Composite Liftgate Inner Panel Reinforcement Without Steel
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Solution Overview
Problem
Current liftgate systems face challenges in achieving lightweight, structurally sound designs that meet load requirements while being cost-effective, with issues such as high weight, complex manufacturing, limited styling flexibility, and inadequate reinforcement, and lack of access features for maintenance.
Innovation Solution
A composite liftgate system featuring a two-piece outer panel and an inner panel with molded structural channels and bonded composite preforms provides structural support, eliminating steel reinforcements and using adhesives for a continuous attachment, along with access doors for maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If steel liftgates are used, then structural strength is sufficient, but weight is high and manufacturing cost is high
Solution Approach 1:
The patent uses a composite structure consisting of an inner thermoplastic panel, outer panels, and foam core material. This composite construction provides sufficient structural strength while significantly reducing weight compared to traditional steel liftgates. The thermoplastic inner panel with integrated ribs and foam core creates a lightweight yet strong assembly that meets both strength and weight reduction goals.
2Strength
If steel liftgates are used, then structural strength is sufficient, but manufacturing cost and tooling cost are high
Solution Approach 1:
The composite construction using thermoplastic panels and foam core eliminates the need for expensive steel stamping tools and multi-step manufacturing processes. The thermoplastic inner panel can be molded with integrated structural ribs in a single operation, and the foam core is injected directly into the mold cavity, significantly reducing tooling costs and manufacturing complexity compared to traditional steel liftgate fabrication.
Solution Approach 2:
The patent combines multiple functions into the thermoplastic inner panel, which serves as both the structural framework (with integrated ribs) and the mounting surface for outer panels. This merging of structural and cosmetic functions into a single molded component reduces the number of parts and assembly steps, thereby lowering manufacturing cost.
3Strength
If structural reinforcements such as ribs are added onto the panel, then structural strength is improved, but manufacturing complexity increases and weight increases
Solution Approach 1:
The structural ribs are integrated directly into the thermoplastic inner panel during the molding process, rather than being added as separate components. This integration eliminates the need for additional manufacturing steps for rib fabrication and attachment, reducing manufacturing complexity while maintaining the structural strength benefits of ribbed reinforcement.
4Strength
If steel reinforcement structures are used, then structural strength is sufficient, but weight increases and manufacturing complexity increases
Solution Approach 1:
The patent replaces traditional steel reinforcement structures with a composite system consisting of the thermoplastic inner panel with integrated ribs and foam core material. This composite approach achieves the necessary structural strength without the weight and manufacturing complexity associated with steel reinforcement brackets and fasteners.
5Strength
If bolts are used for attachment structures, then structural connection is achieved, but attachment strength is insufficient due to discrete connection points
Solution Approach 1:
The patent replaces the mechanical bolt connection system with a continuous adhesive bonding system. The outer panels are bonded to the thermoplastic inner panel using adhesive applied to the foam core surface, creating a continuous attachment structure that provides superior strength compared to discrete bolt connections while simplifying the attachment structure.
Data Source
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AI summary
A composite liftgate system with an inner panel construction having a strengthening channel structure. Structural composite reinforcements are bonded to the inner panel where additional strength is needed to meet predetermined performance requirements. Where the extra structure is needed, no steel or a minimum amounts of steel is used and the structural reinforcements are bonded in place using adhesive prior to application of additional fasteners.