Resin-Molded Current Detector Core Gaps
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Solution Overview
Problem
The challenge is to maintain the pairing of core pieces with consistent cross-sectional areas and magnetic characteristics in electric current detectors, especially when using wound cores with varying winding strengths and annealing stresses, which can lead to asymmetric pieces and decreased magnetic permeability.
Innovation Solution
A core design with multiple gaps formed in an annular core main body, where resin partial moldings cover the gaps to maintain the core's integrity and prevent separation, along with a method of forming these gaps and moldings to ensure consistent pairing and magnetic stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple gaps are formed in a wound core main body, then magnetic saturation characteristics are improved, but core pieces loosen and cross-sectional areas vary due to residual stress
Solution Approach 1:
The patent applies preliminary action by forming gaps in the core main body before the core pieces are fully assembled and fixed. By creating the gaps in advance while the core structure is still intact and constrained, the residual stress from winding and annealing is distributed uniformly, preventing subsequent loosening and maintaining consistent cross-sectional areas opposite the gaps.
2Reliability
If gaps are formed at non-center positions to adjust magnetic characteristics, then magnetic permeability is modified, but asymmetric core pieces are produced requiring complex pairing
Solution Approach 1:
The patent deliberately applies asymmetry by forming gaps at non-center positions in the core main body. This asymmetric gap placement allows precise control over magnetic permeability and saturation characteristics. The method manages the resulting asymmetric core pieces through a systematic pairing process that matches pieces from the same core, transforming the complexity into a controlled manufacturing feature rather than a defect.
3Manufacturing precision
If core pieces are cut from different core main bodies to maintain pairing, then consistency is improved, but manufacturing complexity and difficulty increase
Solution Approach 1:
The patent applies segmentation by dividing the core main body into multiple core pieces through controlled gap formation. This segmentation allows each piece to be individually managed while maintaining their original pairing relationships. The process transforms a complex pairing problem into a systematic segmentation and reassembly operation, improving consistency without excessively complicating manufacturing.
Data Source
AI summary
A core for an electric current detector comprises a pair of first and second core pieces (20), (23), wherein the first core piece has first opposed surfaces (21), (21) and the second core piece has second opposed surfaces (24), (24), the first and second opposed surfaces face to each other with a spacing between a first gap (26) and a second gap (28), respectively, and the first and second core pieces are covered by a resin-made first partial mold (30) on the area near and inclusive of the first gap and are covered by a resin-made second partial mold (40) on the area near and not inclusive of the second gap, wherein the second partial mold includes a second-1 molded member (41) on the first core piece side and a second-2 molded member (42) on the second core piece side.