Overmolded Liftgate Hinge Point With Integrated Compression Limiter
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Solution Overview
Problem
Existing liftgate manufacturing methods face challenges in reducing weight and cost while providing robust hinge mounting points, as traditional cast aluminum solutions are heavy and costly, and steel reinforcements overmolded with thermoplastics struggle to effectively connect 3D metal ribs to base plates without welding, and accommodate load transfer and compression limiters.
Innovation Solution
An overmolded hinge point is created by combining a metal reinforcement with a polymer, featuring a compression limiter portion with a tubular structure for fastener reception and extending gusset ribs, allowing for secure attachment and load transfer without welding, using the overmolding process to integrate these features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If cast aluminum members are used to form the entire periphery of the liftgate, then strong and robust attachment points are provided, but the assembly becomes heavier and more costly to manufacture and assemble
Solution Approach 1:
The patent uses a composite structure combining a metal base plate with thermoplastic material overmolded onto it. This composite approach provides the strength of metal at critical attachment points while using the lighter thermoplastic material for the surrounding structure, achieving a balance between strength and weight reduction
Solution Approach 2:
The invention applies different material properties to different locations: the metal base plate provides localized strength at hinge mounting points and hard points, while the thermoplastic overmold provides lightweight structural support in non-critical areas. This localized application of material properties optimizes the strength-to-weight ratio
2Weight of moving object
If steel reinforcements overmolded with thermoplastic are used, then cost and weight are reduced, but providing reinforcements for hinge points and hard points becomes challenging and may require after overmolding assemblies to be added
Solution Approach 1:
The patent incorporates hinge mounting arrangements and hard points directly into the metal base plate before the overmolding process. This preliminary integration ensures that reinforcement features are built-in from the start, eliminating the need for post-overmolding assembly modifications or additions
Solution Approach 2:
The invention merges the metal base plate with pre-formed reinforcement features and the thermoplastic overmold into a single integrated assembly. The hinge mounting arrangements and hard points are combined with the base plate structure, allowing the entire assembly to be manufactured as one unit rather than requiring separate attachment steps
3Force
If 3D metal ribs are connected to the metal base plate to transfer load, then load transfer capability is achieved, but the manufacturing process becomes more complex requiring additional connection steps
Solution Approach 1:
The patent combines the metal ribs and metal base plate into a single integrated metal assembly before overmolding. This merging of components allows load transfer features to be built-in during the metal forming process, eliminating the need for separate connection steps or additional manufacturing operations
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 approach reduces weight and manufacturing costs by providing a strong, lightweight liftgate with secure hinge points and load transfer capabilities, eliminating the need for welding and enhancing rigidity through integrated polymer and metal reinforcement.
Implementation Method 1
a metal reinforcement overmolded with a polymer and having a compression limiter portion molded in
Data Source
AI summary
A liftgate having an overmolded hinge point comprising a metal reinforcement overmolded with a polymer and having a compression limiter portion molded in. The compression limiter portion including a tubular portion for receiving a fastener encapsulated during overmolding and having overmolded gusset ribs extending therefrom during the overmolding process.