Multi-Step Molded Inductor Assembly for Higher Yield
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Solution Overview
Problem
Existing injection molding methods for high-power inductor devices in automotive applications result in low yield rates due to the complex structure and small gaps between the coil and magnetic core, which require high injection pressure and can damage the magnetic core.
Innovation Solution
A forming method for inductor devices that involves multiple injection molding steps, where the first inductor coil and magnetic core column are fixed together initially with a lower injection pressure, followed by injection molding of the magnetic yoke column assembly and finally the inductor injection-molded body to secure all components in place.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high injection pressure is used to ensure adequate filling of the molding material fluid in the injection molding process, then the filling completeness is improved, but the magnetic core is susceptible to damage resulting in low yield rate
Solution Approach 1:
The injection molding process is divided into multiple stages with different injection pressures. The first injection molding forms the coil assembly with lower pressure, and the second injection molding forms the final inductor device structure. This segmentation allows adequate filling without subjecting the magnetic core to excessively high pressure that would cause damage.
Solution Approach 2:
The coil assembly is preliminarily formed through the first injection molding process, creating a pre-structure that maintains the coil shape and positioning. This preliminary action enables the subsequent second injection molding to complete the device structure without requiring the magnetic core to withstand the full injection pressure from the beginning.
2Temperature
If the encapsulation process uses thermally conductive silicone gel to secure the inductor coil and magnetic core, then the thermal conduction and mechanical fixation are improved, but the encapsulation process becomes complex resulting in low forming efficiency
Solution Approach 1:
The encapsulation function is merged into the injection-molded body structure itself. The injection-molded body simultaneously provides mechanical fixation of the coil and magnetic core, structural support, and thermal conduction pathways. This eliminates the need for separate encapsulation materials like silicone gel and simplifies the overall manufacturing process.
Solution Approach 2:
The injection-molded body performs multiple functions: it secures the inductor coil and magnetic core in place, provides structural support for the entire device, and conducts heat away from the magnetic core and coil. This multi-functionality replaces what would otherwise require multiple separate components and processes.
3Reliability
If the inductor device has a complicated structure with small gaps between the coil and internal magnetic core, then the electromagnetic performance is improved, but the injection molding process requires high pressure causing magnetic core damage
Solution Approach 1:
The manufacturing process is segmented into two injection molding operations. The first operation forms the coil assembly with the gap structure already in place, preserving the electromagnetic performance. The second operation adds the remaining structural components without requiring high pressure that would damage the magnetic core, thus managing the complexity of the overall structure.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method reduces the risk of damage to the magnetic core by applying lower injection pressures during initial fixation, enhances assembly efficiency through positioning structures, and increases the overall yield rate of inductor devices.
Implementation Method 1
a first injection-molded body, with the first inductor coil wound around an outer perimeter of the first magnetic core column, the first inductor coil and the first magnetic core column secured in place by the first injection-molded body, and at least a part of the first injection-molded body filling a gap between the first inductor coil and the first magnetic core column
Implementation Method 2
a magnetic yoke column assembly comprising a magnetic yoke column and a magnetic yoke column injection-molded body, with the magnetic yoke column injection-molded body having a first assembly positioning structure for positioning the first assembly; an inductor injection-molded body, and an end magnetic yoke that is arranged at an end of the magnetic yoke column, wherein a magnetic circuit between the first magnetic core column and the magnetic yoke column is conducted through the end magnetic yoke
Data Source
AI summary
The present disclosure relates to the field of inductor, specifically to an inductor device and a forming method therefor. The injection-molded body of the inductor device is formed through multiple injection molding steps. The first inductor coil and the first magnetic core column are fixed together in advance, and the injection pressure required for the first injection-molded body is lower than that for the entire inductor device. Similarly, the magnetic yoke column also experiences reduced injection pressure. Finally, when fixing the first assembly and the magnetic yoke column assembly in place by the inductor injection-molded body, due to the first injection-molded body having already fixed first magnetic core column and the first inductor coil, the overall anti-pressure ability of the first assembly is higher, enabling it to withstand greater injection pressure, resulting in a higher yield rate for the inductor device.