Liftgate Standoff Structure Resists Panel Deformation
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Solution Overview
Problem
Existing liftgate latch mechanisms are prone to becoming unlatched during collisions due to severe deformation of the outer panel, which impinges on the latch or operating rod, leading to operational failures.
Innovation Solution
A liftgate assembly with a trussform inner panel and an outer panel, featuring a standoff structure between them to resist deformation and maintain latch cavity integrity, using solid polypropylene blocks slidably engaged with the outer panel and fastened to the inner panel to prevent translational movement and crushing of the latch cavity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If large-scale reinforcements are added to provide beam strength to automotive body closure panels, then structural strength is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent applies local quality by positioning specific reinforcement elements (standoff structures and internal ribs) only in critical areas around the latch cavity rather than reinforcing the entire panel. This localized approach provides necessary beam strength where impacts most affect latch operation while avoiding unnecessary complexity in other regions.
Solution Approach 2:
The reinforcement system is segmented into distinct functional components: standoff structures that maintain cavity dimensions, internal ribs that provide beam strength, and latch cavity protection elements. This segmentation allows each component to address specific structural needs independently, reducing overall device complexity compared to a monolithic reinforcement approach.
2Strength
If large-scale reinforcements are added to provide beam strength to automotive body closure panels, then structural strength is improved, but manufacturing cost increases
Solution Approach 1:
By concentrating reinforcement only where structurally necessary (around the latch cavity and hinge mounting areas), the patent reduces the total amount of material and manufacturing operations required compared to full-panel reinforcement, thereby lowering manufacturing cost while maintaining adequate beam strength.
Solution Approach 2:
The patent employs cost-effective reinforcement elements such as plastic standoff structures and integrated ribs that can be molded as part of the panel assembly, avoiding expensive metal reinforcements or complex multi-step manufacturing processes.
3Strength
If large-scale reinforcements are added to provide beam strength to automotive body closure panels, then structural strength is improved, but weight gain occurs
Solution Approach 1:
The patent provides beam strength only in critical regions through localized reinforcements rather than uniformly strengthening the entire panel. This reduces the total material mass required while maintaining adequate structural strength for latch protection during impacts.
Solution Approach 2:
The patent utilizes composite construction with plastic panels incorporating integrated rib structures and standoff elements, combining the advantages of lightweight plastic material with reinforced structural features to achieve adequate beam strength without excessive weight gain.
4Loss of energy
If the outer panel deforms severely during collision, then impact energy is absorbed, but the latch becomes unlatched due to impingement on the latch or operating rod
Solution Approach 1:
The patent applies preliminary anti-action by pre-positioning standoff structures and protective shields around the latch cavity before impact occurs. These elements are designed to counteract the deforming forces during collision, maintaining cavity dimensions and preventing the outer panel from impinging on the latch mechanism, thereby preserving latch retention despite impact energy absorption.
Solution Approach 2:
The patent introduces intermediary protective elements (standoff structures and shields) between the deforming outer panel and the latch mechanism. These intermediaries absorb and redirect impact forces, allowing the outer panel to deform for energy absorption while preventing direct impingement on the latch that would cause unlatching.
Data Source
AI summary
A liftgate assembly for an automotive vehicle includes an outer panel having an external periphery and a skeletonized, trussform inner panel joined to the outer panel at their mutual external peripheries. A latch assembly is mounted within a latch cavity defined by a section of the trussform inner panel and a facing portion of the outer panel. At least one standoff structure is interposed between the outer panel and the inner panel at a location adjacent to the latch cavity so as to resist deformation of the outer panel and consequent reduction in size of the latch cavity in the event that an impact is imposed upon the outer panel at a location near the latch cavity.