Welded Sensor Device Sealing via Peripheral Welding
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Solution Overview
Problem
Conventional sensor device assembly structures face challenges in ensuring high environmental resistance and long-term sealing performance due to tolerance accumulation in parts, which affects miniaturization and design, especially in harsh environments with corrosive agents.
Innovation Solution
A sensor device configuration featuring a casing, cover member, and fixing cover with welded portions outside the cover member, where the gasket is positioned between the cover member and the casing, and the fixing cover presses the cover member toward the casing, utilizing a resilient force to enhance sealing and reduce tolerance-related issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If snap fit assembly structure with engagement tab and hole is used to fix the cover member to the casing, then the assembly process is simplified, but tolerance accumulation occurs leading to poor sealing performance and inability to ensure high environmental resistance
Solution Approach 1:
The patent replaces the mechanical snap fit assembly structure with a welding connection structure. The fixing cover is welded to the casing at multiple positions, eliminating the engagement tab and hole mechanism. This substitution of mechanical assembly with welding connection resolves the tolerance accumulation issue while maintaining ease of manufacture through automated welding processes.
Solution Approach 2:
The patent divides the welding connection into multiple discrete welding positions distributed around the periphery of the cover member. Instead of a single connection point, multiple welding positions are provided to distribute stress and prevent deformation of the gasket, thereby ensuring reliable sealing performance.
2Reliability
If the gasket size is increased to absorb dimensional variation and ensure sealing performance, then sealing reliability improves, but the sensor device cannot be miniaturized
Solution Approach 1:
By replacing the mechanical snap fit system with welding connection, the patent eliminates the need for oversized gaskets to compensate for tolerance accumulation. The welding connection provides precise and stable positioning, allowing the use of compact gaskets that fit within limited space, thereby enabling miniaturization of the sensor device while maintaining sealing reliability.
3Strength
If the fixing cover is designed with sufficient length from the cover member to the engagement tab to firmly fix against gasket resilience, then fixation strength improves, but the external design is impaired
Solution Approach 1:
The patent replaces the long-distance mechanical engagement structure with localized welding connections. The welding positions are arranged around the periphery of the cover member, providing sufficient fixation strength through distributed welding points without requiring the fixing cover to extend far from the cover member, thus preserving the external design.
Solution Approach 2:
Instead of extending the fixing cover in one dimension (length) to achieve fixation strength, the patent distributes welding positions in a two-dimensional arrangement around the periphery of the cover member. This dimensional change allows sufficient fixation strength to be achieved within a compact form factor that does not compromise external design.
4Reliability
If multiple welding portions are provided at distant locations outside the cover member, then tolerance accumulation is reduced and gasket resilience is maintained, but the manufacturing complexity increases
Solution Approach 1:
The patent replaces the complex mechanical assembly structure with welding connections. Although multiple welding positions are provided, welding is a standardized manufacturing process that can be easily automated, thereby reducing overall manufacturing complexity compared to precision mechanical assembly of engagement tabs, holes, and gaskets.
Solution Approach 2:
The welding connection is segmented into multiple discrete welding positions around the periphery. This segmentation allows for distributed stress management and prevents gasket deformation while maintaining a relatively simple overall structure. The segmented welding approach can be efficiently implemented through automated welding processes.
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 achieves stable high sealing performance over a long period with reduced volume requirements, minimizing the impact of part tolerances and allowing for miniaturization while maintaining design integrity, even in severe environments.
Implementation Method 1
The gasket is interposed between the cover member and a portion of the casing located at a peripheral edge of the opening, to surround the opening. The fixing cover presses the cover member toward the casing and thus holds the cover member to bring the gasket into close contact with the casing and the cover member.
Implementation Method 2
a plurality of welded portions bonding the casing and the fixing cover together are provided in a region outside the cover member such that the welded portions are distant from each other
Data Source
AI summary
A sensor device includes: a casing provided with an opening; a cover member covering the opening; a gasket interposed between the cover member and the casing; and a fixing cover which fixes both the gasket and the cover member to the casing. A plurality of welded portions bonding the casing and the fixing cover together are provided in a region outside the cover member such that the welded portions are distant from each other.