Inclined Surface Welding for Gas Sensor Protrusion Control
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Solution Overview
Problem
When coaxially resistance-welding two cylindrical bodies, protruding portions often form on the outer radial side of the welded body due to melted metal, which can prevent the welded body from being inserted into other members and necessitate additional operations for removal.
Innovation Solution
The method involves preparing cylindrical bodies with inclined end surfaces that angle towards the center axis, such that the distance between the end surfaces increases towards the center axis, with an angle of 5° to 15°, to direct melted metal flow inwardly during welding, thereby suppressing protrusion formation on the radial outer side while maintaining sufficient joint strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If coaxial resistance welding is performed on two cylindrical bodies with flat end surfaces, then the welding process is simple and fast, but protruding portions form on the radial outer side due to melted metal
Solution Approach 1:
The end surfaces of the cylindrical bodies are designed with inclined surfaces instead of flat surfaces. The inclination angle is specifically set to 5° to 15° to control the flow direction of melted metal during welding, preventing protruding portions while maintaining welding efficiency
Solution Approach 2:
The inclined surfaces create an asymmetric geometry at the welding interface. This asymmetry directs the melted metal flow toward the center axis rather than allowing it to protrude radially outward, solving the protrusion problem while keeping the process simple
2Manufacturing precision
If the inclination angle of end surfaces is increased to suppress protruding portions, then protrusion formation is reduced, but joint strength decreases
Solution Approach 1:
The inclination angle is optimized to a specific range of 5° to 15°. This parameter optimization balances two competing requirements: angles within this range effectively direct melted metal inward to prevent protrusions, while simultaneously maintaining sufficient contact area and pressure distribution to ensure adequate joint strength
3Manufacturing precision
If additional operations are performed to remove protruding portions, then surface quality is improved, but production time and complexity increase
Solution Approach 1:
The inclined surfaces are prepared in advance on the cylindrical bodies before welding. This preliminary geometric configuration prevents protruding portions from forming during the welding process itself, eliminating the need for subsequent removal operations and maintaining high production efficiency
Solution Approach 2:
The inclined surfaces convert the potentially harmful effect of melted metal flow into a beneficial outcome. By directing the melted metal flow toward the center axis through the inclined geometry, the natural flow of molten material is harnessed to prevent protrusions rather than fight against it
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 approach effectively prevents the formation of protruding portions on the radial outer side of the welded body, ensuring it can be properly integrated into other components without additional removal steps, while maintaining adequate joint strength.
Implementation Method 1
resistance-welding the first end surface and the second end surface to produce the welded body by energizing a contact portion between the first cylindrical body and the second cylindrical body
Implementation Method 2
melted metal more easily flows toward the center axis than toward the radial outer side of the first and second cylindrical bodies
Data Source
AI summary
In a main metal piece 60 and an inner cylinder 70 serving as cylindrical bodies before welding, a second end surface 75 is an inclined surface that inclines toward an end portion opposite from the second end surface 75 as the second end surface 75 extends toward the center axis, and an angle θ2a is 5° to 15°. Thus, the distance between a first end surface 65 and the second end surface 75 positioned in resistance welding increases toward the center axis, and an angle θc (=angle θ2a) between the first end surface 65 and the second end surface 75 is 5° to 15°.