Multi-Layer Polyurethane Foam Seat Pad to Reduce Lateral Shakiness
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Solution Overview
Problem
Flexible polyurethane foam molded articles, such as seat pads, experience shakiness when subjected to centrifugal forces during vehicle turns or lane changes, causing the top surface layer to deviate laterally and potentially tilt the occupant or mounting object.
Innovation Solution
A flexible polyurethane foam molded article with multiple layered parts, where the front surface layer has the lowest residual thickness ratio at 15% compression and the back surface layer has the highest at 50% compression, ensuring even surface compression and reduced lateral tension.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a top surface layer and core layer are used to improve seating comfort, then the feeling of seating is improved, but the top surface layer deviates laterally under centrifugal force causing shakiness
Solution Approach 1:
The seat pad is divided into multiple layer parts (first layer part, second layer part, third layer part) with different compression characteristics. The front surface layer is segmented to have lower residual thickness ratio at 15% compression, allowing initial deflection, while back surface layers maintain higher ratios for stability during turns.
Solution Approach 2:
Different layer parts are assigned different local compression properties. The front surface layer parts have optimized residual thickness ratios specifically for lateral stability, while maintaining overall seating comfort through the gradient structure from front to back layers.
2Ease of operation
If the front surface layer compresses easily to improve comfort, then initial deflection is better, but lateral deviation increases under centrifugal force
Solution Approach 1:
The layer parts exhibit dynamic compression behavior where the front surface layer shows different residual thickness ratios at different compression levels. At 15% compression, it has the lowest ratio for comfort, but the gradient structure prevents excessive lateral deviation by distributing deformation across multiple layers.
Solution Approach 2:
The seat pad uses a composite multi-layer structure where each layer has optimized properties. The combination of layers with different residual thickness ratios creates a system that provides both initial comfort deflection and lateral stability under centrifugal loading.
3Stability of the object's composition
If multiple layer parts are used to improve lateral stability, then shakiness is reduced, but the complexity of the structure increases
Solution Approach 1:
The seat pad is segmented into three main layer parts with specific compression characteristics. This segmentation provides lateral stability through the gradient structure while keeping the overall design relatively simple and manufacturable.
Solution Approach 2:
Instead of complex structural arrangements, the invention achieves lateral stability by changing the compression parameters (residual thickness ratios) of each layer part. This parameter-based approach simplifies the design compared to mechanical stabilization mechanisms.
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 configuration reduces the feeling of shakiness while maintaining a comfortable seating experience by allowing the front layer to deflect initially and the back layer to provide stable support during increased compression.
Implementation Method 1
the core layer absorbs vibrations
Implementation Method 2
obtained by foam molding a foaming stock solution
Data Source
AI summary
A flexible polyurethane foam molded article includes a plurality of layer parts (L1 to L10) that are layered in a vertical direction (Y) perpendicular to a stage surface (1A). When the entire flexible polyurethane foam molded article is compressed by 15% in the vertical direction (Y), the front surface layer (L1) positioned closest to the stage surface (1A) in the vertical direction (Y) among the plurality of layer parts (L1 to L10) has the lowest residual thickness ratio in the vertical direction (Y) among the plurality of layer parts (L1 to L10). When the entire flexible polyurethane foam molded article is compressed by 50% in the vertical direction (Y), the back surface layer (L10) positioned closest to a non-stage surface (1B) of the flexible polyurethane foam molded article in the vertical direction (Y) among the plurality of layer parts (L1 to L10) has the highest residual thickness ratio in the vertical direction (Y) among the plurality of layer parts (L1 to L10).