Vacuum insulated structure with sheet metal features to control vacuum bow
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Solution Overview
Problem
Vacuum insulated structures for refrigerators face challenges in maintaining a planar configuration after vacuum evacuation, leading to deformation issues that affect insulation efficiency and aesthetic quality.
Innovation Solution
A vacuum insulated structure design featuring first and second cover members with an outer frame portion that deforms axially inward upon vacuum application, maintaining a controlled deformation to preserve insulation performance and appearance, utilizing a thermal bridge to create a sealed insulating cavity and incorporating a grid pattern of ribs for structural support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a vacuum is drawn from the insulating cavity, then insulation efficiency is improved, but the cover member deforms and loses its planar configuration
Solution Approach 1:
The cover member is divided into three distinct regions: a perimeter portion, an outer frame portion, and an inner area. This segmentation allows each region to have different structural properties - the outer frame portion is designed to deform while the inner area maintains its planar configuration, thus preserving both insulation efficiency and aesthetic appearance.
Solution Approach 2:
The outer frame portion is pre-formed with a specific geometry that includes a first planar level and a second planar level spaced apart in the axial direction. This preliminary structural configuration enables the frame to deform in a controlled manner when vacuum is applied, accommodating the insulation efficiency improvement while preventing unwanted deformation of the inner area.
2Shape
If the cover member is made rigid to maintain shape, then aesthetic quality is improved, but deformation control during vacuum evacuation becomes difficult
Solution Approach 1:
Different portions of the cover member are assigned different structural qualities. The outer frame portion is designed with geometry that allows deformation, while the inner area is configured to maintain rigidity and planar configuration. This local differentiation enables the structure to adapt to vacuum conditions while preserving aesthetic quality in the visible inner area.
Solution Approach 2:
The cover member is designed to transition from a static rigid structure to a dynamic structure that can deform in response to vacuum pressure. The outer frame portion's multi-level geometry allows it to flex and adjust during vacuum evacuation, transforming the cover member from a purely rigid component to one with controlled dynamic deformation capabilities.
3Force
If the outer frame portion deforms axially inward, then vacuum force is accommodated, but visible deformation may affect appearance
Solution Approach 1:
By segmenting the cover member into perimeter portion, outer frame portion, and inner area, the design directs vacuum-induced deformation to occur specifically in the outer frame portion. The inner area, which is visible and affects appearance, is structurally protected from deformation, thus accommodating vacuum force while minimizing visible deformation effects.
Solution Approach 2:
The outer frame portion is pre-configured with a multi-level geometry (first planar level and second planar level spaced apart axially) that anticipates and accommodates vacuum-induced deformation. This preliminary structural arrangement allows the frame to move axially inward in a controlled manner, absorbing vacuum forces before they can affect the visible inner area.
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 effectively manages deformation within the outer frame portion, maintaining insulation efficiency and aesthetic quality by allowing controlled inward movement of the inner area, ensuring minimal visible deformation and optimal performance post-vacuum draw.
Implementation Method 1
The insulating cavity is a sealed cavity having a vacuum drawn therefrom
Implementation Method 2
under a force of the vacuum within the insulating cavity
Data Source
AI summary
A vacuum insulated structure includes a first cover member of a unitary sheet member defining a perimeter portion, an outer frame portion defined radially inward of the perimeter portion, and an inner area surrounded and supported by the outer frame portion. The inner area defines a first planar level with a portion of the outer frame portion extending to a second planar level parallel to and spaced apart from the first planar level in an axial direction. The vacuum insulated structure further includes a second cover member of a unitary sheet and a thermal bridge interconnecting the first cover member and the second cover member at the perimeter portions thereof to define an insulating cavity therebetween. The outer frame portion deforms such that the inner area moves axially inward away from the second planar level under a force of the vacuum within the insulating cavity.