Current Sensor Chamfered Corners Stress Concentration
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Solution Overview
Problem
Current current sensors face challenges in effectively managing electric field and stress concentrations at corners, which can lead to durability issues and increased risk of cracks, particularly under temperature variations.
Innovation Solution
The current sensor design incorporates chamfered corners in critical areas, such as the conductive portion and lead frames, to reduce electric field and stress concentrations. This design utilizes a mold resin with a high filler content to further enhance durability by obstructing discharge paths and increasing the toughness of the material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional corner design is used in current sensor, then manufacturing is simpler, but electric field and stress concentrations increase leading to durability issues
Solution Approach 1:
The patent applies asymmetry by replacing conventional symmetric 90-degree corners with chamfered corners having asymmetric angles (e.g., 45 degrees on one side, 30 degrees on the other). This asymmetric design redistributes electric field and mechanical stress more uniformly across the corner region, eliminating concentration points while maintaining structural integrity and improving durability without significantly complicating manufacturing.
2Reliability
If standard mold resin is used, then material application is easier, but crack propagation resistance is insufficient under temperature variations
Solution Approach 1:
The patent employs composite materials by formulating mold resin containing dispersed filler particles (such as silica or other inorganic fillers) within the polymer matrix. This composite structure enhances crack propagation resistance through mechanisms like crack deflection and energy absorption at filler-matrix interfaces, while the fillers also improve thermal stability. The composite resin maintains ease of manufacture through standard injection molding processes.
Solution Approach 2:
The patent applies parameter changes by modifying the mold resin's physical and chemical properties, specifically adjusting filler content concentration, particle size distribution, and crosslinking density. These parameter modifications enhance the resin's toughness and thermal expansion characteristics to match surrounding components, improving crack resistance under temperature cycling while preserving manufacturability through controlled material formulation.
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 chamfered corner design significantly reduces electric field and stress concentrations, thereby enhancing the durability of the current sensor and preventing cracks. The use of high-filler-content mold resin further improves reliability by making it more difficult for cracks to propagate.
Implementation Method 1
at least one magnetoelectric conversion element
Data Source
AI summary
A current sensor includes a first lead frame having a first terminal portion and a conductive portion coupled to the first terminal portion, wherein a measurement current measured by the at least one magnetoelectric conversion element flows through the first terminal portion and the conductive portion; and a signal processing IC that processes a signal output from the at least one magnetoelectric conversion element, arranged on a second surface side opposing a first surface of the conductive portion, having a circuit surface with the at least one magnetoelectric conversion element arranged thereon. The conductive portion has a first corner between a first end surface opposing a side coupled to the first terminal portion and a second surface facing the signal processing IC, and a second corner between the first end surface and a first surface opposing the second surface facing the signal processing IC.