Segmented Case Unit for Coil Devices in EV Power Converters
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Solution Overview
Problem
Existing electronic devices in power converters for hybrid and electric vehicles face issues with potting resin cracking and inadequate heat dissipation due to thermal stress and mechanical vibration, leading to poor fixing of coil devices and increased production costs from complex metal case designs.
Innovation Solution
A case unit comprising a first case with an annular portion for the coil and legs, and a second case with a cylindrical portion that engages the first case, both with fixing portions for secure attachment to a substrate, reducing resin cracking and simplifying assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the side walls of the metal case have large raggedness to increase adhesion with the potting resin, then the adhesion between the metal case and the potting resin is improved, but the metal case has a complicated shape and thus the production cost increases
Solution Approach 1:
The invention divides the case into two separate parts: a metal case and a resin case. The resin case is segmented into multiple pieces that are arranged around the coil device, with each piece having a relatively simple shape. This segmentation allows the adhesion function to be distributed across multiple simple components rather than requiring one complex component with ragged surfaces, thereby resolving the contradiction between adhesion strength and shape complexity.
2Reliability
If the coil device is fixed by a potting resin in a metal case, then the coil device is contained and protected, but cracking occurs in the potting resin or its boundary with the metal case due to thermal stress and mechanical vibration, resulting in insufficient heat dissipation and damaged fixing
Solution Approach 1:
The invention introduces a resin case as an intermediary component between the coil device and the metal case. This resin case serves as a mediator that absorbs and distributes thermal stress and mechanical vibration, preventing direct stress concentration at the boundary between the potting resin and the metal case. The resin case's flexibility and thermal properties make it an ideal intermediary that maintains the integrity of the potting resin while ensuring reliable fixing of the coil device.
3Strength
If a single metal case with complex shape is used to contain the coil device, then the adhesion with potting resin is improved, but the assembly process becomes complicated and production cost increases
Solution Approach 1:
The case structure is segmented into a metal case and multiple resin case pieces. Each resin case piece has a simple geometry that is easy to manufacture, and the pieces are designed to be assembled around the coil device in a straightforward sequence. This segmentation transforms a complex single-piece manufacturing challenge into a series of simple assembly operations, thereby improving ease of manufacture while maintaining adequate adhesion through the combined surface area of multiple pieces.
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 ensures reliable fixing and reduced resin cracking, enhancing heat dissipation and assembly efficiency, making it suitable for high-voltage and large-current applications in vehicles.
Implementation Method 1
a potting resin filling the second case for fixing the coil device to the second case
Implementation Method 2
a first fixing portion of each leg of the first case and each second fixing portion of the second case being overlapped and fixed to a substrate
Data Source
AI summary
A case unit for containing an annular magnetic core and a coil, which comprises a first case having an annular portion having an annular space for receiving the annular magnetic core, around which the coil is wound, and pluralities of legs extending from the annular portion to one side; and a second case engaging the first case, such that it enters gaps between the annular portion and legs of the first case, and covers part of the annular portion from the one side; a first fixing portion of each leg of the first case and each second fixing portion of the second case being overlapped and fixed to a substrate.