Gas Sensor Contact Member with Segmented Constraint Housing
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Solution Overview
Problem
Conventional gas sensors experience asymmetrical force distribution during the retention of sensor elements, leading to potential local contact failures and unstable electric continuity due to the C-shaped fixing metal fixture's elasticity.
Innovation Solution
A gas sensor design featuring a constraint member constructed by a first and second member with engaging mechanisms, where the engaging parts are provided on one member and the engaged parts on the other, allowing for uniform and stable contact between the contact point members and electrode terminals, and utilizing an annular member to deform and pinch the sensor element, preventing displacement and reaction forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a C-shaped fixing metal fixture is used to retain the sensor element, then the sensor element can be fixed in the insertion port, but the elastic force distribution becomes asymmetrical causing local contact failures
Solution Approach 1:
The fixing metal fixture is divided into a first member and a second member that can be separated. Each member has engaging parts that work together to constrain the housing members. This segmentation allows the constraint function to be distributed symmetrically, eliminating the asymmetrical force distribution problem of the C-shaped fixture while maintaining the retention function.
Solution Approach 2:
The engaging parts are specifically designed with asymmetric geometries that complement each other between the first and second members. The engaging part of the first member engages with the engaged part of the second member in a manner that creates symmetrical constraint forces on the housing members, resolving the original asymmetry problem.
2Manufacturing precision
If the fixing metal fixture constrains the housing members during assembly, then the housing members are positioned correctly, but reaction forces are generated that may cause displacement
Solution Approach 1:
The constraint system is designed to be dynamic rather than rigid. The engaging parts allow controlled movement and adjustment during the assembly process, enabling the housing members to be positioned correctly while accommodating assembly tolerances. This reduces the generation of harmful reaction forces that would occur with a rigid constraint system.
3Reliability
If the contact point member energizes the electrode terminal with elastic force, then electric continuity is achieved, but the contact pressure is non-uniform due to fixture asymmetry
Solution Approach 1:
The first and second members together form a universal constraint system that provides both positioning and force distribution functions. By distributing the constraint function across two members with complementary engaging parts, the system ensures uniform contact pressure is applied to all electrode terminals, improving the reliability of electric continuity.
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 design ensures a stable and uniform electric connection between the sensor element and the contact member, preventing local contact failures and ensuring consistent contact pressure, thereby enhancing the reliability of the gas sensor.
Implementation Method 1
an annular member to deform and pinch the sensor element, preventing displacement and reaction forces
Implementation Method 2
the elastic force of the pressing spring acts on the housing via the fixing metal fixture with the caulking ring being caulked, whereby the sensor element is fixed to the housing
Data Source
Figure 1(a)~1(b)
Figure 2
Figure 3(a)~3(c)
AI summary
To provide a gas sensor which can stably carry out a securement of an electric continuity between a sensor element and a contact member. A contact member for a gas sensor in which an electric connection to a sensor element is obtained by pinching and fixing the sensor element in an inserting port formed by a pair of housing members includes a constraint member which is provided in an outer periphery of a pair of housing members and has a constraining function of constraining a displacement of a pair of housing members within a predetermined range. The constraint member constrains a displacement of a pair of housing members within a predetermined range before the sensor element is pinched and fixed by a pair of housing members, and exists in a state of being pinched between the annular member and a pair of housing member without generating any reaction force with respect to the external force, after the sensor element is pinched and fixed.