Drop resistance optimization design method of integrally formed inductor based on dangerous area identification

Abstract

This invention discloses a drop-resistance optimization design method for integral molded inductors based on hazardous area identification, comprising: 1. establishing a three-dimensional structural model including a magnetic core, coil, pins, welded connections, and substrate; 2. establishing an explicit dynamic drop finite element model; applying preset drop conditions and acquiring mechanical response data; 3. determining hazardous areas based on peak distribution, stress concentration locations, or deformation concentration locations; 4. using the material and structural parameters corresponding to the hazardous areas as optimization variables for parameterized adjustment, iteratively obtaining the optimized parameter combination. This invention aims to improve the drop-resistance reliability of integral molded inductors in transportation, assembly, and portable electronic product drop scenarios, reduce the cost of repeated prototyping and whole-device drop verification, and provide quantifiable simulation basis for device structure design, material selection, and process optimization.

Description

Technical Field

[0001] This invention belongs to the field of electronic component reliability design and finite element simulation optimization technology, specifically involving a drop-resistant optimization design method for integral molded inductors based on hazardous area identification, which is particularly applicable to drop-resistant optimization of integral molded inductors in portable electronic products, power management modules and board-level interconnect structures. Background Technology

[0002] Molded inductors typically consist of a soft magnetic composite core, winding coils, external leads, and soldered connections. They are characterized by their small size, good shielding performance, high current carrying capacity, and suitability for surface mounting, and are widely used in mobile phones, Bluetooth headsets, tablets, power banks, portable medical electronic devices, and other miniaturized power management circuits. As electronic products become increasingly thinner, lighter, more integrated, and more reliable, the transient mechanical loads that molded inductors endure during transportation, assembly, and use (including drops and impacts) are constantly increasing. Problems such as core cracking, lead deformation, soldered connection detachment, or board-level interconnect failure are gradually becoming key factors affecting product reliability.

[0003] Current drop-resistance design for molded inductors typically relies on empirical structural design, prototype manufacturing, and drop testing. While these methods can indicate whether a sample fails under specific operating conditions, they often only allow for post-failure deduction through visual inspection, metallographic observation, or cross-sectional analysis. They struggle to accurately identify stress concentrations in areas such as the core base transition zone, coil lead bending zone, lead anchoring zone, solder joint zone, and pad edge zone during the design phase. For molded inductors with small dimensions and complex internal interfaces, relying solely on test results to determine the failure source suffers from inaccurate location, long testing cycles, high sample consumption, and low parameter adjustment efficiency.

[0004] Furthermore, the drop resistance of molded inductors is not only affected by their geometry, but also by factors such as the parameters of the soft magnetic composite core material, the strength of the lead material, the interface bonding state, the dimensions of the welded joints, and the substrate support conditions. Existing methods often treat material optimization, structural optimization, and drop testing separately, lacking a parametric design process that links the results of hazardous area identification with material and structural parameters. This leads to unclear optimization directions and easily results in insufficient local reinforcement or structural modifications affecting manufacturing adaptability. Summary of the Invention

[0005] This invention addresses the problems in existing molded inductor drop-resistant designs, such as inaccurate identification of hazardous areas, long product verification cycles, lack of quantitative basis for optimizing material and structural parameters, and difficulty in directly guiding structural design with optimization results. It proposes a drop-resistant optimization design method for molded inductors based on hazardous area identification, aiming to improve the structural reliability and design efficiency of molded inductors under drop impact conditions, thereby reducing the risk of drop failure during transportation, assembly, and end-use.

[0006] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: The present invention provides a method for optimizing the drop resistance design of a molded inductor based on hazardous area identification, which includes the following steps: S1. Establish a three-dimensional structural model of the integral molded inductor drop test. The three-dimensional structural model includes: magnetic core, coil, welding connection part, PCB substrate and drop jig. S2. Based on the three-dimensional structural model, an explicit dynamic drop finite element model is established, and material parameters, contact relationships, constraint conditions and impact boundary conditions are assigned to each component. S3, apply a preset drop condition to the drop finite element model to obtain the mechanical response data of the integral inductor under drop impact; S4. Based on the peak distribution, stress concentration location, or deformation concentration location of the mechanical response data, determine the dangerous area in the integrally molded inductor. S5, set the material parameters and structural parameters corresponding to the dangerous area as optimization variables, and after parameterizing the material parameters and structural parameters, return to S3 to perform drop simulation, thereby obtaining the mechanical response data of the dangerous area under different parameters, including: the maximum principal stress, Von Mises equivalent stress, interface shear stress, plastic strain, contact reaction force or displacement response corresponding to the dangerous area. S6. Based on the mechanical response data of the hazardous area under different parameters, the optimized parameter combination is determined and used as the drop resistance optimization design result of the integral molded inductor.

[0007] The method described in this invention is also characterized in that the material parameters include at least one of the following: density, elastic modulus, Poisson's ratio, yield strength, tensile strength, fracture strength, plasticity parameter, or interfacial bonding strength.

[0008] Furthermore, the preset drop conditions include at least one of the following: drop height, drop direction, impact ground stiffness, contact friction coefficient, or number of repeated drops.

[0009] Furthermore, the dangerous area includes at least one of the following: core base transition area, core-pin junction area, coil pin bending area, pin anchoring area, solder connection area, or pad edge area.

[0010] Furthermore, the structural parameters include at least one of the following: pin bending radius, pin embedment length, pin cross-sectional dimensions, core base fillet radius, core transition section length, weld connection thickness, or pad size.

[0011] Furthermore, the parameterization adjustment is carried out using at least one of the following methods: single-factor adjustment, orthogonal experimental design, response surface optimization, or iterative optimization.

[0012] Furthermore, the optimized parameter combination includes: optimized material parameters, adjusted pin bending radius, adjusted pin embedment length, rounded or beveled transition structure in the core base transition area, and anchoring structure to enhance interface bonding in the pin anchoring area.

[0013] Furthermore, the anchoring structure includes at least one of the following: groove, ridge, stepped surface, roughened surface, indentation structure, or local diameter expansion structure.

[0014] The present invention provides an electronic device, including a memory and a processor, characterized in that the memory is used to store a program supporting the processor in performing the method described therein, and the processor is configured to execute the program stored in the memory.

[0015] The present invention discloses a computer-readable storage medium storing a computer program, characterized in that the computer program is executed by a processor to perform the steps of the method described thereon.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention establishes a three-dimensional structural model of an integrated inductor drop model that includes a magnetic core, coil, welded connection, PCB substrate and drop fixture. In the explicit dynamic drop finite element model, material parameters, contact relationships, constraint conditions and impact boundary conditions are introduced, so that the drop impact response can be quantitatively analyzed in the structural design stage. This overcomes the problem of delayed failure source judgment caused by relying solely on sample prototyping and failure observation after drop.

[0017] 2. This invention identifies dangerous areas by using mechanical response data such as maximum principal stress, Von Mises equivalent stress, interface shear stress, plastic strain, contact reaction force, or displacement response. It can correlate weak parts such as the core base transition area, coil pin bending area, pin anchoring area, welding connection area, and pad edge area with specific mechanical indicators, thereby improving the pertinence of drop-resistant optimization design.

[0018] 3. This invention sets the material and structural parameters corresponding to the hazardous area as optimization variables, and uses methods such as single-factor adjustment, orthogonal experimental design, response surface optimization or iterative optimization for parametric analysis. This enables material selection, interface enhancement and structural modification to be optimized in a coordinated manner around the hazardous area, reducing trial and error without a target and improving optimization efficiency.

[0019] 4. This invention can determine the optimized parameter combination based on the mechanical response data of the dangerous area under different parameter combinations, thereby providing quantifiable basis for the design of pin bending radius, pin embedment length, core base fillet radius, weld connection thickness, pad size and anchoring structure form, which helps to reduce the stress peak in the dangerous area and improve the safety margin.

[0020] 5. The present invention improves the transmission path of impact load between the magnetic core, pin and welded joint by setting a rounded corner or bevel transition structure in the transition area of ​​the magnetic core base, and setting a groove, ridge, stepped surface, roughened surface, indentation structure or local diameter expansion structure in the pin anchoring area to enhance the interface bonding. This reduces the risk of local stress concentration and interface debonding.

[0021] 6. The optimization results of this invention can be used as the drop resistance optimization design results of integral molded inductors to guide sample design, mold structure modification, material system screening and reliability verification scheme formulation, which helps to shorten the product development cycle and improve the board-level reliability of power inductors in portable electronic products. Attached Figure Description

[0022] Figure 1 This is a flowchart of an optimized method for drop resistance of a molded inductor based on hazardous area identification, according to the present invention. Figure 2 This is a three-dimensional structural model diagram of the integral molded inductor drop in an embodiment of the present invention; Figure 3 This is a schematic diagram of the identification results of the dangerous area of ​​the magnetic core in an embodiment of the present invention; Figure 4 This is a schematic diagram of the identification results of the dangerous area of ​​the coil pin in an embodiment of the present invention; Figure 5 This is a schematic diagram comparing the mechanical response of the magnetic core in the dangerous area before and after optimization in an embodiment of the present invention. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood that the following embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. Equivalent substitutions or conventional modifications made by those skilled in the art to relevant parameters, structural forms, solving software, or test conditions without departing from the technical concept of the present invention should all fall within the scope of protection of the present invention.

[0024] like Figure 1 As shown in this embodiment, a drop-resistant optimization design method for integrally molded inductors based on hazardous area identification is a method that can quantitatively analyze the drop impact response of integrally molded inductors, identify hazardous areas, and optimize material and structural parameters for hazardous areas during the design phase. This improves the pertinence and verifiability of drop-resistant structural design. Specifically, the method includes the following steps.

[0025] S1, Establish a three-dimensional structural model of the integral molded inductor drop, such as Figure 2 As shown, the three-dimensional structural model includes: magnetic core, coil, welded connection, PCB substrate and drop jig; the micro-chamfers, local assembly gaps and solder micro-defects are simplified to ensure that the model can reflect the main load transmission path and local stress concentration areas.

[0026] S2. Based on the three-dimensional structural model, an explicit dynamic drop finite element model is established, and material parameters, contact relationships, constraint conditions and impact boundary conditions are assigned to each component. The material parameters include at least one of the following: density, elastic modulus, Poisson's ratio, yield strength, tensile strength, fracture strength, plasticity parameter or interfacial bonding strength.

[0027] In this embodiment, an explicit dynamic drop finite element model is established using Abaqus / Explicit, and corresponding density, elastic modulus, Poisson's ratio, yield strength, tensile strength, or plasticity parameters are assigned according to the material properties of different components.

[0028] S3, apply a preset drop condition to the drop finite element model to obtain the mechanical response data of the integral inductor under drop impact; In the drop test scenario, the drop height is set to 1800 mm. To improve computational efficiency, based on the principle of energy equivalence, the free fall process is converted into an initial velocity input, i.e., an initial velocity of approximately 5942 mm / s is assigned when the model approaches the impact surface. The impact surface can be set as a rigid ground or an equivalent high-stiffness ground, with the static friction coefficient between the ground and the component set to 0.2 and the dynamic friction coefficient set to 0.1.

[0029] S4. Based on the peak distribution, stress concentration location, or deformation concentration location of the mechanical response data, determine the dangerous area in the integral molded inductor; the dangerous area includes at least one of the following: core base transition area, core-pin junction area, coil pin bending area, pin anchoring area, solder connection area, or pad edge area.

[0030] The magnetic core can be treated as a quasi-brittle soft magnetic composite material, with the maximum principal stress as the main failure evaluation index; the coil and pins can be treated as ductile metal materials, with Von Mises equivalent stress as the evaluation index. Figure 3 and Figure 4 The results shown are from the drop simulation. Figure 3 The three-dimensional overall distribution view of part (a) and Figure 3 The bottom longitudinal section sectional view of part (b) shows that the maximum principal stress of the magnetic core is 23.82 MPa, mainly concentrated in the inner rounded corner area where the central column meets the base and the outer edge of the base. Therefore, this area can be identified as the critical area of ​​the magnetic core and used as the target for subsequent optimization of material or structural parameters. Figure 4 It can be seen that the high stress of the coil is mainly concentrated at the root of the pin bend and in the transition area between the pin and the pad, with a peak value of about 78.25 MPa.

[0031] In step S5, the material and structural parameters corresponding to the hazardous area are set as optimization variables. After parametric adjustment of these parameters, the simulation is returned to step S3 to obtain the mechanical response data of the hazardous area under different parameters. The mechanical response data includes the maximum principal stress, Von Mises equivalent stress, interface shear stress, plastic strain, contact reaction force, or displacement response corresponding to the hazardous area. The parametric adjustment is performed using at least one of the following methods: single-factor adjustment, orthogonal experimental design, response surface optimization, or iterative optimization.

[0032] Specifically, based on the hazardous areas identified in S4, the junction of the core center post and the base, the outer edge of the core base, the root of the coil pin bend, and the transition area between the pin and the pad are the key optimization targets. For the hazardous areas of the core, at least one of the following can be set as optimization variables: the elastic modulus, tensile strength, fracture strength, interfacial bonding strength of the core material, the radius of the core base fillet, the length of the core transition section, or the local thickness of the base. For the hazardous areas of the coil and pins, at least one of the following can be set as optimization variables: the pin bend radius, the pin embedment length, the pin cross-sectional dimensions, the thickness of the welded connection, or the pin anchoring structure.

[0033] In this embodiment, the core material parameters are optimized using a single-factor adjustment method, while keeping the drop height, initial velocity, impact surface stiffness, contact relationship, and friction coefficient in S3 unchanged, and the drop simulation analysis is performed again. Figure 5 This shows a comparison of the maximum principal stress distribution before and after optimization of the magnetic core material parameters. Figure 5 Part (a) and Figure 5 As shown in part (b), the peak value of the maximum principal stress in the magnetic core decreased from approximately 23.82 MPa to approximately 17.16 MPa; Figure 5 Part (c) and Figure 5 As shown in section (d), the high-stress area in the bottom partial view has been reduced, indicating that the optimized material parameters can reduce the stress concentration in the dangerous area of ​​the magnetic core and improve the drop resistance safety margin of the magnetic core area. It should be noted that the above stress values ​​are simulation results obtained in this embodiment under specific model size, material parameters and drop conditions, and are only used to illustrate the implementation process of the method of the present invention, and are not intended to limit the scope of protection of the present invention.

[0034] S6. Based on the mechanical response data of the hazardous area under different parameters, the optimized parameter combination is determined and used as the drop resistance optimization design result of the integral molded inductor.

[0035] Specifically, the maximum principal stress, Von Mises equivalent stress, interfacial shear stress, plastic strain, contact reaction force, or displacement response obtained under different combinations of material or structural parameters are compared and analyzed. The main evaluation indicators are the reduction of peak stress in the critical area, the reduction of strength utilization rate, the reduction of plastic strain, the reduction of interfacial shear stress, and the improvement of safety margin. For quasi-brittle soft magnetic composite material regions such as magnetic cores, the ratio of maximum principal stress to tensile strength or fracture strength of the material is compared first. For ductile metal regions such as coils and leads, the ratio of Von Mises equivalent stress to yield strength and the plastic strain level at the root of lead bending are compared first.

[0036] When a certain parameter combination can reduce the maximum principal stress in the critical area of ​​the magnetic core and the equivalent stress in the coil lead bending area without changing the overall shape, mounting compatibility, and basic electrical performance requirements of the device, and without generating new significant stress concentrations in other areas, this parameter combination is determined as the optimized drop-resistant design scheme. This optimized parameter combination includes optimized magnetic core material parameters, adjusted magnetic core base fillet radius, adjusted magnetic core transition section length, adjusted lead bending radius, adjusted lead embedment length, optimized weld connection thickness, and at least one of the following: groove, ridge, stepped surface, roughened surface, indentation structure, or local diameter expansion structure provided in the lead anchoring area.

[0037] Through the above-mentioned optimized design, the local stress concentration of the molded inductor under drop impact can be reduced, the safety margin of the core, coil pins and welded connections can be increased, thereby improving the drop resistance reliability of the molded inductor.

[0038] In this embodiment, an electronic device includes a memory and a processor. The memory stores a program that supports the processor in executing the above-described method, and the processor is configured to execute the program stored in the memory.

[0039] In this embodiment, a computer-readable storage medium stores a computer program, which is executed by a processor to perform the steps of the above method.

Claims

1. A method for optimizing the drop resistance design of a molded inductor based on hazardous area identification, characterized in that, Includes the following steps: S1. Establish a three-dimensional structural model of the integral molded inductor drop test. The three-dimensional structural model includes: magnetic core, coil, welding connection part, PCB substrate and drop jig. S2. Based on the three-dimensional structural model, an explicit dynamic drop finite element model is established, and material parameters, contact relationships, constraint conditions and impact boundary conditions are assigned to each component. S3, apply a preset drop condition to the drop finite element model to obtain the mechanical response data of the integral inductor under drop impact; S4. Based on the peak distribution, stress concentration location, or deformation concentration location of the mechanical response data, determine the dangerous area in the integrally molded inductor. S5, set the material parameters and structural parameters corresponding to the dangerous area as optimization variables, and after parameterizing the material parameters and structural parameters, return to S3 to perform drop simulation, thereby obtaining the mechanical response data of the dangerous area under different parameters, including: the maximum principal stress, Von Mises equivalent stress, interface shear stress, plastic strain, contact reaction force or displacement response corresponding to the dangerous area. S6. Based on the mechanical response data of the hazardous area under different parameters, the optimized parameter combination is determined and used as the drop resistance optimization design result of the integral molded inductor.

2. The method according to claim 1, characterized in that, The material parameters include at least one of the following: density, elastic modulus, Poisson's ratio, yield strength, tensile strength, fracture strength, plasticity parameter, or interfacial bonding strength.

3. The method according to claim 1, characterized in that, The preset drop conditions include at least one of the following: drop height, drop direction, impact ground stiffness, contact friction coefficient, or number of repeated drops.

4. The method according to claim 1, characterized in that, The hazardous areas include at least one of the following: core base transition area, core-pin junction area, coil pin bending area, pin anchoring area, solder connection area, or pad edge area.

5. The method according to claim 1, characterized in that, The structural parameters include at least one of the following: pin bending radius, pin embedment length, pin cross-sectional dimensions, core base fillet radius, core transition section length, welding connection thickness, or pad size.

6. The method according to claim 1, characterized in that, The parameterization adjustment is carried out using at least one of the following methods: single-factor adjustment, orthogonal experimental design, response surface optimization, or iterative optimization.

7. The method according to claim 1, characterized in that, The optimized parameter combination includes: optimized material parameters, adjusted pin bending radius, adjusted pin embedment length, rounded or beveled transition structure in the core base transition area, and anchoring structure to enhance interface bonding in the pin anchoring area.

8. The method according to claim 7, characterized in that, The anchoring structure includes at least one of the following: groove, ridge, stepped surface, roughened surface, indentation structure or local diameter expansion structure.

9. An electronic device, comprising a memory and a processor, characterized in that, The memory is used to store a program that supports a processor in executing the method of any one of claims 1-8, the processor being configured to execute the program stored in the memory.

10. A computer-readable storage medium storing a computer program thereon, characterized in that, The computer program is executed by the processor to perform the steps of the method according to any one of claims 1-8.

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