Segmented Flange Bolt Fastening for Exhaust Purification Sealing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In diesel engine exhaust gas purification systems, the existing structure of multiple inner and outer cases connected via flanges is prone to stress concentration and distortion, leading to potential leaks and reduced sealing performance due to welding-induced issues.
Innovation Solution
The implementation of a support body fastened to sandwiching flanges without welding, with bolt fastening portions and divided units surrounding the outer case, enhances adhesion and rigidity while preventing deformation and leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If flange bodies are welded and fixed to outer cases, then connection strength is improved, but stress concentration and welding distortion occur causing potential leaks
Solution Approach 1:
The flange body is divided into multiple separate flange units that are arranged circumferentially around the outer case. These segmented flange units are fastened to the outer case using bolts rather than welding, distributing the connection points and reducing stress concentration at any single location while maintaining overall connection strength and sealing reliability
Solution Approach 2:
The welding connection method is replaced with a mechanical fastening system using bolts and flange units. This substitution eliminates the thermal effects of welding that cause distortion and stress concentration, while providing a reliable mechanical connection that maintains both strength and sealing integrity through distributed fastening points
2Strength
If flange bodies are welded to outer cases, then structural integrity is improved, but welding distortion deteriorates flatness of flange
Solution Approach 1:
The flange is segmented into multiple flange units positioned around the outer case, each fastened independently with bolts. This segmentation prevents the thermal distortion associated with welding entire flange structures, maintaining the flatness and manufacturing precision of each individual flange unit while preserving overall structural integrity through the distributed fastening system
Solution Approach 2:
Welding is replaced with mechanical bolt fastening, which does not introduce thermal distortion. This allows the flange units to maintain their original flatness and dimensional accuracy achieved during manufacturing, while still providing the necessary structural integrity through the mechanical connection system
3Strength
If support body is welded to sandwiching flange, then adhesion is improved, but stress concentration and distortion occur
Solution Approach 1:
The support body connection is segmented into multiple bolt fastening points distributed around the sandwiching flange. This segmentation distributes the mechanical load and stress across multiple locations rather than concentrating it at a single welded joint, reducing stress concentration while maintaining strong adhesion through the distributed mechanical fastening system
Solution Approach 2:
The welding connection between the support body and sandwiching flange is replaced with mechanical bolt fastening. This substitution eliminates the localized heat input and stress concentration inherent in welding, while providing equivalent or superior adhesion through the distributed mechanical connection points that allow for stress distribution
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Inner cases (4, 20, 31) are connected to outer cases (5, 21, 32) through joining flanges (25, 26, 40, 41) which protrude toward outer peripheries of the outer cases (5, 21, 32). A plurality of combinations each including filters (2, 3), the inner cases (4, 20, 31), and the outer cases (5, 21, 32) are provided. Both the joining flanges (25, 26) (40, 41) are sandwiched and fixed between a pair of sandwiching flanges (51, 52) (53, 54), thereby connecting the plurality of outer cases (5, 21, 32) to each other.