Gas Sensor Terminal Unit Stabilizes Contact Pressure
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Solution Overview
Problem
The existing gas sensors face issues with reduced contact pressure between metal terminals and electrode pads due to relative movement during assembly, leading to variations in electrical resistance and decreased detection accuracy.
Innovation Solution
A gas sensor design featuring a terminal unit with proximal end insulators and a spring member that presses the insulators together, ensuring stable contact between metal terminals and electrode pads, with the insulator contact portions located closer to the sensor element than the terminal contact portions to maintain consistent electrical conduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the proximal end insulators are separated from each other, then the assembly process is simplified, but the metal terminals tend to move relative to the electrode forming surfaces causing reduced contact pressure
Solution Approach 1:
The spring member is pre-installed between the proximal end insulators to apply continuous contact pressure before assembly is completed. This preliminary action ensures that the metal terminals maintain stable contact with the electrode pads throughout the assembly process and operation, preventing relative movement and contact pressure reduction.
Solution Approach 2:
The spring member introduces a dynamic elastic force that automatically compensates for any relative movement between the metal terminals and electrode forming surfaces. This dynamic mechanism maintains constant contact pressure even when external forces are applied during assembly or operation.
2Productivity
If the metal terminals are connected to leads or bush installed during assembly, then the sensor becomes functional, but the contact pressure of metal terminal to electrode pad is significantly reduced
Solution Approach 1:
The spring member applies contact pressure in advance before the metal terminals are connected to leads or before the bush is installed. This ensures that even when these components are attached during assembly, the metal terminals maintain sufficient contact pressure with the electrode pads, preventing detection accuracy degradation.
Solution Approach 2:
The spring member acts as a cushioning element that compensates for the contact pressure reduction caused by subsequent assembly steps. By providing elastic force beforehand, it ensures stable electrical contact is maintained even when external forces are applied during lead connection or bush installation.
3Reliability
If the insulator contact portions are positioned closer to the sensor element, then the electrical conduction is stabilized, but the structure becomes more complex
Solution Approach 1:
The solution addresses the positioning requirement by utilizing the longitudinal dimension of the insulators. By extending the insulator length and positioning the contact portions at specific locations along this dimension, the design achieves stable electrical conduction without adding complexity in other dimensions or requiring additional components.
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 stabilizes electrical conduction between electrode pads and metal terminals, preventing contact pressure variations and maintaining detection accuracy even under external forces during assembly.
Implementation Method 1
a spring member pressing the pair of the proximal end insulators in a direction that the proximal end insulators approach each other
Implementation Method 2
stabilizes electrical conduction between electrode pads and metal terminals
Implementation Method 3
the heater including a heat generating section to generate heat for heating the sensor cell
Data Source
AI summary
The gas sensor includes a sensor element having electrode pads formed in its electrode forming surfaces at the proximal end portion thereof, an insert-holding insulator insert-holding the sensor element, a housing insert-holding the insert-holding insulator, and a terminal unit. The proximal end portion of the sensor element is held by the terminal unit which includes a pair of proximal end insulators formed with metal terminals at their inner surfaces, and a spring member pressing the proximal end insulators in a direction that they approach each other. Each of the proximal end insulators includes an insulator contact portion in contact with one of the electrode forming surfaces. The insulator contact portion is located closer to the proximal end of the sensor element than a terminal contact portion at which the metal terminal contacts a corresponding one of the electrode pads.