Gas Sensor Separator Fixing via Metal Holder Welding
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Solution Overview
Problem
Conventional gas sensors experience vibration issues due to the separator not being fixed within the outer casing, leading to potential breakage of metal terminals from shear stress caused by external forces or vibrations.
Innovation Solution
A metal holder is used to surround and fix the separator to the outer casing through welding, reducing the likelihood of separator vibration and stress on metal terminals, while also simplifying the welding process and minimizing thermal expansion-related cracking and corrosion risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the separator is spaced apart from the outer casing without fixation, then the assembly process is simpler, but the separator vibrates relative to the outer casing under external force or vibration, causing stress on metal terminals and potential breakage
Solution Approach 1:
The fixing structure is divided into multiple discrete fixing portions (first fixing portion, second fixing portion, third fixing portion) distributed around the separator's outer peripheral surface. Each fixing portion independently secures the separator at different locations, preventing vibration without requiring a complete enclosing fixation structure. This segmented approach maintains assembly simplicity while achieving reliable separator stabilization.
2Reliability
If the separator is fixed to the outer casing, then vibration and stress on metal terminals are reduced, but the device complexity increases due to additional fixing structures
Solution Approach 1:
The fixing portions are integrated directly into the outer casing structure, merging the fixation function with the existing outer casing. The fixing portions protrude inward from the outer casing's inner peripheral surface, combining the support and fixation roles into a single structural element. This reduces overall device complexity by eliminating separate fixation components while maintaining reliable separator stabilization.
3Strength
If multiple members are welded together (metal holder, outer casing, metal shell), then the fixing strength is improved, but the welding process becomes more complex and thermal expansion-related cracking risk increases
Solution Approach 1:
The metal holder is extracted from the assembly, removing it entirely from the structure. Instead of using a separate metal holder component that would require welding to both the outer casing and metal shell, the fixing portions are formed directly on the outer casing. This eliminates the need for complex multi-member welding operations and associated thermal expansion cracking risks, while maintaining adequate fixing strength through the directly-formed fixing portions.
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
The solution effectively reduces separator vibration relative to the outer casing, prevents metal terminal breakage, and enhances the durability and corrosion resistance of the gas sensor.
Implementation Method 1
The metal holder is fixed to the outer casing by welding the outer casing contact portion to the outer casing
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A gas sensor (1) includes a sensor element (5), a metal shell (3), an outer casing (11), a metal terminal (41, 42, 43, 44), a separator (13), and a lead wire (31, 32, 33, 34). The gas sensor (1) further includes a metal holder (20) having a tubular shape extending in an axial direction (DX). The metal holder (20) is placed inside the outer casing (11) so as to surround the periphery of the separator (13) to hold the separator (13). The metal holder (20) includes a holding portion (21) which is in contact with the separator (13) to hold the separator (13), and an outer casing contact portion (23) which is in contact with an inner peripheral surface (11b) of the outer casing (11). The outer casing contact portion (23) is welded to only the outer casing (11) and fixed to the outer casing (11).