Windshield Differential Cooling for Localized Impact Protection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for producing composite windshields with improved impact protection are costly and increase the weight of the windshield, failing to meet safety requirements while maintaining cost-effectiveness.
Innovation Solution
A method involving the simultaneous or individual bending of outer and inner panes, followed by differential cooling rates to create varying surface compressive stresses, utilizing a thermoplastic intermediate layer to enhance impact resistance and absorb energy upon breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the materials and layer thicknesses of the composite pane are adjusted to prevent breakage, then impact protection is improved, but production costs and weight increase
Solution Approach 1:
The patent applies differential cooling rates to different regions of the glass pane: a first cooling rate in the lower region (near engine edge) and a second cooling rate in the upper region (near roof edge). This creates region-specific compressive stress distributions that optimize impact protection locally without requiring increased weight throughout the entire windshield.
Solution Approach 2:
The patent changes the cooling rate parameter during production to control the compressive stress distribution in the glass. By adjusting cooling rates in different regions, the patent optimizes impact protection characteristics without changing material composition or increasing overall thickness, thereby avoiding weight increase.
2Reliability
If the materials and layer thicknesses of the composite pane are adjusted to prevent breakage, then impact protection is improved, but production costs increase
Solution Approach 1:
The patent utilizes process parameter changes (cooling rates) rather than material changes to achieve improved impact protection. This approach avoids the need for expensive specialized materials or additional production steps, maintaining cost-effectiveness while achieving the desired safety improvement.
3Weight of moving object
If thinner glass is used to reduce weight, then fuel and electricity savings are achieved, but mechanical requirements and safety standards become harder to meet
Solution Approach 1:
The patent uses controlled cooling rate parameters to induce compressive stresses in the glass that enhance its mechanical strength and impact resistance. This allows thinner glass to meet safety requirements by optimizing the stress distribution through thermal processing rather than increasing thickness.
Solution Approach 2:
The patent applies compressive stresses to the glass during the manufacturing process (before installation) through differential cooling. This preliminary strengthening action ensures that the thinner glass meets mechanical requirements and safety standards before it is put into service.
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 method achieves improved impact protection by delaying breakage in critical regions, reducing the risk of severe head injuries in accidents, while maintaining production efficiency and avoiding additional material use.
Implementation Method 1
The glass panes are heated to their bending temperature, so that they become plastically deformable
Implementation Method 2
The pane is then heated to at least its softening temperature so that it adheres to the support surface under the influence of gravity
Implementation Method 3
the outer pane and/or the inner pane are cooled in the first surface region at a first cooling rate and the outer pane and/or the inner pane are cooled in the second surface region at a second cooling rate
Implementation Method 4
a considerable amount of energy is absorbed due to the expansion of the thermoplastic intermediate layer and the at least partial delamination in the region of the broken glass panes
Data Source
AI summary
A method for producing a windshield, includes (a) providing an outer pane and an inner pane, (b) heating the outer pane and the inner pane to at least their softening temperature, (c) jointly bending the outer pane and the inner pane or individually bending the outer pane and the inner pane, (d) cooling the outer pane and the inner pane, and (d) laminating the outer pane and the inner pane with the interposition of a thermoplastic intermediate layer to form a composite pane, wherein in procedure d) the outer pane and/or the inner pane are/is cooled in the first surface region at a first cooling rate and the outer pane and/or the inner pane are/is cooled in the second surface region at a second cooling rate, and the absolute value of the first cooling rate is greater than the absolute value of the second cooling rate.