Current Detection Apparatus Non-Parallel Recessed Casing
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Solution Overview
Problem
Current detection apparatuses in vehicles face challenges in visually inspecting soldering failures due to limited clearance, leading to potential thermal and mechanical fatigue issues, and increasing product size to address this is not desirable in the automotive field.
Innovation Solution
A current detection apparatus with a recessed portion in the casing that allows the circuit board to be mounted without raising the entire board, enabling visible inspection of solder junctions through a non-parallel engagement section, preventing product size increase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If the circuit board is raised above the level of the cover-mounting surface to enable visual inspection of solder junctions, then the inspectability of soldering quality is improved, but the product size increases
Solution Approach 1:
The recessed portion is configured with its bottom surface at a lower level than the cover-mounting surface, creating a vertical dimension difference that allows the circuit board to be positioned for inspection without raising the overall product height. The open end of the recessed portion provides access to view the solder junction from the front side, resolving the contradiction between inspectability and compact size.
2Volume of moving object
If the circuit board is positioned lower than the cover-mounting surface with small clearance, then the product size is reduced, but the visual inspection of soldering failure becomes impossible
Solution Approach 1:
The casing is segmented into a recessed portion and a cover portion, with the recessed portion providing a dedicated space for the circuit board. This segmentation allows the circuit board to be positioned in a way that enables inspection of the solder junction between the terminal and the circuit board, while maintaining overall compact dimensions.
3Ease of manufacture
If poor solder rise occurs with less than 100% solder fill, then the manufacturing process is simplified, but the thermal fatigue resistance and mechanical fatigue strength are reduced
Solution Approach 1:
The recessed portion structure enables self-inspection of the solder junction quality without requiring additional inspection equipment or disassembly. The visual accessibility of the solder junction allows operators to verify proper solder fill and rise during or after assembly, ensuring manufacturing quality while maintaining process simplicity.
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
Facilitates easy visual inspection of soldered conditions without increasing product size, enhancing reliability and maintainability while maintaining thermal and mechanical integrity.
Implementation Method 1
a current detection circuit for detecting a current flowing through the resistor on the basis of a potential difference between two positions along the current carrying member
Implementation Method 2
a solder fillet covers the whole land on a rear-side surface opposite to an front-side surface (as a soldering surface) of the circuit board, resulting from a solder-rising phenomenon in which the solder rises along the through-hole from the front-side surface to the rear-side surface of the circuit board
Data Source
AI summary
A current detection apparatus for detecting a current from a battery flowing through a harness. The apparatus includes a resistor having a current carrying member disposed between a terminal of the battery and the harness, a circuit board provided thereon with a current detection circuit for detecting a current flowing through the resistor, and a casing having a recessed portion for accommodating the circuit board, a cover for closing an opening of the recessed portion. The circuit board includes a solder junction between the circuit board and a terminal protruding from an inside bottom of the recessed portion and passing through a through hole arranged on the circuit board, and an open end of the recessed portion that can be engaged with the cover is non-parallel to the circuit board so that at least a portion of the circuit board including the solder junction lies outside of the recessed portion.