Gas Sensor Terminal Positioning via Protruding Separator
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Solution Overview
Problem
The assembly of oxygen sensors is hindered by the difficulty in accurately positioning outer and inner connection terminals due to slight play and radial displacement caused by marginally dimensioned through holes in the separator, leading to potential crushing of terminal components and defective sensor assembly.
Innovation Solution
A gas sensor subassembly unit with a cylindrical sensor element, connection terminals, and a separator featuring protruding portions that provide a biasing force for secure fitting of the terminals, preventing positional displacement and ensuring accurate positioning, even during automated assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the dimensions of the through holes are set with some margin for ease of insertion, then the ease of manufacture is improved, but the positioning precision of the connection terminals deteriorates
Solution Approach 1:
A positioning pin is introduced as an intermediary component between the separator and the connection terminal. The positioning pin fits into a positioning hole in the separator and engages with a positioning groove on the connection terminal, thereby ensuring accurate positioning without requiring tight tolerances on the through holes themselves. This mediator enables both easy insertion and precise positioning.
Solution Approach 2:
The positioning function is segmented from the through hole structure. Instead of relying solely on the through hole dimensions for both insertion and positioning, the positioning function is separated into a dedicated positioning hole and positioning pin mechanism. This allows the through holes to be dimensioned for ease of insertion while the positioning pin ensures accurate terminal placement.
2Ease of manufacture
If the dimensions of the through holes are set with some margin, then the ease of manufacture is improved, but the connection reliability deteriorates due to radial displacement
Solution Approach 1:
The positioning pin acts as a mediator that prevents radial displacement of the connection terminal. By engaging the positioning groove on the terminal with the positioning pin, any radial movement is blocked, ensuring reliable electrical connection even when the through hole has generous dimensions for ease of manufacture.
3Productivity
If automated assembly is used to improve productivity, then the productivity is improved, but the positioning accuracy deteriorates due to play in the through holes
Solution Approach 1:
The positioning pin and positioning groove mechanism enables self-alignment during automated assembly. The positioning groove guides the connection terminal onto the positioning pin, allowing the components to self-position accurately without requiring high-precision robotic positioning. This self-service mechanism maintains positioning accuracy while enabling efficient automated assembly.
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 enables reliable and efficient assembly of gas sensors by preventing terminal displacement and crushing, reducing defective units and facilitating easy mounting while ensuring precise terminal placement.
Implementation Method 1
the fitting portion of the connection terminal is fixed to a radially lateral surface of the protruding portion under the action of a biasing force of the fitting portion
Data Source
AI summary
The present invention aims to provide a gas sensor that can favorably be assembled by proper positioning of a connection terminal relative to a separator and a subassembly unit for such a gas sensor. In an oxygen sensor, a separator has protruding portions formed on a surface of a front end part thereof; an outer connection terminal has an outer fitting portion fixed to outer circumferential surfaces of the protruding portions under its biasing force; and an inner connection terminal has an inner fitting portion fixed to inner circumferential surfaces of the protruding portions under its biasing force. Thus, it is less likely that the outer and inner connection terminals will be displaced in position relative to the separator and is possible to allow proper positioning of the outer and inner connection terminals.