Gas Sensor Contact Spring Design for Size Reduction
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Solution Overview
Problem
Existing gas sensors face challenges in reducing the size or thickness of electrical terminals while maintaining mechanical strength due to tension stresses applied during installation, which complicates the reduction of overall sensor size.
Innovation Solution
The design incorporates a specific contact spring with a spring contact portion, holding portion, bent portion, and connecting portion, where the spring bent portion is bent inwardly and extends in a slant form to distribute external forces as residual stress, preventing tensile stress concentration and allowing for reduced size and thickness of contact springs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the electrical terminals are increased in size or thickness to maintain mechanical strength under tension stress, then the mechanical strength is improved, but the overall size of the gas sensor increases
Solution Approach 1:
The electrical terminal is divided into multiple functional segments: a crimp portion for joining lead wires, a terminal connecting portion for contacting electrode terminals, and a stress concentration portion that acts as a mechanical buffer. This segmentation allows each part to be optimized independently, enabling size reduction while maintaining overall strength through strategic stress distribution.
Solution Approach 2:
The stress concentration portion is pre-designed with specific geometric features (reduced cross-section area) to anticipate and prepare for the tension stresses that will be applied during installation and operation. This preliminary structural preparation allows the terminal to naturally distribute stresses before they reach critical levels, preventing the need for overall size increase.
2Volume of moving object
If the electrical terminals are reduced in size or thickness to decrease overall sensor size, then the overall size of the gas sensor is reduced, but the mechanical strength of the electrical terminal deteriorates
Solution Approach 1:
Instead of uniformly reducing the entire electrical terminal size, the invention applies local quality changes by creating a stress concentration portion with specifically reduced cross-section area at a strategic location. This localized modification allows the terminal to maintain adequate strength in critical areas while reducing overall size, as the stress concentration portion is positioned to handle tensile stresses before they propagate to the crimp and connecting portions.
3Volume of moving object
If the cross-sectional area of the electrical terminal is reduced to minimize size, then the size is reduced, but the ability to withstand tension stress deteriorates
Solution Approach 1:
The stress concentration portion is pre-configured with a reduced cross-sectional area to create a controlled weak point that will yield first under tension stress. This preliminary design ensures that when tension forces are applied during installation or operation, the stress is naturally concentrated in this predetermined area, protecting the crimp portion and terminal connecting portion from excessive forces even when the overall terminal size is reduced.
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
This configuration ensures the mechanical strength of the contact springs is maintained, enabling them to be reduced in size and thickness without compromising performance, even under external forces from installation and operation.
Implementation Method 1
the spring bent portion is bent inwardly from the spring holding portion and extends in a slant form in the contacting direction. The spring bent portion is retained by the porcelain insulator.
Data Source
AI summary
A sensor includes contact springs placed in contact with electrode terminals on major surfaces of a sensor device. At least one of the contact springs includes a spring contact portion, a spring holding portion, a spring bent portion, and a spring connecting portion. The spring contact portion contacts an outer surface of one of the electrode terminals. The spring holding portion is turned from the spring contact portion and extends outside the spring contact portion so as to overlap the spring contact portion in the contacting direction. The spring bent portion is bent inwardly from the spring holding portion and extends at a given angle to the contacting direction. The spring connecting portion is bent from the spring bent portion and extends in the axial direction of the sensor. Such a structure enables the contact spring to be reduced in size and thickness without sacrificing a required mechanical strength thereof.