Manufacturing process of radial magnetic flux cylinder type motor iron core

Abstract

The invention discloses a manufacturing process of a radial magnetic flux cylinder type motor iron core, and particularly relates to the technical field of motor iron core manufacturing, and the manufacturing process comprises the steps: employing magnetron sputtering to construct a gradient insulation coating on the surface of a nanocrystalline strip, and enabling the gradient insulation coating and silicon steel sheets to be alternately laminated to form a magnetic conduction-bearing composite structure; a yoke bionic honeycomb runner and a tooth magnetic barrier groove are machined through femtosecond laser, and magnetothermal coupling optimization is achieved; multidirectional progressive stamping forming is conducted in the pulsed magnetic field environment, and grain directional arrangement and interface metallurgical bonding are achieved in combination with femtosecond laser micro-connection; the integrated eddy current detection system regulates and controls press fitting parameters in real time, and stress regulation and control are completed through two-stage microwave annealing and ion beam treatment. According to the method, the magnetic circuit efficiency and the heat dissipation performance of the iron core are effectively improved, through material-structure-process collaborative innovation, the problems of magnetothermal imbalance, grain disorder, assembly accumulative errors and the like in traditional manufacturing are solved, and the operation stability and the service life reliability of the iron core under the high-frequency and high-load working condition are remarkably improved.

Description

Technical Field

[0001] The present invention relates to the field of motor iron core processing, and in particular to a manufacturing process of a radial flux cylinder type motor iron core. Background Art

[0002] Compared to traditional axial magnetic motors, radial flux cylindrical motors, with their radially distributed magnetic circuits, place higher demands on core manufacturing. Traditional axial motor cores are typically formed by laminating homogeneous silicon steel sheets. However, radial structures require efficient three-dimensional magnetic flux conduction within a limited space. This requires the core material to possess gradient magnetic conductivity and integrate efficient heat dissipation channels within the yoke area. Existing manufacturing processes typically utilize a single material, stamping and laminating, making it difficult to reconcile the conflicting relationship between magnetic flux density distribution and mechanical strength.

[0003] The current preparation technology has the following core defects: First, the isotropic characteristics of traditional laminated materials lead to the coexistence of magnetic saturation in the teeth and hysteresis loss in the yoke; second, the grain orientation disorder caused by the stamping process weakens the material's magnetic permeability advantage; third, the heat-affected zone generated by conventional laser welding causes local magnetic circuit distortion; in addition, the assembly process lacks a real-time compensation mechanism for microscopic deformation, resulting in a significant cumulative effect of the stacking gap; finally, traditional annealing processes make it difficult to simultaneously optimize the material lattice structure and residual stress distribution.

[0004] In view of this, the present invention provides a process for manufacturing a radial flux cylindrical motor core. Summary of the Invention

[0005] The main purpose of the present invention is to provide a manufacturing process for radial flux cylindrical motor cores, which achieves a synergistic improvement in the core magnetic circuit efficiency, heat dissipation performance and manufacturing precision through the systematic integration of gradient material composite technology, bionic magnetothermal coupling structure design and femtosecond laser micro-connection technology.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] A manufacturing process for a radial flux cylindrical motor core, the specific steps are as follows:

[0008] Step 1: Using a dual-target magnetron sputtering process, a 1-2 μm thick Al2O3 / TiN gradient composite coating is deposited on the surface of a 0.05-0.15 mm thick nanocrystalline ribbon. At the same time, a 0.5-1 μm thick phosphate insulation layer is formed on the surface of a 0.3-0.4 mm thick silicon steel sheet. The nanocrystalline ribbons and silicon steel sheets are alternately laminated in a 1:3 thickness ratio. A single laminate unit contains 12 nanocrystalline ribbons and 36 silicon steel sheets.

[0009] Step 2: Use a power density of 18W / cm 2The femtosecond laser cutting system performs bionic magnetothermal coupling structure processing on the laminated unit, forming a 1.2mm diameter regular hexagonal axial flow channel in the yoke area, with the channel wall thickness maintained at 0.25mm. The tooth area retains a complete magnetic circuit and a 0.3mm deep magnetic barrier groove is opened on the tooth top.

[0010] Step 3: Multi-directional progressive stamping is performed in a 3-3.5T pulsed magnetic field environment. The magnetic field direction forms a 52-degree angle with the tooth axis. The stamping speed is controlled at 15mm / s. During the holding stage, a pressure of 25MPa is applied and maintained for 10 seconds.

[0011] Step 4: A femtosecond laser with a wavelength of 1030nm is used to selectively micro-connect the stack. The focused spot diameter is 18μm, forming an array of micro-weld points with an interval of 1.5 to 1.8mm at the tooth root. The single-point action time is 2.5ms, and the penetration depth reaches 20μm.

[0012] Step 5: During the assembly process, an eddy current detection system with a resolution of 1μm is integrated, and the probe spacing is set to 0.6mm. The press force is adjusted with real-time feedback and the pressure fluctuation is controlled within the range of ±15N.

[0013] Step 6: Perform two-stage microwave annealing under argon protection: in the first stage, heat the sample to 720°C at a rate of 50°C / s and hold for 25 minutes; in the second stage, cool the sample to 450°C at a rate of 20°C / s and hold for 20 minutes;

[0014] Step 7: After air cooling to room temperature, ion beam surface treatment is used to eliminate residual stress, and finally a radial flux cylindrical motor core is obtained.

[0015] Preferably, the mass ratio of Al2O3 to TiN in the gradient composite coating is (3-5):1.

[0016] Preferably, the wall surface roughness Ra value of the regular hexagonal axial flow channel is controlled within a range of 0.8-1.2 μm.

[0017] Preferably, the friction coefficient between the mold and the material during the multi-directional progressive stamping process is controlled at 0.08-0.12.

[0018] Preferably, the micro-weld spot array is staggeredly distributed at the tooth root, and the axial spacing between adjacent weld spots is 1.2 mm to 1.8 mm.

[0019] Preferably, the excitation frequency of the eddy current detection system is set in the range of 2.5-3.2 MHz.

[0020] Preferably, the power density of the microwave annealing in the first stage is 12-15 W / cm 3 .

[0021] Preferably, the beam energy density of the ion beam surface treatment is 25 to 30 J / cm 2 .

[0022] Preferably, the beam energy density of the ion beam surface treatment is 25 to 30 J / cm 2 .

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The present invention achieves the coordinated optimization of the core magnetic circuit conduction efficiency and mechanical bearing capacity through gradient material composite technology. The alternating laminated structure of nanocrystalline strips and silicon steel sheets enables the material's magnetic permeability characteristics to accurately match the three-dimensional magnetic flux distribution requirements. The bionic honeycomb flow channel design maintains the integrity of the magnetic circuit while constructing a functional integrated channel for axial heat dissipation and radial magnetic conduction, effectively balancing the contradiction between electromagnetic loss and heat accumulation under high magnetic density conditions. The femtosecond laser micro-connection process not only achieves reliable consolidation of the laminations, but also avoids the destruction of the magnetic domain structure caused by traditional welding. Combined with the pulsed magnetic field directional forming technology, it significantly improves the consistency of the material grain orientation. The combined application of microwave annealing and ion beam treatment achieves gradient control of the material microstructure while eliminating residual stress. Combined with the precision assembly system with real-time feedback, it ensures the dimensional stability and performance reproducibility of the overall structure of the core. DETAILED DESCRIPTION

[0025] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below in conjunction with specific implementation methods.

[0026] This paper provides a manufacturing process for radial flux cylindrical motor cores. Initially, this process involved reverse engineering a failure case involving a drive motor for a new energy vehicle. Disassembly revealed that conventional radial flux cores exhibited dual failure characteristics under sustained high load conditions: magnetic saturation in the teeth and thermal fatigue in the yoke. This phenomenon reveals the limited adaptability of existing homogeneous cores in three-dimensional magnetothermal coupling.

[0027] Based on the concept of magnetothermal collaborative design, the research team proposed a gradient material composite concept. Using transmission electron microscopy to observe the evolution of the material's microstructure under different operating conditions, they found that nanocrystalline ribbons exhibit excellent domain wall migration characteristics in alternating magnetic fields, while silicon steel sheets exhibit better mechanical stability in static magnetic fields. This provides a theoretical basis for establishing a spatial mapping relationship between material properties and magnetic flux paths.

[0028] During the structural optimization phase, inspired by the mechanical properties of honeycomb structures, an attempt was made to incorporate bionic principles into the magnetic circuit design. Finite element simulation revealed that the regular hexagonal flow channels exhibited a unique balance between axial heat dissipation efficiency and radial magnetic resistance. Furthermore, a topology optimization algorithm was used to determine the optimal distribution pattern for the magnetic barrier slots, allowing the main magnetic flux path to naturally avoid high-stress areas.

[0029] During process development, the heat-affected zone (HAZ) problem in traditional laser welding became a bottleneck. By comparing the effects of lasers with different pulse widths, they discovered that the non-melting micro-joining properties of femtosecond lasers effectively preserve the material's magnetic properties. Simultaneously developed pulsed magnetic field-assisted forming technology successfully addressed the issue of grain orientation disorder during laminate stamping of gradient materials.

[0030] Based on this, the present invention is further disclosed below in conjunction with specific embodiments and comparative examples.

[0031] Example 1

[0032] This embodiment discloses a process for manufacturing a radial flux cylindrical motor core, and the specific steps are as follows:

[0033] Step 1: A dual-target magnetron sputtering process is used to deposit a 1.2μm thick Al2O3 / TiN gradient composite coating on the surface of a 0.1mm thick nanocrystalline ribbon. The mass ratio of Al2O3 to TiN in the gradient composite coating is 3:1. At the same time, a 0.8μm phosphate insulation layer is formed on the surface of a 0.35mm silicon steel sheet. The nanocrystalline ribbons and silicon steel sheets are alternately laminated at a thickness ratio of 1:3. A single laminate unit contains 12 nanocrystalline ribbons and 36 silicon steel sheets.

[0034] Step 2: Use a power density of 18W / cm 2 The femtosecond laser cutting system performs bionic magnetothermal coupling structure processing on the laminated unit, forming a 1.2mm diameter regular hexagonal axial flow channel in the yoke area. The wall roughness Ra value of the regular hexagonal axial flow channel is controlled at 0.8-1.2μm, and the flow channel wall thickness is maintained at 0.25mm. The tooth area retains a complete magnetic circuit and a 0.3mm deep magnetic barrier groove is opened on the tooth top; the bottom chamfer radius of the magnetic barrier groove is 0.05mm.

[0035] Step 3: Multi-directional progressive stamping is performed in a 3.2T pulsed magnetic field environment. During the multi-directional progressive stamping process, the friction coefficient between the mold and the material is controlled at 0.08, the magnetic field direction forms an angle of 52 degrees with the tooth axis, the stamping speed is controlled at 15mm / s, and a pressure of 25MPa is applied during the holding stage and maintained for 10 seconds;

[0036] Step 4: A femtosecond laser with a wavelength of 1030nm is used to selectively micro-connect the stack. The micro-weld array is staggered at the tooth root, with an axial spacing of 1.2mm between adjacent welds. The focused spot diameter is 18μm, forming a micro-weld array with a spacing of 1.8mm at the tooth root. The single-point action time is 2.5ms, and the penetration depth reaches 20μm.

[0037] Step 5: During the assembly process, an eddy current detection system with a resolution of 1μm is integrated. The excitation frequency of the eddy current detection system is set within the range of 2.5MHz, the probe spacing is set to 0.6mm, and the press force is adjusted in real time with feedback to control the pressure fluctuation within the range of ±15N.

[0038] Step 6: Two-stage microwave annealing was performed under argon protection. In the first stage, the temperature was raised to 720°C at a rate of 50°C / s and kept at this temperature for 25 minutes. The power density of the microwave annealing was 12 W / cm 3 ; In the second stage, the temperature was lowered to 450℃ at a rate of 20℃ / s and maintained for 20 minutes;

[0039] Step 7: After air cooling to room temperature, ion beam surface treatment is used to eliminate residual stress. The beam energy density of the ion beam surface treatment is 25J / cm 2 , and finally obtain the radial flux cylindrical motor core.

[0040] Example 2

[0041] The manufacturing process of the radial flux cylindrical motor core disclosed in this embodiment has the following specific steps:

[0042] Step 1: A 1μm thick Al2O3 / TiN gradient composite coating is deposited on the surface of a 0.05mm thick nanocrystalline ribbon using a dual-target magnetron sputtering process. The gradient composite coating has an Al2O3 to TiN mass ratio of 4:1. Simultaneously, a 0.5μm phosphate insulation layer is formed on the surface of a 0.3mm thick silicon steel sheet. The nanocrystalline ribbons and silicon steel sheets are alternately laminated at a thickness ratio of 1:3. A single laminate unit contains 12 nanocrystalline ribbons and 36 silicon steel sheets.

[0043] Step 2: Use a power density of 18W / cm 2 The femtosecond laser cutting system performs bionic magnetothermal coupling structure processing on the laminated unit, forming a 1.2mm diameter regular hexagonal axial flow channel in the yoke area. The wall roughness Ra value of the regular hexagonal axial flow channel is controlled at 0.9μm, and the flow channel wall thickness is maintained at 0.25mm. The tooth area retains a complete magnetic circuit and a 0.3mm deep magnetic barrier groove is opened on the tooth top; the bottom chamfer radius of the magnetic barrier groove is 0.06mm.

[0044] Step 3: Multi-directional progressive stamping is performed in a 3T pulsed magnetic field environment. During the multi-directional progressive stamping process, the friction coefficient between the mold and the material is controlled at 0.09, the magnetic field direction forms an angle of 52 degrees with the tooth axis, the stamping speed is controlled at 15 mm / s, and a pressure of 25 MPa is applied during the holding stage and maintained for 10 seconds.

[0045] Step 4: A femtosecond laser with a wavelength of 1030nm is used to selectively micro-connect the stack. The micro-weld array is staggered at the tooth root, with an axial spacing of 1.4mm between adjacent welds. The focused spot diameter is 18μm, forming a micro-weld array with a spacing of 1.8mm at the tooth root. The single-point action time is 2.5ms, and the penetration depth reaches 20μm.

[0046] Step 5: During the assembly process, an eddy current detection system with a resolution of 1μm is integrated. The excitation frequency of the eddy current detection system is set within the range of 2.7MHz, the probe spacing is set to 0.6mm, and the press force is adjusted in real time with feedback to control the pressure fluctuation within the range of ±15N.

[0047] Step 6: Two-stage microwave annealing was performed under argon protection. In the first stage, the temperature was raised to 720°C at a rate of 50°C / s and kept at this temperature for 25 minutes. The power density of the microwave annealing was 12 W / cm 3 ; In the second stage, the temperature was lowered to 450℃ at a rate of 20℃ / s and maintained for 20 minutes;

[0048] Step 7: After air cooling to room temperature, ion beam surface treatment is used to eliminate residual stress. The beam energy density of ion beam surface treatment is 25-30 J / cm 2 , and finally obtain the radial flux cylindrical motor core.

[0049] Example 3

[0050] The manufacturing process of the radial flux cylindrical motor core disclosed in this embodiment has the following specific steps:

[0051] Step 1: A 2μm thick Al2O3 / TiN gradient composite coating is deposited on the surface of a 0.15mm thick nanocrystalline ribbon using a dual-target magnetron sputtering process. The gradient composite coating has an Al2O3 to TiN mass ratio of 5:1. Simultaneously, a 1μm thick phosphate insulation layer is formed on the surface of a 0.4mm thick silicon steel sheet. The nanocrystalline ribbons and silicon steel sheets are alternately laminated at a thickness ratio of 1:3. A single laminate unit contains 12 nanocrystalline ribbons and 36 silicon steel sheets.

[0052] Step 2: Use a power density of 18W / cm 2The femtosecond laser cutting system performs bionic magnetothermal coupling structure processing on the laminated unit, forming a 1.2mm diameter regular hexagonal axial flow channel in the yoke area. The wall roughness Ra value of the regular hexagonal axial flow channel is controlled at 1μm, and the flow channel wall thickness is maintained at 0.25mm. The tooth area retains a complete magnetic circuit and a 0.3mm deep magnetic barrier groove is opened at the tooth top; the bottom chamfer radius of the magnetic barrier groove is 0.06mm.

[0053] Step 3: Multi-directional progressive stamping is performed in a 3.5T pulsed magnetic field environment. During the multi-directional progressive stamping process, the friction coefficient between the mold and the material is controlled at 0.08-0.12, the magnetic field direction forms an angle of 52 degrees with the tooth axis, the stamping speed is controlled at 15mm / s, and a pressure of 25MPa is applied during the holding stage and maintained for 10 seconds;

[0054] Step 4: A femtosecond laser with a wavelength of 1030nm is used to selectively micro-connect the stack. The micro-weld array is staggered at the tooth root, with an axial spacing of 1.8mm between adjacent welds. The focused spot diameter is 18μm, forming a micro-weld array with a spacing of 1.8mm at the tooth root. The single-point action time is 2.5ms, and the penetration depth reaches 20μm.

[0055] Step 5: During the assembly process, an eddy current detection system with a resolution of 1μm is integrated. The excitation frequency of the eddy current detection system is set within the range of 3.2MHz, the probe spacing is set to 0.6mm, and the press force is adjusted in real time with feedback to control the pressure fluctuation within the range of ±15N.

[0056] Step 6: Two-stage microwave annealing was performed under argon protection. In the first stage, the temperature was raised to 720°C at a rate of 50°C / s and kept at this temperature for 25 minutes. The power density of the microwave annealing was 15W / cm 3 ; In the second stage, the temperature was lowered to 450℃ at a rate of 20℃ / s and maintained for 20 minutes;

[0057] Step 7: After air cooling to room temperature, ion beam surface treatment is used to eliminate residual stress. The beam energy density of the ion beam surface treatment is 30J / cm 2 , and finally obtain the radial flux cylindrical motor core.

[0058] Example 4

[0059] The manufacturing process of the radial flux cylindrical motor core disclosed in this embodiment has the following specific steps:

[0060] Step 1: A dual-target magnetron sputtering process is used to deposit a 1.8μm thick Al2O3 / TiN gradient composite coating on the surface of a 0.13mm thick nanocrystalline ribbon. The mass ratio of Al2O3 to TiN in the gradient composite coating is 3:1. At the same time, a 0.8μm phosphate insulation layer is formed on the surface of a 0.37mm silicon steel sheet. The nanocrystalline ribbons and silicon steel sheets are alternately stacked at a thickness ratio of 1:3. A single stacking unit contains 12 nanocrystalline ribbons and 36 silicon steel sheets.

[0061] Step 2: Use a power density of 18W / cm 2 The femtosecond laser cutting system performs bionic magnetothermal coupling structure processing on the laminated unit, forming a 1.2mm diameter regular hexagonal axial flow channel in the yoke area. The wall roughness Ra value of the regular hexagonal axial flow channel is controlled at 1μm, and the flow channel wall thickness is maintained at 0.25mm. The tooth area retains a complete magnetic circuit and a 0.3mm deep magnetic barrier groove is opened on the tooth top; the bottom chamfer radius of the magnetic barrier groove is 0.08mm.

[0062] Step 3: Multi-directional progressive stamping is performed in a 3.4T pulsed magnetic field environment. During the multi-directional progressive stamping process, the friction coefficient between the mold and the material is controlled at 0.12, the magnetic field direction forms an angle of 52 degrees with the tooth axis, the stamping speed is controlled at 15mm / s, and a pressure of 25MPa is applied during the holding stage and maintained for 10 seconds;

[0063] Step 4: A femtosecond laser with a wavelength of 1030nm is used to selectively micro-connect the stack. The micro-weld array is staggered at the tooth root, with an axial spacing of 1.8mm between adjacent welds. The focused spot diameter is 18μm, forming a micro-weld array with a spacing of 1.8mm at the tooth root. The single-point action time is 2.5ms, and the penetration depth reaches 20μm.

[0064] Step 5: During the assembly process, an eddy current detection system with a resolution of 1μm is integrated. The excitation frequency of the eddy current detection system is set within the range of 3.1MHz, the probe spacing is set to 0.6mm, and the press force is adjusted in real time with feedback to control the pressure fluctuation within the range of ±15N.

[0065] Step 6: Two-stage microwave annealing was performed under argon protection. In the first stage, the temperature was raised to 720°C at a rate of 50°C / s and kept at this temperature for 25 minutes. The power density of the microwave annealing was 14 W / cm 3 ; In the second stage, the temperature was lowered to 450℃ at a rate of 20℃ / s and maintained for 20 minutes;

[0066] Step 7: After air cooling to room temperature, ion beam surface treatment is used to eliminate residual stress. The beam energy density of the ion beam surface treatment is 28J / cm 2 , and finally obtain the radial flux cylindrical motor core.

[0067] Example 5

[0068] The manufacturing process of the radial flux cylindrical motor core disclosed in this embodiment has the following specific steps:

[0069] Step 1: A dual-target magnetron sputtering process is used to deposit a 1.2 μm thick Al2O3 / TiN gradient composite coating on the surface of a 0.07 mm thick nanocrystalline ribbon. The mass ratio of Al2O3 to TiN in the gradient composite coating is 4:1. At the same time, a 0.6 μm phosphate insulation layer is formed on the surface of a 0.32 mm thick silicon steel sheet. The nanocrystalline ribbons and silicon steel sheets are alternately laminated at a thickness ratio of 1:3. A single laminate unit contains 12 nanocrystalline ribbons and 36 silicon steel sheets.

[0070] Step 2: Use a power density of 18W / cm 2 The femtosecond laser cutting system performs bionic magnetothermal coupling structure processing on the laminated unit, forming a 1.2mm diameter regular hexagonal axial flow channel in the yoke area. The wall roughness Ra value of the regular hexagonal axial flow channel is controlled at 0.9μm, and the flow channel wall thickness is maintained at 0.25mm. The tooth area retains a complete magnetic circuit and a 0.3mm deep magnetic barrier groove is opened on the tooth top; the bottom chamfer radius of the magnetic barrier groove is 0.07mm.

[0071] Step 3: Multi-directional progressive stamping is performed in a 3.1T pulsed magnetic field environment. During the multi-directional progressive stamping process, the friction coefficient between the mold and the material is controlled at 0.11, the magnetic field direction forms an angle of 52 degrees with the tooth axis, the stamping speed is controlled at 15mm / s, and a pressure of 25MPa is applied during the holding stage and maintained for 10 seconds;

[0072] Step 4: A femtosecond laser with a wavelength of 1030nm is used to selectively micro-connect the stack. The micro-weld array is staggered at the tooth root, with an axial spacing of 1.2mm between adjacent welds. The focused spot diameter is 18μm, forming a micro-weld array with a spacing of 1.8mm at the tooth root. The single-point action time is 2.5ms, and the penetration depth reaches 20μm.

[0073] Step 5: During the assembly process, an eddy current detection system with a resolution of 1μm is integrated. The excitation frequency of the eddy current detection system is set within the range of 2.7MHz, the probe spacing is set to 0.6mm, and the press force is adjusted in real time with feedback to control the pressure fluctuation within the range of ±15N.

[0074] Step 6: Two-stage microwave annealing was performed under argon protection. In the first stage, the temperature was raised to 720°C at a rate of 50°C / s and kept at this temperature for 25 minutes. The power density of the microwave annealing was 15W / cm 3 ; In the second stage, the temperature was lowered to 450℃ at a rate of 20℃ / s and maintained for 20 minutes;

[0075] Step 7: After air cooling to room temperature, ion beam surface treatment is used to eliminate residual stress. The beam energy density of the ion beam surface treatment is 27J / cm 2 , and finally obtain the radial flux cylindrical motor core.

[0076] Comparative Example 1

[0077] The difference between this comparative example and Example 1 is:

[0078] In step 1, the gradient composite coating design was eliminated. Instead, a single 0.8 μm phosphate insulating layer was used for both the nanocrystalline strip and the silicon steel sheet, and the stacking ratio was changed to a 1:1 alternating layer of equal thickness. In step 6, conventional resistance furnace annealing was performed, with the temperature being increased to 750°C at a rate of 10°C / s, held for 60 minutes, and then naturally cooled.

[0079] The remaining step parameters are exactly the same as those in Example 1.

[0080] Comparative Example 2

[0081] The difference between this comparative example and Example 1 is:

[0082] In step 4, continuous wave laser welding was used, with the spot diameter increased to 50 μm, the weld point spacing increased to 3 mm, and the single-point action time extended to 10 ms. In step 5, the eddy current detection system was eliminated, and a fixed pressure of 80 N was used for press-fitting. In step 2, the flow channel was changed to a traditional circular cross-section, with a diameter increased to 1.5 mm.

[0083] The remaining step parameters remain the same as in Example 1.

[0084] The samples prepared in Examples 1-5 and Comparative Examples 1-2 were subjected to the following tests. The test results are shown in Table 1.

[0085] 1. Magnetic permeability anisotropy test

[0086] Test basis: IEC60404-8 "Magnetic materials Part 8: Specifications for individual materials".

[0087] Test steps: (1) Prepare a 30 mm × 30 mm standard sample and cut it in the radial, axial, and tangential directions; (2) Use a BH analyzer to measure the magnetic permeability in an isotropic manner at a magnetic field strength of 1.5 T; (3) Calculate the anisotropy coefficient K = μ 径向 / (μ 轴向 +μ 切向 ).

[0088] 2. Continuous temperature rise test

[0089] Test basis: GB / T21221-2007 "Test method for temperature rise of rotating electrical machines".

[0090] Test steps: (1) Build a closed test environment with an initial temperature of 25±1°C; (2) Apply a rated current density of 6A / mm 2 The operation lasts for 2 hours; (3) the infrared thermal imager records the temperature extremes of the tooth top, yoke, and flow channel wall.

[0091] 3. Overlay Gap Detection

[0092] Test basis: JB / T10314-2013 "Technical Requirements for Stacked Motor Cores".

[0093] Test steps: (1) Use a laser confocal scanner to select 10 test surfaces at equal distances along the axial direction; (2) Measure the maximum gap value between each stack and calculate the standard deviation; (3) Count the proportion of abnormal points with gaps exceeding 5μm.

[0094] Table 1. Performance test results of samples of Examples 1-5 and Comparative Examples 1-3.

[0095]

[0096] It can be seen from the test data that the performance of comparative example 1 in terms of anisotropy coefficient and temperature rise control is significantly deteriorated. Its anisotropy coefficient of 1.12 is due to the intensification of the isotropic characteristics of the material after the gradient composite coating is removed. At the same time, the conventional annealing process fails to effectively control the grain orientation, resulting in a decrease in the efficiency of magnetic circuit conduction. The excessive temperature rise of 58.4K is due to the fact that a single material cannot achieve zoning optimization of magnetothermal performance, and the heat accumulation in the yoke cannot be effectively channeled through the homogeneous structure. The average gap of 12.7μm and the proportion of abnormal points of 18.6% reveal that in the absence of a real-time detection feedback mechanism, the traditional press-fitting process is difficult to control the cumulative effect of microscopic deformation.

[0097] Although Comparative Example 2 utilizes some advanced processes, the degradation of key parameters leads to performance degradation. The anisotropy coefficient of 1.24 indicates that the heat-affected zone generated by continuous laser welding destroys the material's magnetic domain structure, while the circular flow channel's temperature rise of 54.7K confirms that its heat dissipation efficiency is lower than that of the bionic structure. The average gap of 9.8μm and the 9.3% abnormal point ratio reflect that the gap caused by the elastic recovery of the material cannot be effectively compensated under the fixed press force mode, especially when irreversible deformation occurs during the stamping stress release phase.

[0098] The data from the examples demonstrates overall stability and superiority. An anisotropy coefficient of 1.78-1.85 demonstrates the synergistic effect of the gradient material and pulsed magnetic field on grain orientation. The temperature rise range of 36.2-38.1K demonstrates the efficient heat dissipation of the biomimetic flow channel. Furthermore, the gap control accuracy of 3.2-4.1μm demonstrates that femtosecond laser microjoining technology increases interfacial bonding strength to three times that of traditional processes. The percentage of abnormal points is consistently below 1.5%, confirming that the real-time detection system narrows the fluctuation tolerance of the assembly process.

[0099] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A process for manufacturing a radial flux cylindrical motor core, characterized in that: The specific steps are as follows: Step 1: Using a dual-target magnetron sputtering process, a 1-2 μm thick Al2O3 / TiN gradient composite coating is deposited on the surface of a 0.05-0.15 mm thick nanocrystalline ribbon. At the same time, a 0.5-1 μm thick phosphate insulation layer is formed on the surface of a 0.3-0.4 mm thick silicon steel sheet. The nanocrystalline ribbons and silicon steel sheets are alternately laminated in a 1:3 thickness ratio. A single laminate unit contains 12 nanocrystalline ribbons and 36 silicon steel sheets. Step 2: Use a power density of 18W / cm 2 The femtosecond laser cutting system performs bionic magnetothermal coupling structure processing on the laminated unit, forming a 1.2mm diameter regular hexagonal axial flow channel in the yoke area, with the channel wall thickness maintained at 0.25mm. The tooth area retains a complete magnetic circuit and a 0.3mm deep magnetic barrier groove is opened on the tooth top. Step 3: Multi-directional progressive stamping is performed in a 3-3.5T pulsed magnetic field environment. The magnetic field direction forms a 52-degree angle with the tooth axis. The stamping speed is controlled at 15mm / s. During the holding stage, a pressure of 25MPa is applied and maintained for 10 seconds. Step 4: A femtosecond laser with a wavelength of 1030nm is used to selectively micro-connect the stack. The focused spot diameter is 18μm, forming an array of micro-weld points with an interval of 1.5 to 1.8mm at the tooth root. The single-point action time is 2.5ms, and the penetration depth reaches 20μm. Step 5: During the assembly process, an eddy current detection system with a resolution of 1μm is integrated, and the probe spacing is set to 0.6mm. The press force is adjusted with real-time feedback and the pressure fluctuation is controlled within the range of ±15N. Step 6: Perform two-stage microwave annealing under argon protection: in the first stage, heat the sample to 720°C at a rate of 50°C / s and hold for 25 minutes; in the second stage, cool the sample to 450°C at a rate of 20°C / s and hold for 20 minutes; Step 7: After air cooling to room temperature, ion beam surface treatment is used to eliminate residual stress, and finally a radial flux cylindrical motor core is obtained.

2. The manufacturing process of the radial flux cylindrical motor core according to claim 1, characterized in that: The mass ratio of Al2O3 to TiN in the gradient composite coating is (3-5):

1.

3. The manufacturing process of the radial flux cylindrical motor core according to claim 1, characterized in that: The wall surface roughness Ra value of the regular hexagonal axial flow channel is controlled within a range of 0.8-1.2 μm.

4. The manufacturing process of the radial flux cylindrical motor core according to claim 1, characterized in that: During the multi-directional progressive stamping process, the friction coefficient between the mold and the material is controlled at 0.08-0.

12.

5. The manufacturing process of the radial flux cylindrical motor core according to claim 1, characterized in that: The micro-weld spot array is staggeredly distributed at the tooth root, and the axial spacing between adjacent weld spots is 1.2 mm to 1.8 mm.

6. The manufacturing process of the radial flux cylindrical motor core according to claim 1, characterized in that: The excitation frequency of the eddy current detection system is set in the range of 2.5-3.2 MHz.

7. The manufacturing process of the radial flux cylindrical motor core according to claim 1, characterized in that: The power density of microwave annealing in the first stage is 12-15 W / cm 3 .

8. The manufacturing process of the radial flux cylindrical motor core according to claim 1, characterized in that: The beam energy density of the ion beam surface treatment is 25 to 30 J / cm 2 .

9. The manufacturing process of the radial flux cylindrical motor core according to claim 1, characterized in that: The chamfer radius of the bottom of the magnetic barrier groove is 0.05mm to 0.08mm.

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