Gas Sensor Assembly Switching Holding State for Warped Elements
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Solution Overview
Problem
The assembly of gas sensors with ceramic sensor elements is hindered by warping issues and tight dimensional tolerances, leading to interference and poor airtightness, particularly in automated processes, where securing clearance is challenging due to the need for size reduction and hermetic sealing.
Innovation Solution
A method and apparatus that utilize a holder with clamping mechanisms to switch the sensor element's orientation during assembly, allowing for reliable annular mounting of ceramic supporters and powder compacts despite warping, by fitting through holes with precision and minimizing the outside diameter of the intermediate assembly product for secure tubular body mounting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the inside diameter of the inner tube and sizes of ceramic supporters and powder compacts are reduced to minimize sensor size, then the size of the gas sensor is minimized, but the clearance between fitting parts becomes insufficient causing interference and poor assembly
Solution Approach 1:
The invention makes the holding state of the sensor element switchable between upper-side held state and lower-side held state. By dynamically changing which end is held and the orientation of the element during assembly, the system can accommodate variations in sensor element shape (including warping) while maintaining proper clearance and fit between components.
Solution Approach 2:
The invention changes the holding position parameter from fixed (conventional single-point holding) to variable (switchable between upper-side and lower-side holding). This parameter change allows the assembly system to adapt to different sensor element configurations and maintain appropriate clearance even when component dimensions are minimized.
2Reliability
If dimensional tolerance is set smaller than typical fitting parts to improve hermetic sealing, then airtightness between measurement gas space and reference gas space is improved, but interference between parts occurs making assembly difficult
Solution Approach 1:
By making the holding state switchable, the system can dynamically adjust to maintain proper alignment and clearance during assembly even with tight tolerances. The ability to switch between holding the upper side or lower side of the sensor element provides flexibility to accommodate dimensional variations while maintaining hermetic sealing.
3Productivity
If automated assembly is implemented to improve productivity, then assembly efficiency is improved, but interference between parts due to warping and tight tolerances causes poor assembly quality
Solution Approach 1:
The switchable holding state mechanism enables automated assembly by providing a systematic method to handle sensor elements with warping and tight tolerances. The automation system can switch between holding states to accommodate variations in each sensor element, ensuring proper assembly quality while maintaining high productivity.
Solution Approach 2:
The system incorporates feedback by monitoring the fitting process and switching holding states based on the actual condition of the sensor element and annular mounting member. This feedback mechanism ensures that automated assembly maintains high precision even when dealing with dimensional variations and warping.
Data Source
AI summary
Provided are a method of reliably assembling a gas sensor. A plurality of annular mounting members are repeatedly subjected to following steps: bringing a sensor element into an upper-side held state in which the element is held such that an upper end thereof extends vertically with a lower end thereof being inserted into a recess; fitting a through hole of an annular mounting member with the upper end of the element brought in to the upper-side clamped state; and switching from the upper-side held state to a lower-side held state in which the element is held such that the lower end thereof extends vertically, to thereby cause the annular mounting member to reach a predetermined annularly mounting position. Then, the resultant intermediate assembly product is sandwiched by a centering device to minimize the outside diameter thereof, and thereafter, a tubular body is annularly mounted to the intermediate assembly product.