Expanded Polypropylene Impact Module for Vehicle Interiors
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Solution Overview
Problem
Plastic vehicle-interior-parts face challenges in preventing excessive deflection during dynamic seat belt tests, as existing impact modules are inadequate in maintaining structural integrity and attachment methods are not robust enough to ensure consistent performance.
Innovation Solution
A plastic vehicle-interior-part with an impact module made from expanded polypropylene foam, featuring a 3D shape with varying thickness and T-shaped slots for form- and/or force-fitting attachment, utilizing plastic barbs for secure bonding to the vehicle-part, enhancing surface quality with a coating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If existing impact modules are used in plastic vehicle-interior-parts, then the parts can provide some structural support, but they fail to prevent excessive deflection during dynamic seat belt tests
Solution Approach 1:
The patent changes the material parameters by using expanded foam material with specific density and elasticity characteristics. The foam material's cellular structure provides both strength and energy absorption capability, enabling the impact module to maintain structural integrity while controlling deflection during dynamic tests. The expansion ratio and material composition are optimized to achieve the required performance balance.
Solution Approach 2:
The patent employs composite construction by combining the expanded foam material with a plastic coating layer. The foam core provides structural support and energy absorption, while the plastic coating enhances surface quality and provides a bonding interface for attachment methods. This composite structure achieves both structural integrity and reliable deflection control.
2Ease of manufacture
If traditional attachment methods are used for impact modules, then assembly is simple, but the attachment is not robust enough to ensure consistent performance
Solution Approach 1:
The patent applies local quality enhancement by adding a plastic coating specifically to the attachment regions of the impact module. This coating creates a bonding interface that significantly improves attachment robustness while leaving the bulk foam material intact for its primary structural function. The localized treatment achieves reliable attachment without complicating the overall manufacturing process.
3Ease of manufacture
If the impact module uses a uniform thickness design, then manufacturing is easier, but it cannot optimally adapt to the varying structural requirements of different vehicle-part regions
Solution Approach 1:
The patent implements variable thickness design where the expanded foam material is denser and thicker in high-impact regions and gradually transitions to thinner sections in lower-stress areas. This gradient structure optimizes structural adaptation to different vehicle-part regions while maintaining manufacturability through controlled foam expansion processes. The local density variations provide tailored structural support where needed.
Solution Approach 2:
The patent transitions from a uniform 2D thickness design to a 3D variable thickness configuration. The impact module incorporates depth variations and curvature that allow it to conform to the complex geometry of vehicle interior parts. This dimensional complexity enables optimal structural adaptation without significantly increasing manufacturing difficulty.
4Ease of manufacture
If the impact module surface is left uncoated, then manufacturing cost is lower, but the surface quality grade is insufficient
Solution Approach 1:
The patent applies a plastic coating layer to the surface of the expanded foam material to enhance surface quality. The coating provides a smooth, uniform finish that meets aesthetic requirements for vehicle interior applications. The coating process is integrated into the manufacturing workflow, minimizing additional cost while significantly improving surface appearance and quality grade.
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 limits deflection to less than 10 mm during dynamic seat belt tests by providing a robust and adaptable impact module that securely attaches to the vehicle-part, ensuring structural integrity and improved surface quality.
Implementation Method 1
the impact module is made from an expanded, plastic foam material... The impact module's functionality is, for example, to prevent the side valance from deflecting more than 10 mm when subjected to a dynamic seat belt test
Data Source
AI summary
The present invention relates to a plastic vehicle-interior-part with an impact module.