Planar Magnetics Clip Mounting for High-Shock PCB Attachment
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Solution Overview
Problem
The manual assembly of large power devices like DC-DC transformers and inductors to circuit boards is time-consuming, costly, and induces thermal expansion stresses, while also failing to withstand high shock loads.
Innovation Solution
A winding assembly comprising a ferrite core, retaining clip, and spring clip, which is mechanically attached to a printed wiring board using threaded inserts and hooks, allowing for secure coupling and minimizing thermal stresses through spacers and pads with high-temperature materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual assembly is used to heat sink and solder large power devices to circuit boards, then the devices can be attached to the circuit board, but the assembly process is time-consuming, high in cost, and creates thermal expansion stresses in the components
Solution Approach 1:
The attachment system is segmented into multiple functional components: a retaining clip with feet for mechanical retention, a spring clip with feet for applied pressure, threaded inserts for secure mounting, and spacers for thermal management. This segmentation allows each component to perform its specific function efficiently, enabling automated assembly while maintaining high reliability and reducing thermal stresses through proper force distribution and thermal isolation.
2Strength
If manual soldering is used to attach large power devices, then the devices are securely attached, but the process is costly and creates thermal expansion stresses during heat sinking and soldering
Solution Approach 1:
The patent replaces the traditional thermal soldering process with a purely mechanical attachment system. The spring clip applies continuous mechanical pressure to secure the power device, while threaded inserts provide robust mechanical anchoring to the circuit board. This mechanical substitution eliminates the need for high-temperature soldering, reducing manufacturing complexity and avoiding thermal expansion stresses while maintaining strong attachment.
Solution Approach 2:
The retaining clip and spring clip act as intermediary components between the large power device and the circuit board. These intermediaries distribute mechanical loads and provide a compliant interface that accommodates thermal expansion without transmitting excessive stresses to the solder joints or circuit board, thereby strengthening the overall attachment while simplifying the manufacturing process.
3Reliability
If traditional attachment methods are used, then devices can be mounted, but they fail to withstand high shock loads
Solution Approach 1:
The spring clip introduces dynamic compliance to the attachment system. The spring mechanism can elastically deform under shock loads, absorbing impact energy and maintaining continuous contact pressure on the power device. This dynamic response allows the attachment to withstand high shock loads while the overall structural complexity remains manageable through the use of simple, standardized clip components.
Solution Approach 2:
The attachment system combines multiple materials with complementary properties: the spring clip uses elastic material for shock absorption, the retaining clip uses rigid material for structural support, and the feet use compliant material for stress distribution. This composite approach enhances shock resistance by leveraging the strengths of different materials while keeping the attachment structure relatively simple and modular.
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
The solution provides a reliable, low-cost attachment method that withstands high shock loads and minimizes thermal expansion stresses, ensuring secure and efficient coupling of large power devices to circuit boards.
Implementation Method 1
a spring clip positioned at least partially over the cover of the ferrite core. The spring clip includes a third foot and a fourth foot, wherein the third foot and the fourth foot are positioned adjacent the surface of the printed wiring board
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
A winding assembly, such as a transformer or an inductor, includes a spring clip and a retaining clip for mechanically coupling the winding assembly to a printed circuit board (PCB) or a printed wiring board (PWB). The clips provide structural rigidity to the winding assembly, allowing the winding assembly to remain functional during high shock events. Further, the clips compress a thermal pad positioned beneath the winding assembly, providing sufficient heat transfer surface area for transferring heat away from the winding assembly.