters; and performing cooling treatment on the sintered green magnetic ring based on the third gradient sintering parameters to obtain the target magnetic ring.

10. A magnetic ring manufacturing apparatus, characterized in that, The apparatus includes: an acquisition unit for acquiring cubic or spherical sample magnetic powder; the particle size distribution of the sample magnetic powder satisfies a first threshold; an adjustment unit for adjusting the magnetic pole shape and position distribution of a pre-prepared magnetic ring using a finite element simulation mechanism to obtain a target magnetic field direction that satisfies a multi-pole normal distribution; a pressing unit for bidirectionally pressing the sample magnetic powder to form a magnetic ring green body based on the target magnetic field direction and oil pump parameters; the oil pump parameters are used to adjust the pressing or powder adding pressure; the bidirectional pressing refers to the upper and lower pressing directions of the pre-prepared magnetic ring; and a sintering unit for performing multi-gradient sintering heat treatment on the magnetic ring green body to obtain the target magnetic ring.

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