Closed-Cell EVA Seat Components With Integral Trim and Attachment
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Solution Overview
Problem
Current vehicle interior trim and seating solutions lack integration of foam and plastic features, failing to fully utilize the unique characteristics of EVA materials for simplified processes, reduced assembly times, improved craftsmanship, and enhanced durability and cleanliness.
Innovation Solution
A vehicle seat assembly utilizing a closed-cell foam shell that covers the backrest, seat cushion, and headrest, with integral attachment features for component mating, formed from EVA material, which self-skins and integrates with the frame-like structure for aesthetic and functional benefits, including reduced labor costs and antimicrobial surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional foam and trim components are used separately in vehicle interiors, then manufacturing flexibility is maintained, but assembly complexity and labor costs increase
Solution Approach 1:
The patent combines foam and trim components into a single integrated EVA molded part. The foam core and exterior trim surface are formed as one unified component through injection molding, eliminating the need for separate assembly operations and reducing labor costs while maintaining manufacturing flexibility through mold design variations.
Solution Approach 2:
The EVA material serves multiple functions simultaneously: it provides the structural foam core, the exterior trim surface, attachment features, and aesthetic finishing all in one material. This multi-functionality reduces the number of separate components needed and simplifies the overall assembly process.
2Adaptability or versatility
If multiple separate components are assembled for vehicle interior trim, then design flexibility is maintained, but assembly time increases
Solution Approach 1:
The foam core and exterior trim are merged into a single molded component, eliminating assembly time between these parts. The integral construction allows the part to be installed as one unit while still providing design flexibility through mold cavity configurations and material properties.
3Ease of operation
If traditional foam components are used, then comfort is provided, but durability and cleanability are reduced
Solution Approach 1:
The patent uses EVA (ethylene-vinyl acetate copolymer) as a composite material that combines the cushioning properties of foam with the durability and cleanability of plastic. The material integrates the soft, comfortable characteristics of foam with the stain-resistant and easy-to-clean properties of thermoplastic materials.
Solution Approach 2:
The entire component is made from a homogeneous EVA material throughout, eliminating the interface between different materials (foam and trim) that would otherwise create vulnerability points. This homogeneity provides consistent durability and cleanability across the entire surface while maintaining comfort properties.
4Productivity
If EVA foam is used for vehicle interior components, then assembly time is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent utilizes the temperature-dependent properties of EVA material during molding and assembly. The material's viscosity and dimensional stability change with temperature, allowing for precise molding at elevated temperatures and subsequent contraction during cooling to achieve tight fits and precise dimensional tolerances.
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 provides a durable, aesthetically appealing, and easy-to-clean vehicle interior with reduced assembly times and labor costs, leveraging the self-skinning properties of EVA foam to create a single-material finished part with molded-in attachment features and customizable designs.
Implementation Method 1
EVA polymers become cross-linked during the molding process, or separate cooking process, which results in a very stable part. Due to the properties of EVA materials, it is typical for the molded part to rapidly expand upon mold separation
Implementation Method 2
As the molded part cools, it shrinks and typically returns to an as-molded (or scaled design) size
Implementation Method 3
Prior to cooling, a wheel hub rim is inserted inside the annular tire and held there until the molded EVA portion cools and shrinks to a snug fit over the hub. In this manner, the EVA tire becomes permanently installed by way of mechanical lock, having hot shrunk into its final assembled condition on the hub
Data Source
AI summary
A vehicle seat assembly including at least a component of the seat assembled made of closed-cell foam and having an integral exterior surface. The component may include a backrest, headrest, seat cushion or a component thereof such as an armrest. A method of forming a seat assembly including a first seat component and a second seat component wherein at least one of the first and the second components are made of closed-cell foam.