Reactor Core Piece Geometry to Reduce Voids and Vibration Cracking
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Solution Overview
Problem
The manufacturing process of composite material core pieces often results in voids due to uneven solidification rates, which can lead to cracking when these core pieces are subjected to vibration in reactors, affecting the stability and performance of reactors, converters, and power conversion devices.
Innovation Solution
The core pieces are designed with specific hole or groove portions that reduce the difference in solidification rates, minimizing void formation by ensuring the radius of the inscribed circle in the middle core portion is less than or equal to 0.6 times the radius of the reference inscribed circle, thereby reducing the likelihood of cracking due to vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a composite material molded body is used for the core piece, then ease of manufacture is improved, but voids are generated due to uneven solidification rates
Solution Approach 1:
The invention introduces hole portions or groove portions at specific locations within the middle core portion to locally modify the solidification behavior. These structural features create preferential cooling paths that equalize the solidification rate across different regions of the molded body, preventing void formation while maintaining the ease of composite material manufacturing
Solution Approach 2:
The invention changes the geometric parameters of the core piece by introducing hole portions or groove portions with specific dimensions. The radius of the first inscribed circle is controlled to be less than or equal to 0.6 times the radius of the reference inscribed circle, which optimizes the solidification rate distribution and prevents void formation
2Ease of manufacture
If voids are present in the core piece, then manufacturing is simplified, but cracking occurs under vibration affecting reliability
Solution Approach 1:
The hole portions or groove portions are strategically positioned in the middle core portion to specifically address the solidification rate difference problem without complicating the overall manufacturing process. This localized structural modification eliminates the root cause of void formation while maintaining manufacturing simplicity
Solution Approach 2:
The invention proactively prevents void formation by designing hole portions or groove portions that equalize solidification rates before voids can form. This preventive approach eliminates the precursor conditions for cracking, thereby enhancing reliability without adding complex post-processing steps
Data Source
AI summary
A core piece includes a middle core portion configured to be arranged inside a coil, and an end core portion configured to face an end face of the coil. The middle core portion includes a hole portion or a groove portion extending in an axial direction of the coil. In a lateral cross-section of the middle core portion, a radius of a first inscribed circle is less than or equal to 0.6 times a radius of a reference inscribed circle. The lateral cross-section is a cross-section of the middle core portion passing through the hole portion or the groove portion along a plane orthogonal to the axial direction of the coil. The first inscribed circle is a largest inscribed circle between an outline of the hole portion or the groove portion in the lateral cross-section and a peripheral outline of the middle core portion in the lateral cross-section.