Vehicle Armrest Frame with Variable Wall Thickness
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Solution Overview
Problem
Existing motor vehicle armrests lack effective collapsibility upon impact while maintaining the ability to support vertical loads from occupants, which is a critical safety and design requirement.
Innovation Solution
A vehicle armrest design featuring a unitary frame with a thinner pliable body and a thicker stiffer perimeter, combined with vertical portions that abut the doorframe, defines a cavity for a cushion and is covered with a layer, enhancing collapsibility and structural support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the armrest is designed with a thicker uniform structure, then it can support vertical loads, but it cannot collapse laterally upon impact
Solution Approach 1:
The armrest frame incorporates varying wall thicknesses within a single structure: thicker sections (e.g., at corners and connection points) provide strength for vertical load support, while thinner sections enable lateral collapsibility upon impact. This local variation in structural properties allows simultaneous achievement of both load-bearing capacity and impact energy absorption.
Solution Approach 2:
The armrest frame is designed as a unitary structure with segmented thickness distribution, creating distinct functional zones: rigid perimeter sections for structural integrity and pliable body sections for controlled collapse. This segmentation of structural properties within a single piece enables differentiated mechanical responses to different types of loads.
2Object-affected harmful factors
If the armrest is designed to be collapsible upon impact, then it improves safety, but it cannot support vertical loads from occupants
Solution Approach 1:
The frame structure features strategically placed thick and thin sections: thicker perimeter regions maintain rigidity for vertical load support while thinner body sections provide controlled collapsibility for impact safety. This local differentiation resolves the contradiction between strength and collapsibility.
Solution Approach 2:
The wall thickness parameter is varied throughout the frame structure to create regions with different mechanical properties. Thicker regions exhibit higher stiffness and strength for load support, while thinner regions exhibit lower stiffness enabling controlled collapse during impact, thus changing the structural parameter (thickness) to achieve multiple functions.
3Adaptability or versatility
If the armrest uses a unitary frame with varying thickness, then it achieves both collapsibility and load support, but manufacturing complexity increases
Solution Approach 1:
The armrest integrates multiple functions (vertical load support, lateral collapsibility, cushion retention, aesthetic cover) into a single unitary frame structure. This merging of functions into one molded piece eliminates the need for separate components and assembly steps, actually simplifying manufacturing despite the varying thickness requirements.
Solution Approach 2:
The molding process utilizes parameter changes in wall thickness as a standard design variable, allowing the creation of a unitary structure with differentiated mechanical properties. Modern injection molding technology can efficiently produce such variable-thickness structures in a single operation, making the manufacturing complexity manageable.
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 design improves lateral collapsibility upon impact while maintaining the ability to support vertical loads, ensuring both safety and comfort for vehicle occupants.
Implementation Method 1
a unitary frame defining a horizontal portion having a thinner pliable body... The design improves lateral collapsibility upon impact
Implementation Method 2
a thinner pliable body and a thicker stiffer perimeter surrounding the body... maintaining the ability to support vertical loads
Data Source
AI summary
A vehicle armrest includes a unitary frame defining a horizontal portion having a thinner pliable body and a thicker stiffer perimeter surrounding the body, and first and second vertical portions extending in opposite directions from ends of the horizontal portion. The first vertical portion abuts an inner doorframe, and the horizontal and first vertical portions define a cavity configured to retain a cushion over the body. The vehicle armrest further includes a cover layer over the cushion and frame.