Seat Core Material with Slits to Reduce Frame-Induced Deformation
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Solution Overview
Problem
The existing seat core materials for automobile seats face issues with deformation and lack of dimension accuracy due to the differing shrinkage ratios of expanded bead articles and embedded frame members, leading to instability and poor attachment accuracy.
Innovation Solution
A seat core material design featuring a thermoplastic resin expanded bead article with strategically placed slits and an auxiliary slit, integrated with an annular frame member, which allows for independent shrinkage of the bead article while maintaining structural unity and strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the expanded bead article is completely divided into multiple parts, then each part can shrink independently to improve dimension accuracy, but the seat core material lacks overall unity and may become bent or deformed during handling
Solution Approach 1:
The expanded bead article is divided into multiple shrunk parts through slits, allowing independent shrinkage of each segment to improve dimension accuracy while maintaining overall structural integrity
Solution Approach 2:
The slit depth is varied locally - shallower in some areas and deeper in others - to control the degree of separation and shrinkage independence in different regions, balancing dimension accuracy with structural unity
2Manufacturing precision
If the expanded bead article is completely divided, then independent shrinkage is achieved, but the seat core material may become bent or deformed at the time of handling
Solution Approach 1:
The expanded bead article is segmented into multiple parts through slits to enable independent shrinkage, improving dimension accuracy while maintaining sufficient handling strength through controlled segmentation
Solution Approach 2:
The slit depth is controlled to be shallower in regions requiring handling strength, allowing the material to remain sufficiently connected to resist bending and deformation during handling
3Reliability
If the frame member is embedded in the expanded bead article, then attachment to vehicle body and collision reinforcement are improved, but the frame member becomes deformed due to shrinkage of the expanded bead article causing warp in the seat core material
Solution Approach 1:
The expanded bead article is segmented into multiple shrunk parts that can shrink independently, reducing the shrinkage force transmitted to the embedded frame member and preventing deformation and warping
Solution Approach 2:
The slit depth is optimized locally to control the balance between allowing sufficient shrinkage for dimension accuracy and limiting shrinkage force transmission to protect the embedded frame member from deformation
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 achieves excellent dimension accuracy and stability, reducing deformation and enhancing the sense of unity and strength of the seat core material, even when the frame member is embedded and integrated with the expanded bead article.
Implementation Method 1
The expanded bead article generally shrinks after in-mold molding, and thus the shape of the expanded bead article becomes stable with smaller dimensions than the metal mold dimensions
Data Source
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Figure 3(A)~3(C)
AI summary
A seat core material of the present invention is a seat core material for vehicle including: a thermoplastic resin expanded bead article; and a frame member embedded in a peripheral edge portion of the expanded bead article. The expanded bead article has two or more lightening parts in an area from a center portion as seen in a front-back direction to a rear side. A through or non-through slit is provided in a continuous part between the lightening parts or an area in front of the continuous part over a distance of 100 mm or less along a vehicle-width direction of the expanded bead article. The slit is closed at both longitudinal ends. It is possible to provide a seat core material with a sense of unity and a sufficient strength in which an expanded bead article becomes less deformed and the expanded bead article is very excellent in dimension accuracy even when a frame member is embedded in the expanded bead article and the expanded bead article and the frame member are integrated with each other.