Neodymium-iron-boron magnet grain boundary diffusion treatment system for new energy vehicle motor

Abstract

The application discloses a neodymium-iron-boron magnet grain boundary diffusion treatment system for a new energy automobile motor, which comprises a motor parameter acquisition module, a partition modeling module, a magnet posture positioning module, a diffusion source application module, a diffusion source state detection module, a closed-loop compensation control module, a partition thermal field grain boundary diffusion module, a post-diffusion detection grading module and a feedback correction module. The motor parameter acquisition module forms motor working condition data, the partition modeling module determines a demagnetization risk index of a surface of a magnet to be treated according to the motor working condition data, divides different diffusion regions and generates a diffusion execution parameter set. The diffusion source application module processes corresponding diffusion sources according to the diffusion execution parameter set and an actual surface, the closed-loop compensation control module generates a compensation instruction according to a diffusion source state evaluation value and the partition thermal field grain boundary diffusion module performs partition grain boundary diffusion heat treatment. The system can improve the coercive force of a high-risk area, reduce heavy rare earth consumption and improve batch consistency.

Description

Technical Field

[0001] This invention relates to the field of permanent magnet material manufacturing technology, and in particular to a grain boundary diffusion treatment system for neodymium iron boron magnets used in new energy vehicle motors. Background Technology

[0002] Sintered NdFeB magnets are widely used in drive motors for new energy vehicles due to their high remanence, magnetic energy product, and energy density. As new energy vehicle drive motors develop towards higher speeds, higher power densities, and miniaturization, they typically need to withstand significant current surges, wide field weakening speed ranges, and high operating temperatures during operation. Under these conditions, rotor magnets are susceptible to the combined effects of reverse demagnetizing fields, localized temperature rises, and differences in assembly positions, resulting in varying degrees of demagnetization risk.

[0003] In the drive motors of new energy vehicles, the actual service condition of neodymium iron boron magnets is not completely uniform. Due to differences in motor structure, magnet installation position, air gap distribution, heat conduction path, and operating conditions, different surface areas of the magnet experience varying demagnetization and thermal loads. Especially near the air gap, near the slot opening, at the corners, and in areas with higher local temperature rise, the magnet is more prone to local magnetic performance attenuation, which in turn affects the output stability and reliability of the drive motor.

[0004] To improve the demagnetization resistance of sintered NdFeB magnets, coercivity is typically enhanced through methods such as compositional control or grain boundary diffusion. Grain boundary diffusion treatment allows relevant diffusing elements to diffuse inwards along the magnet's grain boundaries, thereby improving the magnetic properties of the surface and near-surface regions. However, in actual batch processing, the demagnetization requirements, diffusion source distribution, and heat treatment conditions can vary across different regions of the magnet. If these differences are not effectively identified and controlled during the processing, some regions may experience insufficient strengthening, while others may suffer over-treatment.

[0005] Furthermore, the effectiveness of grain boundary diffusion treatment is closely related to the thickness, coverage, and edge coverage of the diffusion source layer, as well as the diffusion state during heat treatment. When the diffusion source layer is unevenly distributed or the heat input control is unstable, it can easily lead to inconsistent diffusion effects between different batches of magnets or different regions of the same magnet, thereby affecting the magnet's coercivity enhancement, remanence retention, and product consistency.

[0006] Meanwhile, the test results after diffusion treatment are usually used to evaluate the quality of finished magnets. However, in the process of mass production, when the correlation between the test results and subsequent process parameters is insufficient, it is easy for magnets under the same or similar service conditions to repeatedly exhibit similar quality fluctuations, which limits the stability and adaptability of the grain boundary diffusion treatment process.

[0007] Therefore, how to balance the anti-demagnetization requirements of different service areas, diffusion source utilization efficiency, heat treatment consistency, and batch process stability in the grain boundary diffusion treatment of NdFeB magnets has become a key technical issue that needs to be addressed in the manufacturing process of NdFeB magnets for drive motors of new energy vehicles. Summary of the Invention

[0008] To address the shortcomings of existing technologies, the present invention aims to provide a grain boundary diffusion treatment system for neodymium iron boron magnets used in new energy vehicle motors. This system is used to partition the surface of the magnet to be treated into demagnetization risk zones based on motor operating data, and to apply differentiated diffusion sources, partitioned grain boundary diffusion heat treatment, and closed-loop correction to different diffusion regions. This improves the demagnetization resistance of high demagnetization risk regions, reduces the consumption of heavy rare earth elements, and improves batch diffusion consistency.

[0009] To achieve the above objectives, the present invention provides the following technical solution: a grain boundary diffusion treatment system for neodymium iron boron magnets used in new energy vehicle motors, comprising: The motor parameter acquisition module is used to acquire the structural parameters, operating condition parameters and magnet assembly position parameters of the drive motor, and form motor operating condition data. The partition modeling module, connected to the motor parameter acquisition module, is used to determine the demagnetization risk index of each evaluation area on the surface of the magnet to be processed based on the motor operating data, and to divide the first diffusion area, the second diffusion area, and the third diffusion area according to the demagnetization risk index, and generate a diffusion execution parameter set. The magnet attitude localization module, connected to the partition modeling module, is used to identify the actual attitude of the magnet to be processed and map each diffusion region to the actual surface of the magnet to be processed. A diffusion source application module, connected to a partition modeling module and a magnet attitude positioning module, is used to perform corresponding diffusion source processing according to the diffusion execution parameter set and the actual surface to form a first diffusion source layer, a second diffusion source layer and a third diffusion source layer. The diffusion source status detection module is connected to the diffusion source application module and is used to detect the diffusion source layer thickness and coverage status of each diffusion region and generate diffusion source status evaluation values. A closed-loop compensation control module is connected to the diffusion source status detection module and is used to generate compensation instructions based on the diffusion source status evaluation value. The partitioned thermal field grain boundary diffusion module connects the partitioned modeling module, the diffusion source state detection module, and the closed-loop compensation control module. It is used to perform partitioned grain boundary diffusion heat treatment according to the diffusion execution parameter set, the diffusion source state evaluation value, and the compensation command to obtain the diffused magnet. The diffusion post-diffusion detection and grading module is connected to the partitioned thermal field grain boundary diffusion module and is used to detect the diffused magnet and determine the diffusion level. The feedback correction module, which connects the post-diffusion detection and grading module and the partition modeling module, is used to correct the diffusion execution parameter set for subsequent batches based on the diffusion level.

[0010] Furthermore, the partition modeling module includes: The evaluation area division unit is used to divide the surface of the magnet to be processed into multiple non-overlapping evaluation areas based on the motor operating data and the surface of the magnet to be processed. The risk parameter extraction unit, connected to the evaluation area division unit, is used to extract the corresponding temperature parameters, demagnetization field parameters, magnetization direction parameters, and boundary distance parameters based on the motor operating condition data and each of the evaluation areas. A demagnetization risk calculation unit, connected to the risk parameter extraction unit, is used to calculate the demagnetization risk index of each of the regions to be evaluated based on the temperature parameter, demagnetization field parameter, magnetization direction parameter, and boundary distance parameter. The partitioning determination unit, connected to the demagnetization risk calculation unit, is used to divide the corresponding area to be evaluated into a first diffusion area when the demagnetization risk index is greater than or equal to a first risk threshold, divide the corresponding area to be evaluated into a second diffusion area when the demagnetization risk index is less than the first risk threshold but greater than or equal to a second risk threshold, and divide the corresponding area to be evaluated into a third diffusion area when the demagnetization risk index is less than the second risk threshold. Wherein, the first risk threshold is greater than the second risk threshold.

[0011] Furthermore, the partition modeling module also includes: The parameter mapping unit, connected to the partition determination unit, is used to generate corresponding diffusion execution parameters according to the first diffusion region, the second diffusion region and the third diffusion region, respectively, to form the diffusion execution parameter set; The diffusion execution parameter set includes risk threshold parameters, diffusion source layer parameters, and heat treatment parameters. The risk threshold parameters include a first risk threshold and a second risk threshold. The diffusion source layer parameters include diffusion source layer structure, heavy rare earth reinforcement layer thickness parameters, and diffusion source application amount. The heat treatment parameters include target wetting evaluation threshold, zoned thermal input parameters, and compensation triggering conditions. The thickness parameter of the heavy rare earth reinforced layer corresponding to the first diffusion region is greater than that of the heavy rare earth reinforced layer corresponding to the second diffusion region, and the thickness parameter of the heavy rare earth reinforced layer corresponding to the third diffusion region is zero.

[0012] Furthermore, the magnet attitude positioning module includes: The attitude recognition unit is used to identify the end face, side face, corner, chamfer and air gap side surface of the magnet to be processed, and obtain magnet attitude data; An assembly direction recognition unit, connected to the attitude recognition unit, is used to determine the assembly direction of the magnet to be processed in the drive motor based on the motor operating condition data and the magnet attitude data. The partition mapping unit, connected to the assembly direction recognition unit, is used to map the first diffusion region, the second diffusion region, and the third diffusion region onto the actual surface of the magnet to be processed, based on the magnet attitude data, the assembly direction, and the first diffusion region, the second diffusion region, and the third diffusion region.

[0013] Furthermore, the diffusion source application module includes: A diffusion source selection unit is used to select the diffusion source layer type for the corresponding diffusion region according to the diffusion source layer parameters. A localized application unit, connected to the diffusion source selection unit, is used to apply a first diffusion source layer comprising a wetting promotion layer, a first heavy rare earth strengthening layer, and a diffusion adjustment layer to the first diffusion region, a second diffusion source layer comprising a wetting promotion layer and a second heavy rare earth strengthening layer to the second diffusion region, and a third diffusion source layer to the third diffusion region, based on the diffusion source layer type and the actual surface of the magnet to be processed; wherein, the heavy rare earth content parameter of the second heavy rare earth strengthening layer is less than the heavy rare earth content parameter of the first heavy rare earth strengthening layer, and the third diffusion source layer is a grain boundary modification layer without a heavy rare earth strengthening layer. A layer thickness control unit, connected to the localized application unit, is used to control the diffusion source layer thickness of each diffusion region according to the diffusion source application amount.

[0014] Furthermore, the diffusion source state detection module includes: The state acquisition unit is used to acquire the diffusion source layer thickness, coverage integrity, thickness uniformity and edge coverage of each diffusion region after the diffusion source is applied, and to acquire the melting and spreading degree of each diffusion region during the heating stage of the partition grain boundary diffusion heat treatment, so as to obtain diffusion source state data. The status evaluation unit, connected to the status acquisition unit, is used to generate a diffusion source status evaluation value for each diffusion region based on the diffusion source status data.

[0015] Furthermore, the closed-loop compensation control module is also connected to the diffusion source application module. The closed-loop compensation control module is used to control the diffusion source application module to perform recoating according to the recoating instruction, and to control the partitioned thermal field grain boundary diffusion module to perform heat treatment compensation according to the heat treatment compensation instruction. The closed-loop compensation control module includes: The threshold comparison unit is used to compare the diffusion source state evaluation value of each diffusion region with the corresponding target wetting evaluation threshold to obtain the state comparison result. The compensation instruction generation unit, connected to the threshold comparison unit, is used to generate the recoating instruction and / or the heat treatment compensation instruction when the state comparison result meets the corresponding compensation triggering condition. The heat treatment compensation instructions include one or more of the following: local heat replenishment instructions, heat preservation correction instructions, secondary grain boundary diffusion instructions, and cooling protection instructions.

[0016] Furthermore, the partitioned thermal field grain boundary diffusion module includes: An environmental control unit is used to provide a vacuum environment or a low-oxygen inert atmosphere environment for the magnet to be processed; The main heating unit is connected to the environmental control unit and is used to heat the magnet to be treated as a whole according to the heat treatment parameters. A partitioned heat input unit, connected to the main heating unit, is used to apply corresponding equivalent heat inputs to the first diffusion region, the second diffusion region, and the third diffusion region according to the partitioned heat input parameters and the heat treatment compensation instructions; wherein, the equivalent heat input corresponding to the first diffusion region is greater than the equivalent heat input corresponding to the second diffusion region, and the equivalent heat input corresponding to the second diffusion region is greater than or equal to the equivalent heat input corresponding to the third diffusion region; A cooling control unit, connected to the partitioned heat input unit, is used to cool the magnet after partitioned grain boundary diffusion heat treatment to obtain a diffused magnet.

[0017] Furthermore, the post-diffusion detection and grading module includes: The post-diffusion detection unit is used to perform magnetic flux detection, eddy current detection, surface composition detection, local magnetic property detection, and appearance inspection on the diffused magnet to obtain post-diffusion detection data. A grade determination unit, connected to the post-diffusion detection unit, is used to generate a diffusion quality evaluation value based on the post-diffusion detection data. When the diffusion quality evaluation value is greater than or equal to a first grade threshold, the diffused magnet is determined to be a first-grade magnet. When the diffusion quality evaluation value is less than the first grade threshold but greater than or equal to a second grade threshold, the diffused magnet is determined to be a second-grade magnet. When the diffusion quality evaluation value is less than the second grade threshold, the diffused magnet is determined to be a third-grade magnet. Wherein, the threshold of the first level is greater than the threshold of the second level.

[0018] Furthermore, the feedback correction module is also connected to the diffusion source application module and the partitioned thermal field grain boundary diffusion module, and the feedback correction module includes: The result association unit is used to associate the diffusion level with the motor operating data, the demagnetization risk index, the diffusion source layer parameters, and the heat treatment parameters to obtain batch association data. A parameter correction unit, connected to the result association unit, is used to generate feedback correction parameters based on the batch association data. The feedback correction parameters are used to correct one or more parameters in the diffusion execution parameter set of magnets to be processed in subsequent batches that have the same magnet assembly position parameters or motor condition data that meet preset working condition matching conditions. The one or more parameters in the diffusion execution parameter set include one or more of a first risk threshold, a second risk threshold, diffusion source layer parameters, and heat treatment parameters.

[0019] The beneficial effects of this invention are: First, the present invention determines the demagnetization risk index of each region on the surface of the magnet to be treated based on the motor operating data of the drive motor, and divides different diffusion regions accordingly, so that the grain boundary diffusion treatment matches the actual demagnetization risk of the magnet during service, which is beneficial to improve the demagnetization resistance of high demagnetization risk regions and reduce the over-treatment of low-risk regions.

[0020] Second, the present invention transforms the demagnetization risk partitioning results into the control basis for diffusion source treatment and partitioned grain boundary diffusion heat treatment by using a diffusion execution parameter set, so that different diffusion regions can form corresponding diffusion source layers and obtain corresponding heat treatment conditions, thereby improving the pertinence and feasibility of grain boundary diffusion treatment.

[0021] Third, the present invention generates a diffusion source state evaluation value through a diffusion source state detection module and generates a compensation command through a closed-loop compensation control module, which can correct the diffusion source layer thickness, coverage state and heat treatment process, thereby improving the consistency and stability of diffusion treatment.

[0022] Fourth, the present invention determines the diffusion level through a diffusion post-diffusion detection and grading module, and corrects the diffusion execution parameter set of subsequent batches by a feedback correction module, so that the diffusion process has batch feedback correction capability, which is beneficial to improving the production stability of neodymium iron boron magnets for new energy vehicle motors.

[0023] Fifth, this invention can improve the coercivity in high demagnetization risk areas while reducing the ineffective consumption of heavy rare earth elements and maintaining the remanence of the magnet, making it suitable for batch grain boundary diffusion treatment of neodymium iron boron magnets for new energy vehicle drive motors. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of the NdFeB magnet grain boundary diffusion treatment system for new energy vehicle motors in this invention; Figure 2 This is a schematic diagram of the partition modeling module in this invention; Figure 3 This is a schematic diagram of the magnet attitude positioning module in this invention; Figure 4This is a schematic diagram of the diffusion source application module in this invention; Figure 5 This is a schematic diagram of the diffusion source state detection module in this invention; Figure 6 This is a schematic diagram of the closed-loop compensation control module in this invention; Figure 7 This is a schematic diagram of the partitioned thermal field grain boundary diffusion module in this invention; Figure 8 This is a schematic diagram of the post-diffusion detection and grading module in this invention; Figure 9 This is a schematic diagram of the feedback correction module in this invention.

[0025] Figure reference numerals: 1. Motor parameter acquisition module; 2. Partition modeling module; 21. Region division unit to be evaluated; 22. Risk parameter extraction unit; 23. Demagnetization risk calculation unit; 24. Partition determination unit; 25. Parameter mapping unit; 3. Magnet attitude positioning module; 31. Attitude recognition unit; 32. Assembly direction recognition unit; 33. Partition mapping unit; 4. Diffusion source application module; 41. Diffusion source selection unit; 42. Localized application unit; 43. Layer thickness control unit; 5. Diffusion source status detection module; 51. Status acquisition unit; 52. Status evaluation unit; 6. Closed-loop compensation control module; 61. Threshold comparison unit; 62. Compensation command generation unit; 7. Partition thermal field grain boundary diffusion module; 71. Environmental control unit; 72. Main heating unit; 73. Partition heat input unit; 74. Cooling control unit; 8. Post-diffusion detection and grading module; 81. Post-diffusion detection unit; 82. Grade determination unit; 9. Feedback correction module; 91. Result correlation unit; 92. Parameter correction unit. Detailed Implementation

[0026] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0027] Example 1, as Figure 1 As shown, this embodiment provides a grain boundary diffusion treatment system for neodymium iron boron magnets used in new energy vehicle motors, used to treat sintered neodymium iron boron magnets for rotors of new energy vehicle drive motors. The magnet to be treated is a cuboid magnet, and the grade can be N48H, N48SH or N50UH. The magnet surface includes an outer surface near the air gap, an inner surface near the rotor shaft, two end faces and two side faces.

[0028] The NdFeB magnet grain boundary diffusion treatment system for new energy vehicle motors includes a motor parameter acquisition module 1, a partition modeling module 2, a magnet attitude positioning module 3, a diffusion source application module 4, a diffusion source state detection module 5, a closed-loop compensation control module 6, a partition thermal field grain boundary diffusion module 7, a post-diffusion detection and grading module 8, and a feedback correction module 9.

[0029] The motor parameter acquisition module 1 is used to acquire the structural parameters, operating condition parameters, and magnet assembly position parameters of the drive motor, forming motor operating condition data. Structural parameters include rotor outer diameter, stator inner diameter, air gap width, magnet slot position, magnet embedding depth, magnet pole arc angle, magnetic bridge thickness, and cooling channel position. Operating condition parameters include air gap magnetic flux density, peak current, rated current, maximum speed, field weakening operating range, peak torque duration, maximum operating temperature, and cooling boundary parameters. Magnet assembly position parameters include those near the air gap side, near the rotor shaft side, near the slot opening side, away from the slot opening side, end region, and middle region.

[0030] The motor parameter acquisition module 1 can be implemented using an industrial computer, a PLC controller, a data acquisition card, and a process database server. The industrial computer is configured with an 8-core or higher processor, at least 16GB of RAM, and a 1TB solid-state drive. The PLC controller can be a Siemens S7-1500, Beckhoff CX series, or an equivalent controller. Data communication interfaces include EtherCAT, Profinet, RS485, and Ethernet. The test environment temperature is controlled between 20℃ and 30℃, and the relative humidity is controlled between 30% and 60%. Motor operating condition data is obtained from a motor design database, finite element simulation results, bench test results, or vehicle operating condition records.

[0031] The partition modeling module 2 connects to the motor parameter acquisition module 1. It determines the demagnetization risk index of each evaluation region on the surface of the magnet to be processed based on motor operating data, and divides the surface into a first diffusion region, a second diffusion region, and a third diffusion region according to the demagnetization risk index, generating a diffusion execution parameter set. The partition modeling module 2 first divides the surface of the magnet to be processed into multiple non-overlapping evaluation regions, and then determines the demagnetization risk index based on the temperature parameters, demagnetization field parameters, magnetization direction parameters, and boundary distance parameters corresponding to each evaluation region. The demagnetization risk index is not limited by a fixed formula and can be obtained through a pre-calibrated demagnetization risk assessment model, a risk weight table, simulation result lookup rules, or an experimental calibration database.

[0032] In this embodiment, the first risk threshold is 0.70, and the second risk threshold is 0.40. When the demagnetization risk index is greater than or equal to 0.70, the corresponding area to be evaluated is designated as the first diffusion region; when the demagnetization risk index is less than 0.70 but greater than or equal to 0.40, the corresponding area to be evaluated is designated as the second diffusion region; and when the demagnetization risk index is less than 0.40, the corresponding area to be evaluated is designated as the third diffusion region. The first diffusion region is a high demagnetization risk region, the second diffusion region is a medium demagnetization risk region, and the third diffusion region is a low demagnetization risk region. The above threshold division clearly defines the boundaries of the three diffusion regions and avoids region overlap.

[0033] After processing by the partition modeling module 2, the two long side corner areas of the magnet near the air gap, the end area near the slot, and the local heat concentration area are divided into the first diffusion area; the middle area and end transition area of ​​the magnet near the air gap are divided into the second diffusion area; and the central area of ​​the magnet near the rotor shaft surface and away from the demagnetization field concentration location is divided into the third diffusion area.

[0034] The diffusion execution parameter set includes risk threshold parameters, diffusion source layer parameters, and heat treatment parameters. Risk threshold parameters include a first risk threshold and a second risk threshold used to delineate the first, second, and third diffusion regions. Diffusion source layer parameters include the diffusion source layer structure, heavy rare earth reinforcement layer thickness parameters, and diffusion source application amount. Heat treatment parameters include a target wetting evaluation threshold, zoned thermal input parameters, and compensation triggering conditions. The first diffusion region corresponds to a wetting promotion layer, a first heavy rare earth reinforcement layer, and a diffusion regulation layer. The thickness parameter of the first heavy rare earth reinforcement layer is 5 μm to 20 μm, the total thickness of the diffusion source is 8 μm to 40 μm, the target wetting evaluation threshold is 0.85, and the preferred qualified threshold is 0.95. The second diffusion region corresponds to a wetting promotion layer and a second heavy rare earth reinforcement layer. The thickness parameter of the second heavy rare earth reinforcement layer is 2 μm to 10 μm, the total thickness of the diffusion source is 3 μm to 25 μm, and the target wetting evaluation threshold is 0.75. The third diffusion region corresponds to a zero-thickness parameter for the heavy rare earth reinforcement layer. A grain boundary modification layer without a heavy rare earth reinforcement layer is used, with a thickness of 0 μm to 10 μm. Thermal shielding or reducing heat input is preferred to avoid excessive diffusion.

[0035] The magnet attitude positioning module 3 connects to the partition modeling module 2 and is used to identify the actual attitude of the magnet to be processed and map each diffusion region to the actual surface of the magnet. The magnet attitude positioning module 3 can be configured with an industrial camera, telecentric lens, ring light source, clamping fixture, servo flipping mechanism, and positioning reference block. The industrial camera has a resolution of no less than 12 megapixels and a positioning accuracy of no less than ±0.05mm; the servo flipping mechanism has a repeatability positioning accuracy of no less than ±0.02mm. The magnet attitude positioning module 3 identifies the end face, side face, corners, chamfers, air gap side surface, and subsequent motor assembly direction of the NdFeB magnet to be processed, obtaining magnet attitude data. Then, based on the magnet attitude data and assembly direction, it maps the first diffusion region, second diffusion region, and third diffusion region to the actual surface of the magnet. Through this mapping, areas with high demagnetization risk can be consistent with the actual coating area, avoiding the offset of the reinforced area due to incorrect magnet placement.

[0036] The diffusion source application module 4 connects to the partition modeling module 2 and the magnet attitude positioning module 3. It is used to perform corresponding diffusion source processing based on the diffusion execution parameter set and the actual surface, forming a first diffusion source layer, a second diffusion source layer, and a third diffusion source layer. The diffusion source application module 4 can be configured with surface cleaning equipment, plasma activation equipment, a localized spraying head, a dispensing head, a screen printing mechanism, a masking and confinement mechanism, a thickness control mechanism, and a diffusion source switching valve group. Surface cleaning can be performed using anhydrous ethanol ultrasonic cleaning and nitrogen drying. The plasma activation power is 200W to 500W, and the processing time is 30s to 180s, controlling the magnet surface roughness within the range of 0.2μm to 1.5μm. Localized application methods can include spraying, screen printing, dispensing, magnetron sputtering, evaporation, electrophoretic deposition, or transfer. This embodiment preferably uses a combination of micro-spraying and localized dispensing, with a spraying head orifice diameter of 0.2mm to 0.5mm and a motion platform repeatability accuracy of no less than ±0.02mm.

[0037] A first diffusion source layer is applied to the first diffusion region. This first diffusion source layer is a high-strength composite diffusion source layer, comprising, from the inside out, a Pr-Cu wetting promotion layer, a Tb-Cu first heavy rare earth reinforcement layer, and an Al-Cu-Ga diffusion regulation layer. The Pr-Cu wetting promotion layer has a thickness of 2 μm to 8 μm and is used to form a low-melting-point liquid phase at the diffusion temperature and improve the wetting of grain boundary inlets. The Tb-Cu first heavy rare earth reinforcement layer has a thickness of 5 μm to 20 μm and is used to provide heavy rare earth elements that improve coercivity to the grain boundaries in high demagnetization risk regions. The Al-Cu-Ga diffusion regulation layer has a thickness of 1 μm to 5 μm and is used to suppress surface oxidation and regulate the diffusion source migration rate. A second diffusion source layer is applied to the second diffusion region. This second diffusion source layer is a medium-strength composite diffusion source layer, comprising a Pr-Cu wetting promotion layer and a second heavy rare earth reinforcement layer. The second heavy rare earth reinforcement layer can be made of low-content Tb-Cu or Dy-Cu material, and its heavy rare earth content parameter is lower than that of the first heavy rare earth reinforcement layer. The total thickness is 3 μm to 15 μm. A third diffusion source layer is applied to the third diffusion region. This third diffusion source layer is a grain boundary modification layer without a heavy rare earth reinforcement layer and can be formed using Pr-Cu, Al-Cu, Nd-Cu, Ga-Cu, or combinations thereof. In this embodiment, the thickness of the third diffusion source layer is preferably less than 5 μm. It is used to improve the grain boundary state in the low demagnetization risk region but does not provide Dy, Tb, or other heavy rare earth reinforcement components to the third diffusion region. Through this differentiated treatment, the high demagnetization risk region is strengthened, while the consumption of Dy, Tb, and other heavy rare earth elements is reduced in the low demagnetization risk region.

[0038] The diffusion source status detection module 5 is connected to the diffusion source application module 4 and is used to detect the thickness and coverage status of the diffusion source layer in each diffusion region, generating a diffusion source status evaluation value. The diffusion source status detection module 5 can be configured with a laser confocal thickness gauge, a white light interferometer, a machine vision inspection device, an infrared thermal imager, and an image processing workstation. The laser confocal thickness gauge has a measuring range of 0μm to 100μm and a resolution of not less than 0.1μm; the machine vision inspection device is used to identify exposed substrate, cracks, agglomerations, accumulations, and sagging; the infrared thermal imager has a temperature measurement range of room temperature to 1000℃ and a temperature measurement accuracy of ±2℃ or ±2%.

[0039] The diffusion source status detection module 5 collects data on diffusion source layer thickness, coverage integrity, thickness uniformity, edge and corner coverage, melt spread, and local temperature status, and generates diffusion source status evaluation values ​​based on a preset evaluation table. In the preset evaluation table, coverage integrity, thickness uniformity, melt spread, and edge and corner coverage are all normalized to a value between 0 and 1. The diffusion source status evaluation values ​​are then output through a weighted table built into the control system. In the first diffusion region, the lower threshold for coverage integrity is 0.95, the lower threshold for edge and corner coverage is 0.90, and the diffusion source layer thickness deviation is controlled within ±15% of the target thickness. In the second diffusion region, the diffusion source layer thickness deviation is controlled within ±20% of the target thickness.

[0040] The closed-loop compensation control module 6 is connected to the diffusion source status detection module 5 and is used to generate compensation instructions based on the diffusion source status evaluation value. The closed-loop compensation control module 6 can adopt a collaborative control method using an industrial computer and a PLC, with a control cycle of no more than 100ms. The closed-loop compensation control module 6 controls the diffusion source application module 4 to perform recoating according to the recoating instructions, and controls the zoned thermal field grain boundary diffusion module 7 to perform heat treatment compensation according to heat treatment compensation instructions. Heat treatment compensation instructions include one or more of the following: local heating instructions, heat preservation correction instructions, secondary grain boundary diffusion instructions, and cooling protection instructions.

[0041] In the first diffusion region, when the diffusion source status evaluation value is less than 0.85, it is determined to be insufficient wetting. The closed-loop compensation control module 6 generates a recoating command and a local heating command, controls the diffusion source application module 4 to apply a Pr-Cu wetting promotion layer or a Tb-Cu first heavy rare earth reinforcement layer, and controls the partitioned thermal field grain boundary diffusion module 7 to perform local heating. When the diffusion source status evaluation value is greater than or equal to 0.85 and less than 0.95, it is determined to be slightly insufficient, and the closed-loop compensation control module 6 generates a heat preservation correction command or a local heating command. When the diffusion source status evaluation value is greater than or equal to 0.95, it is determined to be qualified. In the second diffusion region, when the diffusion source status evaluation value is less than 0.75, it is determined to be insufficient wetting, and a slight recoating or heat preservation correction is performed. When the diffusion source status evaluation value is greater than or equal to 0.75, it is determined to be qualified. In the third diffusion region, heavy rare earth wetting compensation is not mandatory. Surface correction is only performed when there is exposed substrate, agglomeration, obvious oxidation, or abnormal surface condition, and no heavy rare earth reinforcement layer is added.

[0042] The partitioned thermal field grain boundary diffusion module 7 connects to the partitioned modeling module 2, the diffusion source state detection module 5, and the closed-loop compensation control module 6. It is used to perform partitioned grain boundary diffusion heat treatment based on the diffusion execution parameter set, diffusion source state evaluation values, and compensation instructions to obtain the diffused magnet. The partitioned thermal field grain boundary diffusion module 7 can be configured with a diffusion furnace, vacuum device, inert atmosphere device, main heating device, local supplementary heating device, adjustable thermal shielding device, temperature acquisition device, and cooling control device. The diffusion furnace body adopts a graphite-heated vacuum furnace or a metal hot zone vacuum furnace, with an ultimate vacuum degree not exceeding 1 Pa; the vacuum device uses a combination of rotary vane pump and molecular pump; the inert atmosphere device introduces argon, nitrogen, or an argon-nitrogen mixture, with a gas purity not less than 99.999%; the oxygen content analyzer has a range of 0 ppm to 1000 ppm and a resolution of 1 ppm; the local heating device can use an infrared heater, induction heating coil, or resistance local heating block; the adjustable thermal shielding device can use molybdenum sheet, graphite plate, or ceramic heat insulation plate; the temperature acquisition device includes a K-type thermocouple, an infrared thermometer, and an infrared thermal imager.

[0043] The partitioned grain boundary diffusion heat treatment is carried out under vacuum or a low-oxygen inert atmosphere. The diffusion furnace is first evacuated to below 1 Pa, and then argon gas is introduced to reduce the oxygen content in the furnace cavity to below 30 ppm. In the first heating stage, the main heating device raises the magnet from room temperature to 500°C to 650°C. In the wetting and spreading stage, the furnace temperature is maintained in the range of 500°C to 750°C for 10 min to 120 min; in this embodiment, the furnace temperature is preferably raised to 600°C and maintained for 30 min to 90 min, allowing the Pr-Cu wetting promotion layer to form a liquid phase and spread along the grain boundary inlet. In the grain boundary diffusion stage, the furnace temperature is raised to the range of 750°C to 950°C and maintained for 1 h to 12 h; in this embodiment, the furnace temperature is preferably raised to 850°C to 920°C and maintained for 3 h to 8 h, allowing the Tb element to diffuse along the grain boundary into the interior of the magnet. During the homogenization and cooling stage, the furnace temperature is reduced to 400°C to 600°C and maintained for 0.5h to 5h; in this embodiment, it is preferably reduced to 500°C to 560°C and maintained for 1h to 3h, and then cooled to below 100°C under an inert atmosphere before being removed from the furnace.

[0044] During the grain boundary diffusion stage, the partitioned thermal field grain boundary diffusion module 7 adjusts the local heat input according to the first diffusion region, the second diffusion region, and the third diffusion region. The equivalent heat input corresponding to the first diffusion region is greater than that corresponding to the second diffusion region, and the equivalent heat input corresponding to the second diffusion region is greater than or equal to that corresponding to the third diffusion region. The equivalent heat input of the first diffusion region is 5% to 15% higher than that of the third diffusion region, preferably 5% to 12% in this embodiment; the equivalent heat input of the second diffusion region is 0% to 8% higher than that of the third diffusion region. In the same magnet to be processed or in the same batch of processing parameters, the actual selected equivalent heat input increment of the first diffusion region is always greater than that of the actual selected equivalent heat input increment of the second diffusion region, and the actual selected equivalent heat input increment of the second diffusion region is greater than or equal to that of the actual selected equivalent heat input increment of the third diffusion region. When the actual temperature of the first diffusion region is more than 10°C lower than the target temperature and lasts for more than 3 minutes, the closed-loop compensation control module 6 increases the local heating power; when the actual temperature of the third diffusion region is more than 15°C higher than the target temperature, the closed-loop compensation control module 6 reduces the main heating power or enhances the heat insulation effect of the adjustable thermal shielding device.

[0045] The post-diffusion detection and grading module 8 connects to the partitioned thermal field grain boundary diffusion module 7 and is used to detect the diffused magnet and determine the diffusion level. The post-diffusion detection and grading module 8 can be configured with magnetic flux scanning equipment, eddy current detection equipment, surface composition detection equipment, local magnetic property detection equipment, and appearance inspection equipment. Magnetic flux scanning can use a three-dimensional Hall magnetic flux scanning platform or a Helmholtz coil, with a magnetic flux measurement repeatability of no less than ±0.5%; eddy current detection frequency can be selected from 100kHz to 2MHz; surface composition detection can use an X-ray fluorescence analyzer, laser-induced breakdown spectrometer, or energy dispersive spectroscopy; local magnetic property detection can use a local hysteresis loop test device or an open-circuit flux loss test device; appearance inspection uses a machine vision camera to identify cracks, spalling, oxide spots, diffusion source residue anomalies, and edge defects.

[0046] The post-diffusion detection and grading module 8 generates a diffusion quality evaluation value based on the post-diffusion detection data. The diffusion quality evaluation value is not limited by a fixed formula and can be determined through a grading evaluation table based on magnetic flux consistency, eddy current detection results, surface composition detection results, local magnetic performance detection results, and appearance inspection results. The threshold for the first grade is 0.90, and the threshold for the second grade is 0.75. When the diffusion quality evaluation value is greater than or equal to 0.90, the diffused magnet is determined to be a first-grade magnet, suitable for high-demagnetization-risk assembly positions in drive motors, such as near the air gap side, slot side, or high-temperature concentrated areas; when the diffusion quality evaluation value is less than 0.90 but greater than or equal to 0.75, the diffused magnet is determined to be a second-grade magnet, suitable for medium-demagnetization-risk positions; when the diffusion quality evaluation value is less than 0.75, the diffused magnet is determined to be a third-grade magnet, suitable for low-demagnetization-risk positions or ordinary rotor areas.

[0047] The feedback correction module 9 connects to the post-diffusion detection and grading module 8, the partition modeling module 2, the diffusion source application module 4, and the partitioned thermal field grain boundary diffusion module 7. It is used to correct the diffusion execution parameter set for subsequent batches based on the diffusion level. The feedback correction module 9 can utilize a process database server and an edge computing controller to store process data for the same motor platform, the same magnet assembly location, and the same magnet batch. The feedback correction module 9 correlates the diffusion level with motor operating condition data, demagnetization risk index, diffusion source layer parameters, and heat treatment parameters to obtain batch-related data, and generates feedback correction parameters based on this data. Preset operating condition matching conditions can be set as follows: identical magnet assembly location parameters, peak current difference not exceeding 5%, maximum operating temperature difference not exceeding 5℃, air gap magnetic flux density difference not exceeding 3%, weak magnetic field operating range difference not exceeding 5%, and cooling boundary parameter difference not exceeding 10%.

[0048] The feedback and correction rules are as follows: If the local magnetic properties of the first diffusion region of three or more magnets in the same assembly position are lower than the target range, the feedback correction module 9 corrects one or more parameters in the diffusion execution parameter set. These parameters include a first risk threshold, a second risk threshold, a heavy rare earth reinforcement layer thickness parameter, the amount of diffusion source applied, or a zoned heat input parameter. If the remanence of the third diffusion region of three or more magnets in the same assembly position decreases, or if the migration of heavy rare earth elements from adjacent diffusion regions leads to excessive enrichment of heavy rare earth elements in the third diffusion region, the feedback correction module 9 reduces the amount of grain boundary modification layer applied in the third diffusion region, reduces the zoned heat input parameter of the third diffusion region, or enhances the corresponding heat shielding parameter of the third diffusion region. If the diffusion quality evaluation value of the second diffusion region remains near the second-level threshold for a long period, the feedback correction module 9 increases the target wetting evaluation threshold of the second diffusion region or extends the holding time. Through this feedback correction method, the post-diffusion test results are no longer solely used as quality judgment results, but rather as a basis for correcting process parameters in subsequent batches.

[0049] The working principle of this embodiment is as follows: The motor parameter acquisition module 1 first acquires the rotor structure, magnet slot position, air gap magnetic flux density, peak current, field weakening operation range, maximum operating temperature and cooling boundary conditions of the new energy vehicle drive motor to form motor operating condition data; The partition modeling module 2 determines the demagnetization risk index of different regions on the surface of the magnet to be processed based on motor operating data and calibration rules, and divides the magnet surface into the first diffusion region, the second diffusion region and the third diffusion region. The magnet attitude positioning module 3 performs loading identification and attitude positioning on the magnet to be processed, determines the end face, side, corner, chamfer, air gap side surface and final assembly direction, and maps the partitioning results to the actual magnet surface; The diffusion source application module 4 cleans and activates the magnet surface, and then applies a first diffusion source layer to the first diffusion region, a second diffusion source layer to the second diffusion region, and a third diffusion source layer to the third diffusion region according to the partitioning results. The diffusion source status detection module 5 detects the diffusion source layer thickness, coverage integrity, thickness uniformity, edge and corner coverage, and melt spreading degree, and generates diffusion source status evaluation values; The closed-loop compensation control module 6 generates a recoating instruction or a heat treatment compensation instruction based on the diffusion source status evaluation value and the corresponding area threshold. The zoned thermal field grain boundary diffusion module 7 completes heating, wetting and spreading, grain boundary diffusion and homogenization cooling in a vacuum or low oxygen inert atmosphere, and adjusts the local heat input according to different diffusion regions; the diffusion post-detection and grading module 8 performs magnetic flux, eddy current, surface composition, local magnetic properties and appearance detection on the diffused magnet to determine the diffusion level and the appropriate new energy vehicle motor assembly position. The feedback correction module 9 feeds back the detection results after diffusion to the subsequent batch process control to correct the diffusion execution parameter set of magnets in the same assembly position; wherein, the diffusion execution parameter set includes demagnetization risk zone threshold, diffusion source application amount, local heat input or heat shielding parameters.

[0050] Through the aforementioned system and process, the high demagnetization risk region can achieve more complete heavy rare earth grain boundary diffusion and higher coercivity; the medium demagnetization risk region can reduce the amount of heavy rare earth elements used while ensuring anti-demagnetization performance; and the low demagnetization risk region can reduce or avoid the application of heavy rare earth reinforcement layers, reduce the overall consumption of heavy rare earth elements such as Dy and Tb, and reduce remanence loss. Diffusion source state detection and closed-loop compensation control improve the stability of diffusion source coating, melt wetting, and heat treatment; post-diffusion detection grading and feedback correction improve the consistency of subsequent batch processes, making it suitable for batch grain boundary diffusion treatment of NdFeB magnets for new energy vehicle drive motors.

[0051] Example 2, as Figures 2-5 As shown, this embodiment, based on Embodiment 1, further illustrates the specific structure and collaborative working method of the partition modeling module 2, the magnet attitude positioning module 3, the diffusion source application module 4, and the diffusion source state detection module 5. The content already described in Embodiment 1 will not be repeated in this embodiment.

[0052] The motor parameter acquisition module 1 includes a motor structure parameter input unit, an operating condition input unit, and a magnet assembly position input unit. The motor structure parameter input unit acquires the rotor outer diameter, stator inner diameter, air gap width, magnet slot structure, magnet embedding depth, magnet pole arc angle, magnetic bridge thickness, and cooling channel position of the new energy vehicle drive motor. The operating condition input unit acquires the motor's peak current, rated current, maximum speed, field weakening operating range, peak torque duration, maximum operating temperature, and coolant temperature. The magnet assembly position input unit acquires the preset assembly position of the magnet to be processed in the motor rotor. The preset assembly positions include those near the air gap side, near the rotor shaft side, near the slot side, away from the slot side, the end region, and the middle region. These various data types collectively form the motor operating condition data, which serves as the input basis for subsequent demagnetization risk zoning and diffusion execution parameter generation.

[0053] The partitioning modeling module 2 includes a region division unit 21, a risk parameter extraction unit 22, a demagnetization risk calculation unit 23, a partition determination unit 24, and a parameter mapping unit 25. The region division unit 21 is used to divide the surface of the magnet to be processed into multiple non-overlapping regions based on motor operating data and the surface of the magnet to be processed. Each region can be divided according to the long side direction, short side direction, end face direction, corner position, chamfer position, and relative position to the air gap side or slot side of the magnet's outer surface, ensuring that each region has a unique spatial range and avoiding overlap between different diffusion regions.

[0054] The risk parameter extraction unit 22 is connected to the evaluation area division unit 21 and is used to extract corresponding temperature parameters, demagnetizing field parameters, magnetization direction parameters, and boundary distance parameters based on motor operating data and each evaluation area. The temperature parameter characterizes the predicted operating temperature of the evaluation area during motor operation; the demagnetizing field parameter characterizes the intensity of the reverse demagnetizing field experienced by the evaluation area; the magnetization direction parameter characterizes the angle between the magnetization direction and the local demagnetizing field direction of the evaluation area; and the boundary distance parameter characterizes the distance from the evaluation area to the corner of the magnet or the adjacent boundary of the slot.

[0055] The demagnetization risk calculation unit 23 is connected to the risk parameter extraction unit 22 and is used to calculate the demagnetization risk index of each area to be evaluated based on temperature parameters, demagnetization field parameters, magnetization direction parameters, and boundary distance parameters. The demagnetization risk index is determined in the following manner: ; ; in, Indicates the area number to be evaluated. It is a positive integer; Indicates the first magnet surface The demagnetization risk index of each region to be evaluated is a dimensionless parameter. Indicates the first The comprehensive demagnetization driving force of each region to be evaluated is a dimensionless parameter. Indicates the first The predicted working temperature for each area to be evaluated is given in degrees Celsius. This indicates the reference operating temperature, in degrees Celsius. This indicates the temperature normalization range, expressed in degrees Celsius. Indicates the first The reverse demagnetizing field strength of the region to be evaluated is expressed in amperes per meter. This indicates the strength of the reference reverse demagnetizing field, measured in amperes per meter. Indicates the first The angle between the magnetization direction and the local demagnetization direction of the region to be evaluated is expressed in radians. Indicates the first The distance from the area to be evaluated to the corner of the magnet or the adjacent boundary of the slot, in millimeters; This represents a distance attenuation reference value, in millimeters. , , and These represent the temperature influence coefficient, demagnetization field influence coefficient, direction influence coefficient, and boundary influence coefficient, respectively, all of which are dimensionless parameters.

[0056] In the above calculation method for the demagnetization risk index, the temperature, demagnetization field, direction, and boundary distance terms are all dimensionless quantities. Therefore, the overall demagnetization driving force is... As a dimensionless parameter, it can be used for exponential function calculations. This method can incorporate motor operating temperature rise, reverse demagnetizing field strength, magnetization direction angle, and proximity effects of corners or slots into the risk assessment of the region to be evaluated. This makes areas near the air gap side, slot side, corners, and heat concentration locations more likely to be identified as high demagnetizing risk areas, thus providing a basis for the subsequent differentiated setting of diffusion source layer structure and thermal input parameters.

[0057] The partitioning determination unit 24 is connected to the demagnetization risk calculation unit 23 and is used to partition each area to be evaluated according to the demagnetization risk index. The first risk threshold is 0.70, and the second risk threshold is 0.40. The first risk threshold is greater than the second risk threshold. When R a When R is greater than or equal to 0.70, the corresponding region to be evaluated is classified as the first diffusion region; when R... a When R is greater than or equal to 0.40 and less than 0.70, the corresponding region to be evaluated is classified as the second diffusion region; when R... a When the value is less than 0.40, the corresponding area to be evaluated is divided into a third diffusion region. The first diffusion region is a high demagnetization risk region, the second diffusion region is a medium demagnetization risk region, and the third diffusion region is a low demagnetization risk region. Preferably, the first diffusion region includes the long side corner region of the magnet near the air gap side, the end region near the rotor slot side, and the local heat concentration region; the second diffusion region includes the middle region of the air gap side and the end transition region; the third diffusion region includes the central region near the rotor shaft side surface or away from the location of the demagnetization field concentration.

[0058] The parameter mapping unit 25 is connected to the partition determination unit 24 and is used to generate corresponding diffusion execution parameters based on the first diffusion region, the second diffusion region, and the third diffusion region, forming a diffusion execution parameter set. The diffusion execution parameter set includes risk threshold parameters, diffusion source layer parameters, and heat treatment parameters. The risk threshold parameters include a first risk threshold and a second risk threshold; the diffusion source layer parameters include the diffusion source layer structure, the heavy rare earth reinforcement layer thickness parameter, and the diffusion source application amount; the heat treatment parameters include the target wetting evaluation threshold, the partitioned thermal input parameter, and the compensation trigger condition. Specifically, the heavy rare earth reinforcement layer thickness parameter corresponding to the first diffusion region is greater than that corresponding to the second diffusion region, and the heavy rare earth reinforcement layer thickness parameter corresponding to the third diffusion region is zero.

[0059] In this embodiment, the demagnetization risk partitioning results and diffusion execution parameters form the following correspondence: when When the value is greater than or equal to 0.70, the corresponding region is the first diffusion region. The diffusion source layer structure includes a wetting promotion layer, a heavy rare earth reinforcement layer, and a diffusion regulation layer. The thickness of the heavy rare earth reinforcement layer is 5 micrometers to 20 micrometers, and the total thickness of the diffusion source is 8 micrometers to 40 micrometers. The heat input strategy is local heat supplementation with an equivalent heat input increase of 5% to 15%, and the wetting evaluation threshold is not lower than 0.85. When the value is greater than or equal to 0.40 and less than 0.70, the corresponding region is the second diffusion region. The diffusion source layer structure includes a wetting promotion layer and a low-content heavy rare earth reinforcement layer. The thickness of the heavy rare earth reinforcement layer is 2 micrometers to 10 micrometers, and the total thickness of the diffusion source is 3 micrometers to 25 micrometers. The heat input strategy is conventional heat input or mild supplemental heating, with an equivalent heat input increase of 0% to 8%. The wetting evaluation threshold is not less than 0.75. When the value is less than 0.40, the corresponding region is the third diffusion region. The diffusion source layer structure is a low-melting-point grain boundary modification layer without a heavy rare earth reinforcement layer. The thickness parameter of the heavy rare earth reinforcement layer is zero, and the thickness of the grain boundary modification layer is 0 to 10 micrometers. The heat input strategy is to avoid overheating, and thermal insulation shielding is set when necessary. Heavy rare earth wetting compensation is not mandatory. Through this correspondence, the demagnetization risk zoning results can be directly applied to the physical diffusion treatment, establishing a clear correlation between the diffusion source layer structure, diffusion source thickness, local heat input, wetting evaluation threshold, and demagnetization risk index.

[0060] The magnet attitude positioning module 3 includes an attitude recognition unit 31, an assembly direction recognition unit 32, and a partition mapping unit 33. In specific equipment configurations, the magnet attitude positioning module 3 may also include a loading recognition unit, a visual positioning unit, a corner recognition unit, an attitude correction unit, and a partition projection unit. The attitude recognition unit 31 is used to identify the end face, side face, corners, chamfers, and air gap side surface of the magnet to be processed, obtaining magnet attitude data. The loading recognition unit is used to read the batch code or tray position code of the NdFeB magnet to be processed; the visual positioning unit is used to acquire an image of the magnet's shape and identify the magnet's long side, short side, end face, chamfer, and notch; the corner recognition unit is used to determine the position of the magnet's corners and the target surface near the air gap side.

[0061] Assembly direction recognition unit 32 is connected to attitude recognition unit 31 and is used to determine the assembly direction of the magnet to be processed in the drive motor based on motor operating data and magnet attitude data. Attitude correction unit is used to adjust the magnet attitude through a clamping mechanism or bearing fixture, ensuring that the actual placement direction of the magnet is consistent with the direction in the demagnetization risk zoning model. Zoning mapping unit 33 is connected to assembly direction recognition unit 32 and is used to map the first diffusion region, second diffusion region, and third diffusion region onto the actual surface of the magnet to be processed based on magnet attitude data, assembly direction, and the first, second, and third diffusion regions. Zoning projection unit is used to project the first, second, and third diffusion regions onto the actual surface of the magnet. Through magnet attitude positioning module 3, high demagnetization risk areas can accurately correspond to the actual magnet surface, avoiding insufficient diffusion source application to high demagnetization risk areas due to incorrect magnet placement orientation.

[0062] The diffusion source application module 4 includes a diffusion source selection unit 41, a localized application unit 42, and a layer thickness control unit 43. In specific device configurations, the diffusion source application module 4 may further include a surface activation unit, a diffusion source switching unit, and a shielding and confinement unit. The surface activation unit is used to clean, plasma-activate, lightly sandblast, laser-texturize, or chemically activate the magnet surface before applying the diffusion source, controlling the magnet surface roughness Ra within the range of 0.2 micrometers to 1.5 micrometers. This surface condition improves the adhesion stability of the diffusion source and reduces the risk of cracking, detachment, or agglomeration of the diffusion source during subsequent heating.

[0063] The diffusion source selection unit 41 is used to select the diffusion source layer type for the corresponding diffusion region according to the diffusion source layer parameters. The diffusion source switching unit is used to switch the diffusion source composition according to the diffusion region, so that the first diffusion region, the second diffusion region, and the third diffusion region obtain the corresponding diffusion source material respectively. The localization application unit 42 is connected to the diffusion source selection unit 41 and is used to apply the first diffusion source layer to the first diffusion region, the second diffusion source layer to the second diffusion region, and the third diffusion source layer to the third diffusion region according to the diffusion source layer type and the actual surface of the magnet to be processed. The localization application unit 42 can apply the diffusion source to the corresponding diffusion region by spraying, screen printing, dispensing, magnetron sputtering, evaporation, electrophoretic deposition, or transfer. The layer thickness control unit 43 is connected to the localization application unit 42 and is used to control the diffusion source layer thickness of each diffusion region according to the diffusion source application amount. The shielding and confinement unit is used to shield the third diffusion region or the region where heavy rare earth diffusion sources are not needed, so as to limit the migration of heavy rare earth diffusion sources to the low demagnetization risk region.

[0064] The first diffusion source layer of the first diffusion region is a composite diffusion source layer, comprising, from the inside out, a wetting promotion layer, a first heavy rare earth strengthening layer, and a diffusion regulation layer. The wetting promotion layer directly contacts the magnet substrate and its composition includes Pr-Cu, Nd-Cu, Al-Cu, Ga-Cu, or combinations thereof, used to form a low-melting-point liquid phase at the diffusion temperature and improve grain boundary inlet wetting. The first heavy rare earth strengthening layer includes Tb, Dy, Tb-Cu, Dy-Cu, Tb-Al, Dy-Al, or a Tb-Dy alloy, used to provide heavy rare earth elements that improve coercivity to grain boundaries in high demagnetization risk regions. The diffusion regulation layer includes one or more of Al, Cu, Ga, Pr, or rare earth fluorides, used to suppress excessive surface oxidation and regulate the diffusion source migration rate. Through the layered combination of the wetting promotion layer, the first heavy rare earth strengthening layer, and the diffusion regulation layer, the first diffusion region can achieve a strong heavy rare earth strengthening effect while improving grain boundary inlet wetting.

[0065] The second diffusion source layer in the second diffusion region includes a wetting promotion layer and a second heavy rare earth reinforcement layer. The second heavy rare earth reinforcement layer is a low-content heavy rare earth reinforcement layer, and its heavy rare earth content parameter is lower than that of the first heavy rare earth reinforcement layer. The thickness of the second heavy rare earth reinforcement layer is also less than that of the first heavy rare earth reinforcement layer in the first diffusion region. A third diffusion source layer is applied to the third diffusion region. This third diffusion source layer is a grain boundary modification layer without a heavy rare earth reinforcement layer. The third diffusion source layer can be formed using Pr-Cu, Al-Cu, Nd-Cu, Ga-Cu, or a combination thereof, to improve the grain boundary state in the low demagnetization risk region, but does not provide heavy rare earth reinforcement components such as Dy and Tb to the third diffusion region. Through this design, the second diffusion region can achieve a moderate increase in coercivity, and the third diffusion region can reduce heavy rare earth consumption in the low-risk region and reduce remanence loss.

[0066] The diffusion source state detection module 5 includes a state acquisition unit 51 and a state evaluation unit 52. In specific device configurations, the diffusion source state detection module 5 may also include a coating thickness detection unit, a surface continuity detection unit, an edge / corner coverage detection unit, an infrared temperature detection unit, and a wetting state identification unit. The state acquisition unit 51 is used to acquire the diffusion source layer thickness, coverage integrity, thickness uniformity, and edge / corner coverage degree of each diffusion region after the diffusion source is applied, and to acquire the melting and spreading degree of each diffusion region during the heating stage of the partitioned grain boundary diffusion heat treatment, thus obtaining diffusion source state data. The coating thickness detection unit is used to detect the diffusion source layer thickness; the surface continuity detection unit is used to identify whether the diffusion source layer has exposed substrate, cracks, agglomeration, accumulation, or sagging; the edge / corner coverage detection unit is used to determine whether the edges and chamfers in the first diffusion region are completely covered by the diffusion source; the infrared temperature detection unit is used to acquire the surface temperature of different regions during the heating process; and the wetting state identification unit is used to determine whether the diffusion source has reached a molten and wetted state based on changes in brightness, reflectivity, temperature, or edge spreading morphology of the diffusion source layer during the heating process.

[0067] The status evaluation unit 52 is connected to the status acquisition unit 51 and is used to generate diffusion source status evaluation values ​​for each diffusion region based on the diffusion source status data. The diffusion source status evaluation values ​​adopt the effective wetting evaluation values ​​of the diffusion source. The effective wetting evaluation value of the diffusion source is determined in the following manner: ; Where b represents the detection area number, and b is a positive integer; This represents the effective wetting evaluation value of the diffusion source in the b-th detection area, which is a dimensionless parameter. This represents the coverage integrity of the b-th detection area, and is a dimensionless parameter with a value range of 0 to 1; This represents the thickness uniformity of the b-th detection area, which is a dimensionless parameter with a value range of 0 to 1; This represents the degree of melt spread in the b-th detection area. It is a dimensionless parameter with a value range of 0 to 1. This represents the degree of corner coverage of the b-th detection region. It is a dimensionless parameter with a value range of 0 to 1. , , and These represent the weights for complete coverage, thickness uniformity, melt spread, and edge / corner coverage, respectively, all of which are dimensionless parameters. , , and The sum of is 1.

[0068] in, Determined based on the ratio of actual coverage area to target coverage area; The thickness is determined based on the normalized evaluation results of the diffusion source layer thickness deviation relative to the target thickness within the detection area; the smaller the thickness deviation, the better. The closer the value is to 1, the greater the thickness deviation. The closer to 0; Determined based on the ratio of the spreading boundary area after the diffusion source melts to the target spreading area; It is determined based on the ratio of the corner coverage length to the target coverage length.

[0069] In the calculation method of the effective wetting evaluation value of the above diffusion source, the coverage integrity, thickness uniformity, melt spreading degree, and edge and corner coverage degree are all dimensionless evaluation parameters, which can jointly reflect whether the diffusion source layer has reached the state where it can enter the grain boundary diffusion stage. Among them, the edge and corner coverage degree can reflect whether the edges and corners in the first diffusion region are fully covered, the melt spreading degree can reflect whether the wetting promotion layer spreads along the grain boundary entrance during the heating stage, and the thickness uniformity can reflect whether there are local thinning or accumulation of the heavy rare earth reinforcement layer. Through this evaluation method, the diffusion source state detection module 5 can unify multiple detection results into diffusion source state evaluation values, providing a quantitative basis for the closed-loop compensation control module 6 to generate recoating instructions or heat treatment compensation instructions.

[0070] In this embodiment, when the effective wetting evaluation value of the diffusion source in the first diffusion region is lower than 0.85, the diffusion source in the first diffusion region is determined to be insufficiently wetted; when the effective wetting evaluation value of the diffusion source in the second diffusion region is lower than 0.75, the diffusion source in the second diffusion region is determined to be insufficiently wetted; the third diffusion region is not forced to undergo heavy rare earth wetting compensation, but when exposed substrate, cracks, agglomeration, accumulation, sagging, or obvious oxidation is detected, the surface condition of the third diffusion region is determined to be abnormal. Through the above-mentioned condition evaluation method, the diffusion source condition detection module 5 can convert the diffusion source layer thickness, coverage integrity, thickness uniformity, edge and corner coverage degree, and melt spreading degree into diffusion source condition evaluation values ​​that can be used for closed-loop compensation control.

[0071] The working principle of this embodiment is as follows: The motor parameter acquisition module 1 first generates motor operating condition data through the motor structure parameter input unit, the operating condition input unit, and the magnet assembly position input unit; The evaluation area division unit 21 in the partition modeling module 2 establishes multiple non-overlapping evaluation areas based on the motor operating data and the surface of the magnet to be processed. Risk parameter extraction unit 22 extracts temperature parameters, demagnetization field parameters, magnetization direction parameters, and boundary distance parameters from each region to be evaluated; demagnetization risk calculation unit 23 calculates the demagnetization risk index for each region to be evaluated. The partitioning determination unit 24 divides the first diffusion region, the second diffusion region, and the third diffusion region based on two risk thresholds of 0.70 and 0.40. The parameter mapping unit 25 generates corresponding diffusion execution parameters according to different diffusion regions, so that the demagnetization risk zoning results are transformed into diffusion source layer structure, heavy rare earth reinforcement layer thickness parameters, diffusion source application amount, zoning thermal input parameters and wetting evaluation threshold.

[0072] Subsequently, the magnet attitude positioning module 3 identifies the end face, side face, corners, chamfers, air gap side surface, and assembly direction, and maps each diffusion region to the actual surface of the magnet to be processed. The diffusion source application module 4 applies the corresponding diffusion source layer to the first, second, and third diffusion regions according to the diffusion source layer parameters. The diffusion source state detection module 5 collects the diffusion source layer thickness, coverage integrity, thickness uniformity, corner coverage degree, and melt spreading degree, and generates diffusion source state evaluation values, providing a basis for closed-loop compensation control and subsequent partitioned grain boundary diffusion heat treatment.

[0073] Through the structure and operation described in this embodiment, the demagnetization risk zoning is no longer merely a display or evaluation result, but can be directly converted into physical processing parameters such as diffusion source layer structure, heavy rare earth reinforcement layer thickness, local heat input, and wetting evaluation threshold. The first diffusion region can obtain more sufficient heavy rare earth diffusion reinforcement, the second diffusion region can obtain moderate reinforcement, and the third diffusion region can reduce or avoid the application of heavy rare earth reinforcement layers. This improves the demagnetization resistance of high demagnetization risk regions while reducing heavy rare earth consumption and remanent magnetization loss in low demagnetization risk regions. The magnet attitude positioning module 3 ensures that the zoning results are accurately applied to the actual magnet surface, and the diffusion source state detection module 5 enables the diffusion source layer state to be quantitatively evaluated, thereby improving the consistency and controllability of grain boundary diffusion treatment for NdFeB magnets used in new energy vehicle motors.

[0074] Example 3, as Figures 6-9 As shown, this embodiment, based on Embodiments 1 and 2, further illustrates the specific implementation methods of the closed-loop compensation control module 6, the partitioned thermal field grain boundary diffusion module 7, the post-diffusion detection and grading module 8, and the feedback correction module 9. The content already described in Embodiments 1 and 2 will not be repeated in this embodiment.

[0075] The closed-loop compensation control module 6 is also connected to the diffusion source applying module 4. The closed-loop compensation control module 6 is configured to control the diffusion source applying module 4 to perform replenishment coating according to a replenishment coating instruction, and control the zoned thermal field grain boundary diffusion module 7 to perform heat treatment compensation according to a heat treatment type compensation instruction. The closed-loop compensation control module 6 comprises a threshold comparison unit 61 and a compensation instruction generation unit 62. The threshold comparison unit 61 is configured to compare the diffusion source state evaluation values of a first diffusion region and a second diffusion region with corresponding target wetting evaluation thresholds respectively, and determine surface state abnormality of a third diffusion region, so as to obtain a state comparison result. The compensation instruction generation unit 62 is connected to the threshold comparison unit 61, and is configured to generate the replenishment coating instruction and / or the heat treatment type compensation instruction when the state comparison result satisfies a corresponding compensation triggering condition. The heat treatment type compensation instruction comprises one or more of a local supplementary heating instruction, a heat preservation correction instruction, a secondary grain boundary diffusion instruction and a temperature reduction protection instruction.

[0076] In this embodiment, the diffusion source state evaluation value adopts an effective diffusion source wetting evaluation value to represent, which is determined according to the method in Embodiment 2. The target wetting evaluation threshold of the first diffusion region is 0.85, and the preferred qualified threshold is 0.95; the target wetting evaluation threshold of the second diffusion region is 0.75; the third diffusion region is not provided with a target wetting evaluation threshold for heavy rare earth wetting compensation, and the diffusion source state evaluation value thereof does not participate in the heavy rare earth wetting compensation threshold comparison, but is subjected to abnormality determination on surface state abnormalities such as bottom exposure, agglomeration, obvious oxidation, cracks, accumulation or sagging.

[0077] The specific compensation logic is as follows: In the first diffusion region, when is less than 0.85, the determination result is insufficient wetting, the closed-loop compensation control module 6 generates a replenishment coating instruction and a local supplementary heating instruction, and the replenishment coating object is a heavy rare earth reinforcement layer or a wetting promotion layer; when is greater than or equal to 0.85 and less than 0.95, the determination result is mild insufficiency, and the closed-loop compensation control module 6 generates an instruction for prolonging local heat preservation or an instruction for increasing local supplementary heating power; when is greater than or equal to 0.95, the determination result is qualified, and the to-be-processed magnet enters the grain boundary diffusion stage. In the second diffusion region, when is less than 0.75, the determination result is insufficient wetting, the closed-loop compensation control module generates a mild replenishment coating instruction or an instruction for prolonging heat preservation; when When the value is greater than or equal to 0.75, the judgment result is qualified, and the magnet to be processed enters the grain boundary diffusion stage. In the third diffusion region, when the diffusion source state detection module 5 detects exposed substrate, agglomeration, or obvious oxidation, the judgment result is an abnormal surface state, and the closed-loop compensation control module 6 generates a surface correction command. The surface correction command is used to control the diffusion source application module 4 to perform surface smoothing, cleaning, scraping, blowing, or supplementing of a grain boundary modification layer without heavy rare earth strengthening components in the third diffusion region, without adding a heavy rare earth strengthening layer. In this way, the third diffusion region can avoid the decrease in remanence caused by excessive heavy rare earth diffusion.

[0078] The closed-loop compensation control module 6 may also include an anomaly determination unit, a recoating control unit, a heat replenishment control unit, a thermal insulation correction unit, a secondary diffusion determination unit, and an over-diffusion protection unit. The anomaly determination unit is used to determine, based on the detection results of the diffusion source status detection module 5, whether there is insufficient diffusion source coverage, insufficient thickness, corner missed coating, surface agglomeration, insufficient wetting, local overheating, or over-diffusion risk. The recoating control unit is used to apply a second coating to areas with insufficient diffusion source coverage before heating or after preheating. The heat replenishment control unit is used to compensate for localized heat input in areas with insufficient wetting or insufficient diffusion at corners. The thermal insulation correction unit is used to correct the thermal insulation time based on the wetting state, temperature deviation, and diffusion source layer thickness. The secondary diffusion determination unit is used to determine whether to perform secondary grain boundary diffusion or localized supplementary grain boundary diffusion when the post-diffusion detection results do not meet the target level. The over-diffusion protection unit is used to reduce heat input or activate shielding and insulation when there is a risk of overheating or heavy rare earth migration in the third diffusion region.

[0079] The compensated diffusion source surface density is determined as follows: ; in, This represents the compensated diffusion source surface density, expressed in milligrams per square centimeter. This represents the initial diffusion source surface density, expressed in milligrams per square centimeter. This represents the target value for coverage completeness. It is a dimensionless parameter with a value range of 0 to 1. This represents the coverage integrity of the b-th detection area, and is a dimensionless parameter with a value range of 0 to 1; This represents the target value for thickness uniformity. It is a dimensionless parameter with a value range of 0 to 1. This represents the thickness uniformity of the b-th detection area, which is a dimensionless parameter with a value range of 0 to 1; This represents the target value for the degree of melt spread. It is a dimensionless parameter and its value ranges from 0 to 1. This represents the degree of melt spread in the b-th detection area. It is a dimensionless parameter with a value range of 0 to 1. This represents the target value for the degree of edge and corner coverage. It is a dimensionless parameter with a value range of 0 to 1. This represents the degree of corner coverage of the b-th detection region. It is a dimensionless parameter with a value range of 0 to 1. This represents the coverage insufficiency compensation coefficient, expressed in milligrams per square centimeter. This represents the thickness deficiency compensation coefficient, expressed in milligrams per square centimeter. This represents the compensation coefficient for insufficient spreading, expressed in milligrams per square centimeter. The value represents the compensation coefficient for insufficient coverage of the corners, in milligrams per square centimeter; max(0, x) means that when x is greater than 0, x is taken, and when x is less than or equal to 0, x is taken.

[0080] This compensation method ensures that the system only positively compensates for deficiencies in coverage integrity, thickness uniformity, melt spread, and edge / corner coverage, avoiding further increases in diffusion source areal density in areas where the diffusion source condition already meets requirements. Specifically, when the edge / corner coverage of the first diffusion region is lower than the target value, the edge / corner coverage deficiency term in the formula is positive, and the compensated diffusion source areal density increases accordingly, enabling the coating control unit to apply a wetting-promoting layer or heavy rare earth reinforcement layer to the corners or chamfers. When the thickness uniformity of the second diffusion region is lower than the target value, the thickness deficiency term in the formula is positive, guiding light coating or insulation correction. When all conditions in the third diffusion region meet the target values, all deficiencies are zero, and the diffusion source areal density no longer increases, thereby reducing heavy rare earth consumption and mitigating the risk of over-diffusion.

[0081] The partitioned thermal field grain boundary diffusion module 7 includes an environmental control unit 71, a main heating unit 72, a partitioned heat input unit 73, and a cooling control unit 74. The environmental control unit 71 provides a vacuum environment or a low-oxygen inert atmosphere environment for the magnet to be treated; the main heating unit 72 is connected to the environmental control unit 71 and is used to raise the overall temperature of the magnet to be treated according to the heat treatment parameters; the partitioned heat input unit 73 is connected to the main heating unit 72 and is used to apply corresponding equivalent heat inputs to the first diffusion region, the second diffusion region, and the third diffusion region according to the partitioned heat input parameters and heat treatment compensation instructions; the cooling control unit 74 is connected to the partitioned heat input unit 73 and is used to cool the magnet after partitioned grain boundary diffusion heat treatment to obtain the diffused magnet.

[0082] In its specific structure, the partitioned thermal field grain boundary diffusion module 7 includes a diffusion furnace body, a vacuum unit, an inert atmosphere unit, a main heating unit 72, a local heating unit, an adjustable thermal shielding unit, a temperature acquisition unit, and a cooling control unit 74. The diffusion furnace body houses the magnet to be processed and the supporting fixture. The vacuum unit evacuates the furnace cavity to below 10 Pa, preferably below 1 Pa, before diffusion. The inert atmosphere unit introduces argon, nitrogen, or an argon-nitrogen mixture into the furnace cavity and controls the oxygen content to below 100 ppm, preferably below 30 ppm. The main heating unit 72 provides overall heating. The local heating unit compensates for localized heat input to the magnet corners, air gap side surfaces, or adjacent areas of the slot corresponding to the first diffusion region. The adjustable thermal shielding unit provides thermal shielding for the third diffusion region to prevent excessive diffusion in low-demagnetization-risk areas. The temperature acquisition unit acquires the furnace cavity temperature, fixture temperature, and magnet surface area temperature. The cooling control unit 74 controls the cooling rate after diffusion.

[0083] The grain boundary diffusion heat treatment includes a first heating stage, a wetting and spreading stage, a grain boundary diffusion stage, and a homogenization cooling stage. The first heating stage raises the magnet from room temperature to 500°C to 650°C. The wetting and spreading stage maintains the temperature within the range of 500°C to 750°C for 10 to 120 minutes, allowing the wetting-promoting layer to form a liquid phase and spread along the grain boundary inlet. The grain boundary diffusion stage maintains the temperature within the range of 750°C to 950°C for 1 to 12 hours, allowing heavy rare earth elements to diffuse along the grain boundaries into the interior of the magnet. The homogenization cooling stage lowers the magnet to 400°C to 600°C and maintains the temperature for 0.5 to 5 hours to stabilize the grain boundary phase and reduce thermal stress.

[0084] During the grain boundary diffusion stage, the equivalent heat input corresponding to the first diffusion region is greater than that corresponding to the second diffusion region, and the equivalent heat input corresponding to the second diffusion region is greater than or equal to that corresponding to the third diffusion region. Specifically, the equivalent heat input of the first diffusion region is 5% to 15% higher than that of the third diffusion region; the equivalent heat input of the second diffusion region is 0% to 8% higher than that of the third diffusion region. When the actual temperature of the first diffusion region is more than 10 degrees Celsius lower than the target temperature and remains so for more than 3 minutes, the closed-loop compensation control module 6 controls the local heating unit to increase the heat input; when the actual temperature of the third diffusion region is more than 15 degrees Celsius higher than the target temperature, the closed-loop compensation control module 6 controls the adjustable thermal shielding unit to enhance insulation or reduce the main heating power. In this way, the first diffusion region can achieve more complete grain boundary diffusion, and the third diffusion region can reduce the risk of overheating and excessive migration of heavy rare earth elements.

[0085] The post-diffusion detection and grading module 8 includes a post-diffusion detection unit 81 and a grading unit 82. The post-diffusion detection unit 81 performs magnetic flux detection, eddy current detection, surface composition detection, local magnetic property detection, and appearance inspection on the diffused magnet to obtain post-diffusion detection data. The grading unit 82, connected to the post-diffusion detection unit 81, generates a diffusion quality evaluation value based on the post-diffusion detection data. When the diffusion quality evaluation value is greater than or equal to a first-grade threshold, the diffused magnet is classified as a first-grade magnet; when the diffusion quality evaluation value is less than the first-grade threshold but greater than or equal to a second-grade threshold, the diffused magnet is classified as a second-grade magnet; and when the diffusion quality evaluation value is less than the second-grade threshold, the diffused magnet is classified as a third-grade magnet. The first-grade threshold is greater than the second-grade threshold. In this embodiment, the first-grade threshold is 0.90, and the second-grade threshold is 0.75.

[0086] In its specific structure, the post-diffusion detection and grading module 8 includes a magnetic flux scanning unit, an eddy current detection unit, a surface composition detection unit, an appearance inspection unit, a local magnetic performance determination unit, and an assembly level determination unit 82. The magnetic flux scanning unit detects the consistency of magnetic flux distribution in different regions of the magnet. The eddy current detection unit detects changes in the surface and near-surface structure of the magnet after diffusion. The surface composition detection unit detects the relative content of heavy rare earth elements on the surface. The appearance inspection unit identifies cracks, spalling, oxide spots, abnormal diffusion source residues, and edge defects. The local magnetic performance determination unit determines the strengthening degree of the first and second diffusion regions. The assembly level determination unit 82 classifies the magnet into first-level, second-level, and third-level magnets based on the detection results. First-level magnets are suitable for high-demagnetization-risk locations in new energy vehicle drive motors, such as near the air gap side, slot side, or high-temperature concentrated areas. Second-level magnets are suitable for medium-demagnetization-risk locations. Third-level magnets are suitable for low-demagnetization-risk locations or ordinary rotor areas.

[0087] The feedback correction module 9 is also connected to the diffusion source application module 4 and the partitioned thermal field grain boundary diffusion module 7. The feedback correction module 9 includes a result association unit 91 and a parameter correction unit 92. The result association unit 91 is used to associate the diffusion level with motor operating condition data, demagnetization risk index, diffusion source layer parameters, and heat treatment parameters to obtain batch association data. The parameter correction unit 92 is connected to the result association unit 91 and is used to generate feedback correction parameters based on the batch association data. The feedback correction parameters are used to correct one or more parameters in the diffusion execution parameter set of magnets to be processed in subsequent batches that have the same magnet assembly position parameters or motor operating condition data that meets preset operating condition matching conditions; wherein, the one or more parameters in the diffusion execution parameter set include one or more of a first risk threshold, a second risk threshold, diffusion source layer parameters, and heat treatment parameters.

[0088] The feedback correction module 9 is used to feed back the post-diffusion detection results to the process control of subsequent batches. Specifically, when multiple magnets corresponding to the same assembly position exhibit insufficient coercivity or excessive flux loss rate after high-temperature demagnetization in the first diffusion region, the feedback correction module 9 corrects one or more parameters in the diffusion execution parameter set. These parameters include a first risk threshold, a second risk threshold, a heavy rare earth reinforcement layer thickness parameter, diffusion source application amount, or zoned heat input parameters. When multiple magnets corresponding to the same assembly position exhibit decreased remanence or excessive heavy rare earth enrichment in the third diffusion region, the feedback correction module 9 reduces the grain boundary modification layer application amount in the third diffusion region, reduces the zoned heat input parameters in the third diffusion region, or enhances the corresponding thermal shielding parameters in the third diffusion region. Through the feedback correction module 9, post-diffusion detection is no longer merely a quality management result, but becomes the basis for correcting the diffusion source application and heat treatment parameters for the next batch of magnets.

[0089] The working principle of this embodiment is as follows: After the diffusion source status detection module 5 generates the diffusion source status evaluation value for each diffusion region, the threshold comparison unit 61 in the closed-loop compensation control module 6 compares the diffusion source status evaluation values ​​of the first and second diffusion regions with the corresponding target wetting evaluation thresholds and compensation trigger conditions, and determines the surface state anomalies in the third diffusion region, such as exposure, agglomeration, obvious oxidation, cracks, accumulation, or sagging. The compensation instruction generation unit 62 generates a recoating instruction, a surface correction instruction, or a heat treatment compensation instruction based on the comparison results or the surface state anomaly determination results.

[0090] The recoating command controls the diffusion source application module 4 to recoat areas with insufficient diffusion source. The heat treatment compensation command controls the partitioned thermal field grain boundary diffusion module 7 to perform localized heating, heat preservation correction, secondary grain boundary diffusion, or cooling protection. Subsequently, the partitioned thermal field grain boundary diffusion module 7 performs the first heating, wetting and spreading, grain boundary diffusion, and homogenization cooling in a vacuum or low-oxygen inert atmosphere, ensuring that the first diffusion region receives an equivalent heat input higher than the second and third diffusion regions according to the partitioned heat input parameters. After diffusion is complete, the post-diffusion detection and grading module 8 determines the diffusion level based on magnetic flux, eddy currents, surface composition, local magnetic properties, and appearance inspection results. The feedback correction module 9 then correlates the diffusion level with motor operating data, demagnetization risk index, diffusion source layer parameters, and heat treatment parameters to generate feedback correction parameters, which are used for subsequent batch process corrections.

[0091] Through closed-loop compensation, zoned heat input, post-diffusion grading, and feedback correction in this embodiment, high-demagnetization-risk areas can receive timely recoating and localized heating when wetting is insufficient or edge diffusion is inadequate, while low-demagnetization-risk areas can be protected by cooling or thermal shielding when there is a risk of overheating or heavy rare earth migration. Post-diffusion detection and grading can match magnets with different diffusion effects to the corresponding motor assembly positions. The feedback correction module 9 can continuously optimize the diffusion execution parameter set for subsequent batches, including risk threshold parameters, diffusion source application amount, and heat treatment parameters, thereby improving batch diffusion consistency, reducing ineffective consumption of heavy rare earth elements, and improving the demagnetization resistance reliability of NdFeB magnets for new energy vehicle drive motors under high temperature, high speed, and weak magnetic conditions.

[0092] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principle of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A grain boundary diffusion treatment system for neodymium iron boron magnets used in new energy vehicle motors, characterized in that, include: The motor parameter acquisition module is used to acquire the structural parameters, operating condition parameters and magnet assembly position parameters of the drive motor, and form motor operating condition data. The partition modeling module, connected to the motor parameter acquisition module, is used to determine the demagnetization risk index of each evaluation area on the surface of the magnet to be processed based on the motor operating data, and to divide the first diffusion area, the second diffusion area, and the third diffusion area according to the demagnetization risk index, and generate a diffusion execution parameter set. The magnet attitude localization module, connected to the partition modeling module, is used to identify the actual attitude of the magnet to be processed and map each diffusion region to the actual surface of the magnet to be processed. A diffusion source application module, connected to a partition modeling module and a magnet attitude positioning module, is used to perform corresponding diffusion source processing according to the diffusion execution parameter set and the actual surface to form a first diffusion source layer, a second diffusion source layer and a third diffusion source layer. The diffusion source status detection module is connected to the diffusion source application module and is used to detect the diffusion source layer thickness and coverage status of each diffusion region and generate diffusion source status evaluation values. A closed-loop compensation control module is connected to the diffusion source status detection module and is used to generate compensation instructions based on the diffusion source status evaluation value. The partitioned thermal field grain boundary diffusion module connects the partitioned modeling module, the diffusion source state detection module, and the closed-loop compensation control module. It is used to perform partitioned grain boundary diffusion heat treatment according to the diffusion execution parameter set, the diffusion source state evaluation value, and the compensation command to obtain the diffused magnet. The diffusion post-diffusion detection and grading module is connected to the partitioned thermal field grain boundary diffusion module and is used to detect the diffused magnet and determine the diffusion level. The feedback correction module, which connects the post-diffusion detection and grading module and the partition modeling module, is used to correct the diffusion execution parameter set for subsequent batches based on the diffusion level.

2. The grain boundary diffusion treatment system for neodymium iron boron magnets for new energy vehicle motors according to claim 1, characterized in that, The partition modeling module includes: The evaluation area division unit is used to divide the surface of the magnet to be processed into multiple non-overlapping evaluation areas based on the motor operating data and the surface of the magnet to be processed. The risk parameter extraction unit, connected to the evaluation area division unit, is used to extract the corresponding temperature parameters, demagnetization field parameters, magnetization direction parameters, and boundary distance parameters based on the motor operating condition data and each of the evaluation areas. A demagnetization risk calculation unit, connected to the risk parameter extraction unit, is used to calculate the demagnetization risk index of each of the regions to be evaluated based on the temperature parameter, demagnetization field parameter, magnetization direction parameter, and boundary distance parameter. The partitioning determination unit, connected to the demagnetization risk calculation unit, is used to divide the corresponding area to be evaluated into a first diffusion area when the demagnetization risk index is greater than or equal to a first risk threshold, divide the corresponding area to be evaluated into a second diffusion area when the demagnetization risk index is less than the first risk threshold but greater than or equal to a second risk threshold, and divide the corresponding area to be evaluated into a third diffusion area when the demagnetization risk index is less than the second risk threshold. Wherein, the first risk threshold is greater than the second risk threshold.

3. The grain boundary diffusion treatment system for neodymium iron boron magnets for new energy vehicle motors according to claim 2, characterized in that, The partition modeling module also includes: The parameter mapping unit, connected to the partition determination unit, is used to generate corresponding diffusion execution parameters according to the first diffusion region, the second diffusion region and the third diffusion region, respectively, to form the diffusion execution parameter set; The diffusion execution parameter set includes risk threshold parameters, diffusion source layer parameters, and heat treatment parameters. The risk threshold parameters include a first risk threshold and a second risk threshold. The diffusion source layer parameters include diffusion source layer structure, heavy rare earth reinforcement layer thickness parameters, and diffusion source application amount. The heat treatment parameters include target wetting evaluation threshold, zoned thermal input parameters, and compensation triggering conditions. The thickness parameter of the heavy rare earth reinforced layer corresponding to the first diffusion region is greater than that of the heavy rare earth reinforced layer corresponding to the second diffusion region, and the thickness parameter of the heavy rare earth reinforced layer corresponding to the third diffusion region is zero.

4. The grain boundary diffusion treatment system for neodymium iron boron magnets for new energy vehicle motors according to claim 1, characterized in that, The magnet attitude positioning module includes: The attitude recognition unit is used to identify the end face, side face, corner, chamfer and air gap side surface of the magnet to be processed, and obtain magnet attitude data; An assembly direction recognition unit, connected to the attitude recognition unit, is used to determine the assembly direction of the magnet to be processed in the drive motor based on the motor operating condition data and the magnet attitude data. The partition mapping unit, connected to the assembly direction recognition unit, is used to map the first diffusion region, the second diffusion region, and the third diffusion region onto the actual surface of the magnet to be processed, based on the magnet attitude data, the assembly direction, and the first diffusion region, the second diffusion region, and the third diffusion region.

5. The grain boundary diffusion treatment system for neodymium iron boron magnets for new energy vehicle motors according to claim 3, characterized in that, The diffusion source application module includes: A diffusion source selection unit is used to select the diffusion source layer type for the corresponding diffusion region according to the diffusion source layer parameters. A localized application unit, connected to the diffusion source selection unit, is used to apply a first diffusion source layer comprising a wetting promotion layer, a first heavy rare earth strengthening layer, and a diffusion adjustment layer to the first diffusion region, a second diffusion source layer comprising a wetting promotion layer and a second heavy rare earth strengthening layer to the second diffusion region, and a third diffusion source layer to the third diffusion region, based on the diffusion source layer type and the actual surface of the magnet to be processed; wherein, the heavy rare earth content parameter of the second heavy rare earth strengthening layer is less than the heavy rare earth content parameter of the first heavy rare earth strengthening layer, and the third diffusion source layer is a grain boundary modification layer without a heavy rare earth strengthening layer. A layer thickness control unit, connected to the localized application unit, is used to control the diffusion source layer thickness of each diffusion region according to the diffusion source application amount.

6. The grain boundary diffusion treatment system for neodymium iron boron magnets for new energy vehicle motors according to claim 5, characterized in that, The diffusion source state detection module includes: The state acquisition unit is used to acquire the diffusion source layer thickness, coverage integrity, thickness uniformity and edge coverage of each diffusion region after the diffusion source is applied, and to acquire the melting and spreading degree of each diffusion region during the heating stage of the partition grain boundary diffusion heat treatment, so as to obtain diffusion source state data. The status evaluation unit, connected to the status acquisition unit, is used to generate a diffusion source status evaluation value for each diffusion region based on the diffusion source status data.

7. The grain boundary diffusion treatment system for neodymium iron boron magnets for new energy vehicle motors according to claim 6, characterized in that, The closed-loop compensation control module is also connected to the diffusion source application module. The closed-loop compensation control module is used to control the diffusion source application module to perform recoating according to the recoating instruction, and to control the partitioned thermal field grain boundary diffusion module to perform heat treatment compensation according to the heat treatment compensation instruction. The closed-loop compensation control module includes: The threshold comparison unit is used to compare the diffusion source state evaluation value of each diffusion region with the corresponding target wetting evaluation threshold to obtain the state comparison result. The compensation instruction generation unit, connected to the threshold comparison unit, is used to generate the recoating instruction and / or the heat treatment compensation instruction when the state comparison result meets the corresponding compensation triggering condition. The heat treatment compensation instructions include one or more of the following: local heat replenishment instructions, heat preservation correction instructions, secondary grain boundary diffusion instructions, and cooling protection instructions.

8. The grain boundary diffusion treatment system for neodymium iron boron magnets for new energy vehicle motors according to claim 7, characterized in that, The partitioned thermal field grain boundary diffusion module includes: An environmental control unit is used to provide a vacuum environment or a low-oxygen inert atmosphere environment for the magnet to be processed; The main heating unit is connected to the environmental control unit and is used to heat the magnet to be treated as a whole according to the heat treatment parameters. A partitioned heat input unit, connected to the main heating unit, is used to apply corresponding equivalent heat inputs to the first diffusion region, the second diffusion region, and the third diffusion region according to the partitioned heat input parameters and the heat treatment compensation instructions; wherein, the equivalent heat input corresponding to the first diffusion region is greater than the equivalent heat input corresponding to the second diffusion region, and the equivalent heat input corresponding to the second diffusion region is greater than or equal to the equivalent heat input corresponding to the third diffusion region; A cooling control unit, connected to the partitioned heat input unit, is used to cool the magnet after partitioned grain boundary diffusion heat treatment to obtain a diffused magnet.

9. The grain boundary diffusion treatment system for neodymium iron boron magnets for new energy vehicle motors according to claim 1, characterized in that, The post-diffusion detection and grading module includes: The post-diffusion detection unit is used to perform magnetic flux detection, eddy current detection, surface composition detection, local magnetic property detection, and appearance inspection on the diffused magnet to obtain post-diffusion detection data. A grade determination unit, connected to the post-diffusion detection unit, is used to generate a diffusion quality evaluation value based on the post-diffusion detection data. When the diffusion quality evaluation value is greater than or equal to a first grade threshold, the diffused magnet is determined to be a first-grade magnet. When the diffusion quality evaluation value is less than the first grade threshold but greater than or equal to a second grade threshold, the diffused magnet is determined to be a second-grade magnet. When the diffusion quality evaluation value is less than the second grade threshold, the diffused magnet is determined to be a third-grade magnet. Wherein, the threshold of the first level is greater than the threshold of the second level.

10. The grain boundary diffusion treatment system for neodymium iron boron magnets for new energy vehicle motors according to claim 3, characterized in that, The feedback correction module is also connected to the diffusion source application module and the partitioned thermal field grain boundary diffusion module, and the feedback correction module includes: The result association unit is used to associate the diffusion level with the motor operating data, the demagnetization risk index, the diffusion source layer parameters, and the heat treatment parameters to obtain batch association data. A parameter correction unit, connected to the result association unit, is used to generate feedback correction parameters based on the batch association data. The feedback correction parameters are used to correct one or more parameters in the diffusion execution parameter set of magnets to be processed in subsequent batches that have the same magnet assembly position parameters or motor condition data that meet preset working condition matching conditions. The one or more parameters in the diffusion execution parameter set include one or more of a first risk threshold, a second risk threshold, diffusion source layer parameters, and heat treatment parameters.

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