Vehicle Door Safety Beam Groove Design for Corrosion Resistance
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Solution Overview
Problem
Existing vehicle door safety beams are prone to crevice corrosion due to the design of their attachment ends, which can lead to structural vulnerabilities and corrosion issues.
Innovation Solution
The attachment end of the door beam features at least three grooves forming through channels to the underlying vertical structure, with each flat surface between the grooves having only one spot weld, and is subsequently rustproofed by immersion in an anti-corrosive paint bath.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If multiple spot welds are used on flat surfaces at the attachment end, then the attachment strength is improved, but the risk of crevice corrosion increases due to multiple crevice formations
Solution Approach 1:
The patent applies local quality by creating distinct zones with different properties: grooves (channels) in some areas to enable paint penetration and corrosion protection, and flat surfaces with spot welds in other areas to provide attachment strength. This spatial differentiation of functions resolves the contradiction between strength and corrosion resistance.
Solution Approach 2:
The patent converts the harmful effect of crevices (which normally trap moisture and cause corrosion) into a beneficial feature by designing grooves that actively channel anti-corrosive paint to the attachment end. The same crevice structures that could cause corrosion are instead used to deliver protective paint, transforming the harmful factor into a protective mechanism.
2Object-affected harmful factors
If the attachment end is designed with grooves and flat surfaces, then the risk of crevice corrosion is reduced, but the manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by forming the grooves and flat surface structures on the attachment end before the spot welding and paint immersion processes. This pre-structuring enables subsequent manufacturing steps to proceed more efficiently, as the paint channels are already in place to guide anti-corrosive paint during immersion, and the flat surfaces are positioned for optimal weld placement.
3Strength
If the flat surfaces have larger width at spot welds, then the spot weld strength is improved, but the amount of paint required increases
Solution Approach 1:
The patent applies local quality by creating localized flat surfaces with specific width dimensions (10-35 mm) only at the precise locations where spot welds are needed, rather than providing large flat surfaces across the entire attachment end. This localized approach provides sufficient weld strength while minimizing the overall surface area that would require paint coverage, thus reducing the quantity of anti-corrosive paint required.
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 design effectively reduces the risk of crevice corrosion by allowing anti-corrosive paint to fill the grooves and inhibit corrosion, enhancing the structural integrity and durability of the door beam.
Implementation Method 1
the grooves are filled with paint which then flows out as the grooves are open in both directions
Data Source
AI summary
A safety beam (11) in a vehicle door comprises an attachment end with a plurality of grooves (22, 23, 24) forming through channels to the underlying structure. The grooves have a height of 1-6 mm and an inner width of 3-7 mm and flat surfaces (18-21) between the grooves and to the outside of the outermost grooves have a width of 15-30 mm. Each of the flat surfaces comprises only one spot weld (26-29) to the underlying structure (12). The safety beam is immersed in a bath of anti-corrosive paint after assembly and is thus protected against crevice corrosion.