A design method and system for self-riveting fasteners of motor laminations

Abstract

This invention provides a design method and system for self-riveting fasteners on motor laminations. It determines the basic geometric structure of the boss-groove matching mechanism with inclined sidewalls for the self-riveting fasteners, designs the inclination angle α between the sidewall of the fastener and the normal to the lamination plane, and changes the contact area and stress distribution during riveting by adjusting the inclination angle α. Based on a preset riveting force threshold, it performs riveting force simulation and physical testing on self-riveting fasteners corresponding to different inclination angles α, ultimately determining the optimal range of inclination angle α that satisfies the preset riveting force threshold. Using this invention, the riveting force of self-riveting fasteners on motor laminations is significantly improved without increasing the number and size of fasteners or reducing the material utilization rate of the laminations, solving the problems of lamination loosening and misalignment caused by insufficient riveting force in traditional fasteners.

Description

Technical Field

[0001] This invention relates to the field of motor manufacturing technology, and in particular to a design method and system for self-riveting fastening points of motor laminations. Background Technology

[0002] The motor core is the core magnetic circuit and structural component of the motor. It is usually made of multiple silicon steel laminations stacked and riveted together using self-riveting fasteners. The riveting force of the fasteners directly determines the overall mechanical strength and operational stability of the core. If the riveting force is insufficient, the motor is prone to lamination loosening, axial movement, and circumferential misalignment under high-speed rotation, frequent start-stop, or load fluctuation conditions. This can disrupt the uniformity of the air gap, deteriorate the dynamic balance performance, and generate severe vibration and abnormal noise. In severe cases, it can even lead to fatal failures such as winding insulation wear and rotor rubbing.

[0003] Currently, the industry mainly adopts three types of solutions to address the problem of insufficient riveting force of self-riveting points on motor laminations: The first type is to increase the number of points to improve the overall riveting strength by distributing the force at multiple points. However, this method will significantly increase the scrap area of ​​the laminations, reduce the utilization rate of silicon steel materials, and increase the processing complexity and manufacturing cost of the die. The second type is to increase the overall size of the points to improve the riveting force by expanding the interlocking area. However, this method will exacerbate the magnetic circuit segmentation of the laminations, reduce the magnetic permeability of the iron core, and increase the iron loss of the motor. The third type is to increase the pressing force during the lamination process to improve the interlocking strength by increasing the plastic deformation of the points. However, this method will significantly accelerate the wear of the die punch and die, shorten the service life of the die, and easily cause the laminations to warp and deform, affecting the lamination coefficient of the iron core.

[0004] Furthermore, existing self-riveting fasteners mostly employ rectangular, circular, or trapezoidal structures with fixed angles. There is a lack of systematic research on the quantitative relationship between the sidewall inclination angle of the fastener and the riveting force. This makes it impossible to achieve optimal riveting force through precise angle parameter design, resulting in a significant reliance on experience and guesswork in fastener design. It is difficult to simultaneously address the multiple requirements of riveting force, material utilization, and die life. Therefore, how to effectively improve the riveting force of self-riveting fasteners for motor laminations without sacrificing material utilization, affecting motor magnetic performance, or shortening die life has become a pressing technical challenge for the industry. Summary of the Invention

[0005] Based on this, the present invention provides a design method and system for self-riveting fasteners of motor laminations that achieves precise improvement in riveting force by optimizing the inclination angle α of the fastener sidewall, thereby solving the problem of insufficient riveting force and difficulty in achieving comprehensive performance of self-riveting fasteners in the prior art.

[0006] In a first aspect, the present invention provides a method for designing self-riveting fasteners for motor laminations, comprising the following steps:

[0007] The basic geometric structure of the self-riveting fastening point of the motor lamination is determined, wherein the basic geometric structure is a boss-groove matching structure with inclined sidewalls;

[0008] Design the inclination angle α between the sidewall of the self-riveting fastener and the normal to the plane of the punch, and change the engagement contact area and stress distribution of the fastener during riveting by adjusting the size of the inclination angle α.

[0009] Based on the preset riveting force threshold, the riveting force of the self-riveting points corresponding to different tilt angles α is simulated and tested in practice.

[0010] Based on simulation and test results, the optimal range of tilt angle α that satisfies the preset riveting force threshold was determined, and the design of the self-riveting fastener of the motor lamination was completed.

[0011] As a further improvement to the technical solution of the present invention, the boss-groove matching structure with inclined sidewalls is specifically an interlocking structure of an isosceles trapezoidal boss and a corresponding isosceles trapezoidal groove. The angles between the two sidewalls of the isosceles trapezoidal boss and the normal to the lamination plane are equal, both being an inclination angle α.

[0012] As a further improvement to the technical solution of the present invention, the initial design range of the tilt angle α is 2°-10°, the tilt angle α is an acute angle, and the cross-sectional area of ​​the isosceles trapezoidal boss gradually increases along the lamination stacking direction.

[0013] As a further improvement to the technical solution of this invention, based on a preset riveting force threshold, the riveting force simulation and physical testing of the self-riveting buckle points corresponding to different tilt angles α specifically include:

[0014] A finite element simulation model of the self-riveting snap-fit ​​process was established to simulate the plastic deformation process and interlocking stress distribution of the snap-fit ​​point under different tilt angles α, and the simulated riveting force was calculated.

[0015] According to different tilt angles α, corresponding stamped specimens are made, and the axial pull-out test of the stacked stamped specimens is carried out using a universal testing machine to obtain the actual test riveting force.

[0016] The simulated riveting force was compared and verified with the actual tested riveting force, and the material parameters and boundary conditions of the finite element simulation model were corrected.

[0017] As a further improvement to the technical solution of this invention, based on simulation and test results, the optimal range of tilt angle α that satisfies the preset riveting force threshold is specifically determined to include:

[0018] Candidate ranges of tilt angles α where both simulated riveting force and actual test riveting force are greater than or equal to a preset riveting force threshold are selected;

[0019] Within the candidate range, the interval of tilt angle α corresponding to the minimum die wear and the highest utilization rate of the stamping material is selected as the optimal range.

[0020] As a further improvement to the technical solution of the present invention, the parameters of the isosceles trapezoidal boss also include the snap point height h, the root width b1, and the head width b2, wherein the snap point height h is 0.8-0.95 times the stamping thickness t, and the relationship between the head width b2 and the root width b1 is b2=b1+2h×tana.

[0021] As a further improvement to the technical solution of this invention, the optimal range of the tilt angle α is adjusted according to the different thicknesses t of the lamination:

[0022] When the thickness t of the lamination is 0.3mm-0.4mm, the optimal range of the tilt angle α is 3°-5°.

[0023] When the thickness t of the lamination is 0.4mm-0.6mm, the optimal range of the tilt angle α is 4°-7°.

[0024] When the thickness t of the lamination is 0.6mm-0.8mm, the optimal range of the tilt angle α is 6°-8°.

[0025] As a further improvement to the technical solution of this invention, after completing the design of the self-riveting fasteners for the motor laminations, the invention also includes a step of designing the arrangement of the self-riveting fasteners:

[0026] The number of self-riveting points and their circumferential arrangement angle are determined based on the outer diameter of the motor laminations and the thickness of the iron core.

[0027] Multiple self-rivet points are evenly arranged along the circumference of the motor lamination, and the inclination angle α of adjacent self-rivet points is alternately set.

[0028] As a further improvement to the technical solution of this invention, after completing the design of the self-riveting fasteners for the motor laminations, a step of matching the lamination process parameters is also included:

[0029] Based on the determined optimal range of tilt angle α, adjust the pressing force and holding time during lamination stacking;

[0030] The pressing force increases linearly with the increase of the tilt angle α, and the holding time is set to 2s-5s.

[0031] Secondly, the present invention provides a self-riveting fastening point design system for motor laminations, comprising:

[0032] The structure definition module is used to determine the basic geometric structure of the self-riveting fastener of the motor lamination. The basic geometric structure is a boss-groove matching structure with inclined sidewalls.

[0033] An angle design module is used to design the inclination angle α between the sidewall of the self-riveting fastener and the normal to the plane of the punch piece. By adjusting the size of the inclination angle α, the engagement contact area and stress distribution during the riveting of the fastener are changed.

[0034] The simulation test module is used to simulate and test the riveting force of self-rivet points corresponding to different tilt angles α based on a preset riveting force threshold.

[0035] The parameter optimization module is used to determine the optimal range of tilt angle α that meets the preset riveting force threshold based on simulation and test results, and to complete the design of the self-riveting fastener of the motor lamination.

[0036] Compared with the prior art, the present invention has the following advantages:

[0037] This invention breaks through the structural limitations of traditional rectangular and circular snap-fit ​​points by determining the matching basic geometry of the boss-groove with inclined sidewalls. It innovatively designs an inclination angle α between the sidewall of the self-riveting snap-fit ​​point and the normal to the lamination plane, utilizing the wedge-shaped interlocking effect of the inclined sidewall to change the interlocking contact area and stress distribution during snap-fitting. This improves the riveting strength of the snap-fit ​​point from the perspective of mechanical interlocking mechanism. Combined with bidirectional verification through finite element simulation and physical testing based on a preset riveting force threshold, the optimal range of inclination angle α that meets the requirements is accurately determined. This significantly improves the single-point riveting force of the self-riveting snap-fit ​​point without increasing the number of snap-fit ​​points or the overall size, or increasing the stacking and pressing force. Simultaneously, it effectively avoids the drawbacks of traditional solutions, such as reduced silicon steel material utilization, deterioration of core magnetic properties, and accelerated die wear. It achieves synergistic optimization of riveting force, material utilization, magnetic properties, and die life, fundamentally solving the problem of lamination loosening and misalignment caused by insufficient riveting force of the self-riveting snap-fit ​​point in motor laminations. This improves the operational stability and reliability of the motor core and reduces the manufacturing and maintenance costs of the motor. Attached Figure Description

[0038] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0039] Figure 1 This is an exemplary flowchart of a self-riveting snap point design method for motor laminations according to some embodiments of the present invention;

[0040] Figure 2 This is a comparison curve of riveting force tests corresponding to different tilt angles α according to some embodiments of the present invention;

[0041] Figure 3 This is a schematic diagram of the circumferential arrangement of self-riveting points of motor laminations according to some embodiments of the present invention;

[0042] Figure 4This is a structural schematic diagram of a motor lamination self-riveting fastening point design system according to some embodiments of the present invention;

[0043] Figure 5 This is a schematic diagram of the structure of a computer device for implementing a self-riveting fastener design method for motor laminations, as shown in some embodiments of the present invention. Detailed Implementation

[0044] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0045] The present invention will be further described in detail below with reference to the accompanying drawings.

[0046] Reference Figure 1 In a first aspect, the present invention provides a method for designing self-riveting fasteners for motor laminations, comprising the following steps:

[0047] The basic geometric structure of the self-riveting fastening point of the motor lamination is determined, wherein the basic geometric structure is a boss-groove matching structure with inclined sidewalls;

[0048] Design the inclination angle α between the sidewall of the self-riveting fastener and the normal to the plane of the punch, and change the engagement contact area and stress distribution of the fastener during riveting by adjusting the size of the inclination angle α.

[0049] Based on the preset riveting force threshold, the riveting force of the self-riveting points corresponding to different tilt angles α is simulated and tested in practice.

[0050] Based on simulation and test results, the optimal range of tilt angle α that satisfies the preset riveting force threshold was determined, and the design of the self-riveting fastener of the motor lamination was completed.

[0051] In practical implementation, the self-riveting fastener of the motor lamination is first determined to adopt a boss-groove matching basic geometric structure with inclined sidewalls, breaking through the structural limitations of traditional rectangular and circular fasteners. By designing the inclination angle α between the sidewall of the self-riveting fastener and the normal of the lamination plane, the wedge-shaped interlocking effect of the inclined sidewall is used to change the interlocking contact area and stress distribution during the riveting process, thereby improving the riveting strength from the core mechanism of mechanical interlocking. Then, based on the preset riveting force threshold, the fasteners corresponding to different inclination angles α are verified by both finite element simulation and physical testing. Finally, the optimal range of inclination angle α that meets the performance requirements is accurately determined, completing the systematic design of the self-riveting fastener.

[0052] This invention significantly improves the single-point riveting force of self-riveting points without increasing the number of snap-fit ​​points or the overall size, or by increasing the stacking and pressing force. At the same time, it effectively avoids the drawbacks of traditional solutions, such as reduced utilization of silicon steel materials, deterioration of the magnetic properties of the iron core, and accelerated wear of the punching die. It achieves synergistic optimization of riveting force, material utilization, magnetic properties, and punching die life, fundamentally solving the problem of loosening and misalignment of stacked laminations caused by insufficient riveting force of self-riveting points in motor laminations. This improves the operational stability and reliability of the motor iron core and reduces the manufacturing and maintenance costs of the motor.

[0053] In some embodiments, the boss-groove matching structure with inclined sidewalls is specifically an interlocking structure of an isosceles trapezoidal boss and a corresponding isosceles trapezoidal groove, wherein the two sidewalls of the isosceles trapezoidal boss have equal angles with the normal to the lamination plane, both being inclined angle α.

[0054] It should be noted that the boss-groove matching structure with inclined sidewalls is specifically defined as an interlocking structure of an isosceles trapezoidal boss and a corresponding isosceles trapezoidal groove, so that the angles between the two sidewalls of the isosceles trapezoidal boss and the normal to the plane of the punch are equal and both are inclined angle α. By utilizing the geometric symmetry of the isosceles structure, it is ensured that the snap points of the upper and lower punches can be accurately aligned during the stacking process, and the force on the snap point engagement surface is evenly distributed.

[0055] This invention effectively avoids uneven deformation of the fastening points and misalignment of the stamping pieces caused by stress concentration on one side, improves the stability of the riveting process and the consistency of the riveting strength, and at the same time reduces the processing difficulty of the stamping die and the assembly accuracy requirements.

[0056] In some embodiments, the initial design range of the tilt angle α is 2°-10°, the tilt angle α is an acute angle, and the cross-sectional area of ​​the isosceles trapezoidal boss gradually increases along the lamination stacking direction.

[0057] It should be noted that the initial design range of the tilt angle α is limited to an acute angle range of 2° to 10°. This range is determined based on the plastic deformation characteristics of silicon steel material and the processing technology of the stamping die. At the same time, it is limited that the cross-sectional area of ​​the isosceles trapezoidal boss gradually increases along the stamping lamination direction, so that the fastening point forms a hook-type mechanical interlocking structure after the lamination and riveting.

[0058] This invention maximizes the wedge-shaped interlocking effect of the inclined sidewalls while ensuring the feasibility of die processing and the quality of stamping. This avoids the limited increase in riveting force caused by an excessively small inclination angle, as well as the problems of stress concentration, accelerated wear, and stamping cracking caused by an excessively large inclination angle. At the same time, the barbed interlocking structure can effectively resist axial pull-out force, further improving the riveting strength.

[0059] In some embodiments, based on a preset riveting force threshold, the simulation and physical testing of riveting force at self-riveting points corresponding to different tilt angles α specifically includes:

[0060] A finite element simulation model of the self-riveting snap-fit ​​process was established to simulate the plastic deformation process and interlocking stress distribution of the snap-fit ​​point under different tilt angles α, and the simulated riveting force was calculated.

[0061] According to different tilt angles α, corresponding stamped specimens are made, and the axial pull-out test of the stacked stamped specimens is carried out using a universal testing machine to obtain the actual test riveting force.

[0062] The simulated riveting force was compared and verified with the actual tested riveting force, and the material parameters and boundary conditions of the finite element simulation model were corrected.

[0063] It should be noted that by establishing a finite element simulation model of the self-riveting point overlapping riveting process, the plastic deformation process and interlocking stress distribution of the fastening point under different tilt angles α are simulated, and the simulated riveting force is quickly calculated; then, a stamped sample corresponding to the tilt angle α is made, and the axial pull-out test is performed using a universal testing machine to obtain the actual test riveting force; finally, by comparing the simulation and actual test results, the material parameters and boundary conditions of the finite element model are corrected to improve the accuracy of the simulation.

[0064] This invention enables the digital and quantitative verification of self-rivet point design, avoiding the blindness of purely empirical design, significantly shortening the R&D cycle, reducing the cost and workload of physical testing, and ensuring the reliability and repeatability of the design results.

[0065] In some embodiments, determining the optimal range of tilt angle α that satisfies the preset riveting force threshold based on simulation and test results specifically includes:

[0066] Candidate ranges of tilt angles α where both simulated riveting force and actual test riveting force are greater than or equal to a preset riveting force threshold are selected;

[0067] Within the candidate range, the interval of tilt angle α corresponding to the minimum die wear and the highest utilization rate of the stamping material is selected as the optimal range.

[0068] In practice, the candidate range of tilt angle α that meets the preset riveting force threshold is first selected. Then, within the candidate range, the two key indicators of die wear and sheet material utilization are comprehensively evaluated, and the tilt angle α range with the best overall performance is selected as the final optimal value range.

[0069] This invention achieves multi-objective collaborative optimization, avoiding the problems of shortened die life and reduced material utilization caused by solely pursuing riveting force. It enables the design scheme to meet performance requirements while taking into account manufacturability and economy, thereby enhancing the engineering practical value of the scheme.

[0070] In some embodiments, the parameters of the isosceles trapezoidal boss further include the snap point height h, the root width b1, and the head width b2, wherein the snap point height h is 0.8-0.95 times the sheet thickness t, and the head width b2 is related to the root width b1 by the formula b2=b1+2h×tana.

[0071] It should be noted that the buckle height h is limited to 0.8 to 0.95 times the stamping thickness t. This value can ensure that the buckle has sufficient engagement depth and prevent the stamping from being punched through. At the same time, based on the geometric characteristics of the isosceles trapezoid, a quantitative relationship is established between the head width b2 and the root width b1, the buckle height h and the tilt angle a, so as to realize the standardized calculation of the buckle parameters.

[0072] This invention achieves precise matching of the geometric parameters of the fastening points, avoids arbitrariness in parameter design, ensures consistent riveting quality for stamping pieces of different specifications, and simplifies the design process and improves design efficiency.

[0073] In some embodiments, the optimal range of the tilt angle α is adjusted according to the different thicknesses t of the lamination:

[0074] When the thickness t of the lamination is 0.3mm-0.4mm, the optimal range of the tilt angle α is 3°-5°.

[0075] When the thickness t of the lamination is 0.4mm-0.6mm, the optimal range of the tilt angle α is 4°-7°.

[0076] When the thickness t of the lamination is 0.6mm-0.8mm, the optimal range of the tilt angle α is 6°-8°.

[0077] It should be noted that, based on the differences in the plastic deformation capacity of silicon steel sheets of different thicknesses, the optimal range of the tilt angle α is adjusted accordingly. Thin-gauge laminations have stronger plastic deformation capacity, and a smaller tilt angle is sufficient to obtain adequate riveting force; thick-gauge laminations have weaker plastic deformation capacity, requiring a larger tilt angle to ensure the amount of plastic deformation and engagement strength of the fastening point. This invention provides precise tilt angle design guidelines for motor laminations of different thicknesses, improving the versatility and adaptability of the method for laminations of different specifications, and ensuring that the self-riveting fastening points of laminations of various thicknesses can achieve optimal riveting performance.

[0078] In some embodiments, after completing the design of the self-riveting fasteners for the motor laminations, the method further includes a step of designing the arrangement of the self-riveting fasteners:

[0079] The number of self-riveting points and their circumferential arrangement angle are determined based on the outer diameter of the motor laminations and the thickness of the iron core.

[0080] Multiple self-rivet points are evenly arranged along the circumference of the motor lamination, and the inclination angle α of adjacent self-rivet points is alternately set.

[0081] It should be noted that the number of self-riveting points and the circumferential arrangement angle are determined according to the outer diameter of the motor lamination and the thickness of the iron core. Multiple self-riveting points are evenly arranged along the circumferential direction of the lamination to make the riveting force evenly distributed in the entire lamination plane. At the same time, the inclination angle α of adjacent self-riveting points is alternately set to counteract the circumferential torsional stress on the iron core during operation.

[0082] This invention significantly improves the overall mechanical strength and torsional resistance of the motor core, avoids lamination loosening and deformation caused by local stress concentration, and ensures the operational stability of the core under high-speed rotation and frequent start-stop conditions.

[0083] In some embodiments, after completing the design of the self-riveting fasteners for the motor laminations, the method further includes a step of matching the lamination process parameters:

[0084] Based on the determined optimal range of tilt angle α, adjust the pressing force and holding time during lamination stacking;

[0085] The pressing force increases linearly with the increase of the tilt angle α, and the holding time is set to 2s-5s.

[0086] It should be noted that, based on the determined optimal range of tilt angle α, the pressing force and holding time during the lamination stacking are adjusted accordingly, so that the pressing force increases linearly with the increase of tilt angle α, ensuring that the fastening points with different tilt angles can obtain sufficient plastic deformation; at the same time, the holding time is set to 2s to 5s to ensure that the plastic deformation of the fastening points is fully stabilized and to avoid the decrease in riveting force caused by springback.

[0087] This invention achieves synergistic optimization of the self-riveting point structural parameters and the stacking process parameters, ensuring the stability and consistency of riveting strength and avoiding fluctuations in riveting quality caused by mismatched process parameters.

[0088] Reference Figure 2 Secondly, the present invention provides a self-riveting fastening point design system for motor laminations, comprising:

[0089] The structure definition module is used to determine the basic geometric structure of the self-riveting fastener of the motor lamination. The basic geometric structure is a boss-groove matching structure with inclined sidewalls.

[0090] An angle design module is used to design the inclination angle α between the sidewall of the self-riveting fastener and the normal to the plane of the punch piece. By adjusting the size of the inclination angle α, the engagement contact area and stress distribution during the riveting of the fastener are changed.

[0091] The simulation test module is used to simulate and test the riveting force of self-rivet points corresponding to different tilt angles α based on a preset riveting force threshold.

[0092] The parameter optimization module is used to determine the optimal range of tilt angle α that meets the preset riveting force threshold based on simulation and test results, and to complete the design of the self-riveting fastener of the motor lamination.

[0093] It should be noted that the basic geometric structure of the self-riveting point is determined by the structure definition module, the preliminary design of the tilt angle α is completed by the angle design module and its influence on the interlocking contact area and stress distribution is analyzed by the angle design module, the riveting force simulation and physical test verification of different tilt angles α are completed by the simulation test module, and the optimal value range of the tilt angle α is determined by the parameter optimization module. All modules work together to complete the entire process design of the self-riveting point.

[0094] This invention automates and standardizes the design process of self-riveting fasteners for motor laminations, improves design efficiency, reduces design errors caused by human factors, and facilitates the storage and reuse of design results, thereby enhancing the R&D and production efficiency of enterprises.

[0095] To provide a clearer understanding of the invention, the invention is further described below:

[0096] refer to Figure 1 The figure is an exemplary flowchart of a self-riveting fastener design method for motor laminations according to some embodiments of the present invention. This self-riveting fastener design method for motor laminations mainly includes the following steps:

[0097] In step 101, the basic geometric structure of the self-riveting fastening point of the motor lamination is determined. The basic geometric structure is a boss-groove matching structure with inclined sidewalls.

[0098] In practical implementation, firstly, based on the performance requirements of the motor core and the material characteristics of the laminations, the basic geometric structure of the self-riveting fastener is determined to be a boss-groove matching structure with inclined sidewalls. This structure differs from traditional rectangular and circular fasteners. Its core feature is that the sidewalls of the fastener have a certain inclination angle, which can form a wedge-shaped interlocking effect during the stacking and riveting process. In this embodiment, the boss-groove matching structure with inclined sidewalls is specifically an interlocking structure of an isosceles trapezoidal boss and a corresponding isosceles trapezoidal groove. The two sidewalls of the isosceles trapezoidal boss have equal angles with the normal to the lamination plane, both being inclination angle α. Along the lamination stacking direction, the cross-sectional area of ​​the isosceles trapezoidal boss gradually increases, while the cross-sectional area of ​​the corresponding isosceles trapezoidal groove gradually decreases, thereby forming a tight wedge-shaped engagement during stacking.

[0099] In step 102, the inclination angle α between the side wall of the self-riveting fastener and the normal of the punch plane is designed. The engagement contact area and stress distribution during the riveting of the fastener are changed by adjusting the size of the inclination angle α.

[0100] In practice, the initial design range of the tilt angle α is set to 2°-10°. This range is determined based on the plastic deformation characteristics of silicon steel and the processing technology of the die. When the tilt angle α is less than 2°, the wedge interlocking effect is not obvious, and the increase in riveting force is limited. When the tilt angle α is greater than 10°, the tilt of the snap-in sidewall is too large, which will lead to increased stress concentration in the punch and die of the die, faster die wear, and cracking of the stamped pieces during the stacking process.

[0101] By adjusting the tilt angle α, the contact area and stress distribution during snap-fit ​​can be significantly altered: as the tilt angle α increases, the contact area of ​​the snap-fit ​​surface gradually increases, while the normal stress component and tangential stress component of the contact surface gradually decrease, thereby significantly improving the mechanical interlocking strength of the snap-fit. (Reference) Figure 2 As shown in the figure, this figure is a comparison curve of the riveting force test corresponding to different tilt angles α of the present invention. It can be seen from the figure that in the range of 2°-10°, the riveting force of the self-rivet point shows a trend of first rising rapidly and then leveling off as the tilt angle α increases.

[0102] In step 103, based on the preset riveting force threshold, the riveting force of the self-riveting points corresponding to different tilt angles α is simulated and tested physically.

[0103] In some embodiments, based on a preset riveting force threshold, the simulation and physical testing of riveting force at self-riveting points corresponding to different tilt angles α specifically includes:

[0104] A finite element simulation model of the self-riveting snap fastener overlapping riveting process was established to simulate the plastic deformation process and interlocking stress distribution of the snap fastener under different tilt angles α, and to calculate the simulated riveting force. Specifically, a three-dimensional simulation model was established using ABAQUS finite element analysis software. The material model was an elastoplastic constitutive model of silicon steel sheet. The friction coefficient between the lamination and the die was set to 0.15, and the overlapping pressing force was set to 10 kN. Explicit dynamic analysis was used to simulate the entire process of snap fastener stamping and overlapping riveting, extracting the contact stress and contact area of ​​the snap fastener interlocking surface, and calculating the simulated riveting force.

[0105] According to different tilt angles α, corresponding lamination samples were fabricated. A universal testing machine was used to perform axial pull-out tests on the stacked lamination samples to obtain the actual test riveting force. Specifically, a CNC punch press was used to process 50W470 silicon steel lamination samples with different tilt angles α. Ten sets of samples were fabricated for each tilt angle α, with each set consisting of 10 laminations stacked together. The stacking pressure was consistent with the simulation conditions. A CMT5105 universal testing machine was used for axial pull-out tests, with the tensile speed set to 2 mm / min. The maximum load during sample pull-out was recorded, and the average value of the 10 sets of samples was taken as the actual test riveting force corresponding to that tilt angle α.

[0106] The simulated riveting force is compared and verified with the actual tested riveting force to correct the material parameters and boundary conditions of the finite element simulation model. In practice, the relative error between the simulated riveting force and the actual tested riveting force is calculated. When the relative error is greater than 10%, parameters such as the material yield strength and friction coefficient in the simulation model are adjusted until the relative error is less than 10%, ensuring the accuracy of the simulation model.

[0107] In step 104, based on the simulation and test results, the optimal range of tilt angle α that satisfies the preset riveting force threshold is determined, and the design of the self-riveting fastener of the motor lamination is completed.

[0108] In some embodiments, determining the optimal range of tilt angle α that satisfies the preset riveting force threshold based on simulation and test results specifically includes:

[0109] Candidate ranges of tilt angles α where both simulated and actual tested riveting forces are greater than or equal to a preset riveting force threshold are selected. In this embodiment, the preset single-point riveting force threshold is 150N. Figure 3 According to the test results, when the tilt angle α is greater than or equal to 3°, the riveting force can reach more than 150N, so the candidate range is 3°-10°.

[0110] Within the candidate range, the optimal value range for the tilt angle α is selected as the interval corresponding to the minimum die wear and the highest material utilization rate of the stamping. In practice, die wear simulation and actual stamping tests are conducted to test the die wear and material utilization rate of the stamping under different tilt angles α. The results show that when the tilt angle α is in the range of 3°-8°, the die wear is small and the material utilization rate is high. Therefore, the optimal value range for the tilt angle α is determined to be 3°-8°.

[0111] In some embodiments, the parameters of the isosceles trapezoidal boss further include the snap-in height h, the root width b1, and the head width b2. The snap-in height h is 0.8-0.95 times the lamination thickness t. This range ensures sufficient engagement depth while preventing the lamination from being punched through. The head width b2 is related to the root width b1 by the formula b2 = b1 + 2h × tanα. This formula allows for the rapid calculation of the head width b2 based on the tilt angle α and the root width b1, achieving standardized design of the snap-in parameters.

[0112] In some embodiments, the optimal range of the tilt angle α is adjusted according to the different thicknesses t of the lamination:

[0113] When the thickness t of the lamination is 0.3mm-0.4mm, the lamination has strong plastic deformation ability, and the optimal range of the tilt angle α is 3°-5°.

[0114] When the thickness t of the lamination is 0.4mm-0.6mm, the plastic deformation capacity of the lamination is moderate, and the optimal range of the tilt angle α is 4°-7°.

[0115] When the thickness t of the stamping is 0.6mm-0.8mm, the plastic deformation capacity of the stamping is relatively weak, and a larger tilt angle is required to ensure the riveting force. Therefore, the optimal value range of the tilt angle α is 6°-8°.

[0116] In some embodiments, after completing the design of the self-riveting fasteners for the motor laminations, the design also includes a step of arranging the self-riveting fasteners, as described in the following reference. Figure 3 As shown in the figure, this is a schematic diagram of the circumferential arrangement of the self-riveting fastening points of the motor laminations of the present invention:

[0117] The number of self-riveting fasteners and their circumferential arrangement angle are determined based on the outer diameter of the motor lamination and the thickness of the iron core. For example, for a motor lamination with an outer diameter of 200mm and a thickness of 100mm, 6 self-riveting fasteners are set, and the circumferential arrangement angle between adjacent fasteners is 60°.

[0118] Multiple self-riveting points are evenly arranged along the circumference of the motor lamination, with the inclination angle α of adjacent self-riveting points alternating. This arrangement allows for a more uniform distribution of riveting force in the core, avoiding localized stress concentration and improving the core's torsional resistance.

[0119] In some embodiments, after completing the design of the self-riveting fasteners for the motor laminations, the method further includes a step of matching the lamination process parameters:

[0120] Based on the determined optimal range of the tilt angle α, the pressing force and holding time during lamination stacking are adjusted. The pressing force increases linearly with the tilt angle α, specifically F = F0 + k × a, where F0 is the basic pressing force when the tilt angle α = 0°, and k is the pressing force adjustment coefficient, with a value of 0.5 kN / °. The holding time is set to 2-5 seconds to ensure that the snap-fit ​​points can fully complete plastic deformation and form a stable interlocking structure.

[0121] Furthermore, in another aspect of the present invention, in some embodiments, the present invention provides a self-riveting snap-on design system for motor laminations, as referenced. Figure 4 The figure is a schematic diagram of a self-riveting fastener design system for motor laminations according to some embodiments of the present invention. This system includes: a structure definition module, an angle design module, a simulation testing module, and a parameter optimization module, which are described below:

[0122] The structure definition module in this invention is mainly used to determine the basic geometric structure of the self-riveting fastener of the motor lamination. The basic geometric structure is a boss-groove matching structure with inclined sidewalls.

[0123] Angle design module: In this invention, the angle design module is mainly used to design the inclination angle α between the side wall of the self-riveting fastener and the normal line of the punch plane. By adjusting the size of the inclination angle α, the interlocking contact area and stress distribution during the riveting of the fastener are changed.

[0124] The simulation testing module in this invention is mainly used to simulate and test the riveting force of self-rivet points corresponding to different tilt angles α based on a preset riveting force threshold.

[0125] The parameter optimization module in this invention is mainly used to determine the optimal range of tilt angle α that meets the preset riveting force threshold based on simulation and test results, and to complete the design of the self-riveting fastener of the motor lamination.

[0126] Each module in the aforementioned motor lamination self-riveting fastener design system can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in the processor of a computer device in hardware form or independent of it, or stored in the memory of a computer device in software form, so that the processor can call and execute the corresponding operations of each module.

[0127] In another embodiment, the present invention provides a computer device, which may be a server, and its internal structure diagram may be as follows: Figure 5 As shown, the computer device includes a processor, memory, and a network interface connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system, computer programs, and a database. The internal memory provides an environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The network interface is used for communication with external terminals via a network connection. When the computer program is executed by the processor, it implements a method for designing self-riveting fasteners for motor laminations.

[0128] Those skilled in the art will understand that Figure 5 The structure shown is merely a block diagram of a portion of the structure related to the present invention and does not constitute a limitation on the computer device to which the present invention is applied. A specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0129] In one embodiment, a computer device is also provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps in the above embodiment of the self-riveting fastening point design method for motor laminations.

[0130] In one embodiment, a computer-readable storage medium is provided storing a computer program that, when executed by a processor, implements the steps in the above embodiment of the motor lamination self-riveting fastener design method.

[0131] In one embodiment, a computer program product or computer program is provided, comprising computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the computer device to perform the steps described in the embodiment of the self-riveting fastener design method for motor laminations.

[0132] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the methods described above. Any references to memory, storage, databases, or other media used in the embodiments provided by this invention can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, or optical storage, etc. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0133] The technical solutions provided by the embodiments disclosed in this invention have the following beneficial effects:

[0134] The self-riveting snap-fit ​​point design method and system for motor laminations provided by this invention firstly determines the basic geometric structure of the boss-groove matching with inclined sidewalls, breaking through the structural limitations of traditional rectangular and circular snap-fit ​​points and laying the structural foundation for improving riveting force through angle optimization. Secondly, the inclination angle α between the sidewall of the self-riveting snap-fit ​​point and the normal line of the lamination plane is designed. By adjusting the size of the inclination angle α, the interlocking contact area and stress distribution during snap-fit ​​are changed. This step utilizes the wedge-shaped interlocking effect of the inclined sidewall to generate more uniform plastic deformation of the snap-fit ​​point during the stacking process, while increasing the normal stress of the interlocking surface, fundamentally improving the mechanical interlocking strength of the snap-fit ​​point. Then, based on a preset riveting force threshold, the riveting force of the self-riveting snap-fit ​​points corresponding to different inclination angles α is simulated and tested physically. Through two-way verification of simulation and physical objects, the accuracy and reliability of the angle parameter design are ensured. Finally, the optimal range of inclination angle α that meets the preset riveting force threshold is determined, realizing the precise design of the snap-fit ​​point parameters.

[0135] By adopting the solution of this invention, without increasing the number of snap points or the overall size of the snap points, the single-point riveting force of the self-riveting snap points can be increased by 30%-60%, while the material utilization rate of the stamping sheet is increased by 5%-8%, and the service life of the stamping die is extended by 15%-25%. This effectively solves the contradiction between riveting force, material utilization rate and stamping die life in traditional snap point design, significantly improves the operational stability and reliability of the motor core, and reduces the manufacturing and maintenance costs of the motor.

[0136] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for designing self-riveting fasteners for motor laminations, characterized in that, Includes the following steps: The basic geometric structure of the self-riveting fastening point of the motor lamination is determined, wherein the basic geometric structure is a boss-groove matching structure with inclined sidewalls; Design the inclination angle α between the sidewall of the self-riveting fastener and the normal to the plane of the punch, and change the engagement contact area and stress distribution of the fastener during riveting by adjusting the size of the inclination angle α. Based on the preset riveting force threshold, the riveting force of the self-riveting points corresponding to different tilt angles α is simulated and tested in practice. Based on simulation and test results, the optimal range of tilt angle α that satisfies the preset riveting force threshold was determined, and the design of the self-riveting fastener of the motor lamination was completed.

2. The self-riveting fastening point design method for motor laminations as described in claim 1, characterized in that, The boss-groove matching structure with inclined sidewalls is specifically an interlocking structure of an isosceles trapezoidal boss and a corresponding isosceles trapezoidal groove. The two sidewalls of the isosceles trapezoidal boss have equal angles with the normal to the lamination plane, both being inclined angle α.

3. The self-riveting fastening point design method for motor laminations as described in claim 2, characterized in that, The initial design range of the tilt angle α is 2°-10°. The tilt angle α is an acute angle, and the cross-sectional area of ​​the isosceles trapezoidal boss gradually increases along the lamination direction.

4. The self-riveting fastening point design method for motor laminations as described in claim 1, characterized in that, Based on a preset riveting force threshold, the riveting force simulation and physical testing of the self-riveting points corresponding to different tilt angles α specifically include: A finite element simulation model of the self-riveting snap-fit ​​process was established to simulate the plastic deformation process and interlocking stress distribution of the snap-fit ​​point under different tilt angles α, and the simulated riveting force was calculated. According to different tilt angles α, corresponding stamped specimens are made, and the axial pull-out test of the stacked stamped specimens is carried out using a universal testing machine to obtain the actual test riveting force. The simulated riveting force was compared and verified with the actual tested riveting force, and the material parameters and boundary conditions of the finite element simulation model were corrected.

5. The self-riveting fastening point design method for motor laminations as described in claim 4, characterized in that, Based on simulation and testing results, the optimal range of tilt angle α that satisfies the preset riveting force threshold is determined to include: Candidate ranges of tilt angles α where both simulated riveting force and actual test riveting force are greater than or equal to a preset riveting force threshold are selected; Within the candidate range, the interval of tilt angle α corresponding to the minimum die wear and the highest utilization rate of the stamping material is selected as the optimal range.

6. The self-riveting fastening point design method for motor laminations as described in claim 2, characterized in that, The parameters of the isosceles trapezoidal boss also include the snap point height h, the root width b1, and the head width b2. The snap point height h is 0.8-0.95 times the sheet thickness t. The head width b2 is related to the root width b1 by the formula b2=b1+2h×tana.

7. The self-riveting fastening point design method for motor laminations as described in claim 6, characterized in that, The optimal range of the tilt angle α is adjusted accordingly based on the different thicknesses t of the lamination. When the thickness t of the lamination is 0.3mm-0.4mm, the optimal range of the tilt angle α is 3°-5°. When the thickness t of the lamination is 0.4mm-0.6mm, the optimal range of the tilt angle α is 4°-7°. When the thickness t of the lamination is 0.6mm-0.8mm, the optimal range of the tilt angle α is 6°-8°.

8. The self-riveting fastening point design method for motor laminations as described in claim 1, characterized in that, After completing the design of the self-riveting fasteners for the motor laminations, the design process also includes the layout design of the self-riveting fasteners: The number of self-riveting points and their circumferential arrangement angle are determined based on the outer diameter of the motor laminations and the thickness of the iron core. Multiple self-rivet points are evenly arranged along the circumference of the motor lamination, and the inclination angle α of adjacent self-rivet points is alternately set.

9. The self-riveting fastening point design method for motor laminations as described in claim 1, characterized in that, After completing the design of the self-riveting fasteners for the motor laminations, the process also includes matching the lamination process parameters. Based on the determined optimal range of tilt angle α, adjust the pressing force and holding time during lamination stacking; The pressing force increases linearly with the increase of the tilt angle α, and the holding time is set to 2s-5s.

10. A self-riveting fastening point design system for motor laminations, characterized in that, include: The structure definition module is used to determine the basic geometric structure of the self-riveting fastener of the motor lamination. The basic geometric structure is a boss-groove matching structure with inclined sidewalls. An angle design module is used to design the inclination angle α between the sidewall of the self-riveting fastener and the normal to the plane of the punch piece. By adjusting the size of the inclination angle α, the engagement contact area and stress distribution during the riveting of the fastener are changed. The simulation test module is used to simulate and test the riveting force of self-riveting points corresponding to different tilt angles α based on a preset riveting force threshold. The parameter optimization module is used to determine the optimal range of tilt angle α that meets the preset riveting force threshold based on simulation and test results, and to complete the design of the self-riveting fastener of the motor lamination.

Images