Seat Back Frame with Partial-Cutout Tube Design for Weight Reduction
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Solution Overview
Problem
Existing seat back frames for vehicles face a trade-off between strength, material cost, size, and weight, making it difficult to optimize all these factors simultaneously while maintaining structural integrity and crash resistance.
Innovation Solution
The use of 0.8mm thick rectangular tubes made of Advanced High Strength Steel (AHSS) with partial cutouts in side-member tubes allows for interlocking with smaller cross-member tubes, reducing weight and the number of welds, and direct recliner attachment without additional brackets, using a hollow single piece weld nut/inner sleeve for secure mounting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional rigid frame materials and designs are used, then strength and structural integrity are maintained, but weight increases and vehicle space decreases
Solution Approach 1:
The patent changes the material parameter from traditional steel to Advanced High Strength Steel (AHSS), which has superior strength-to-weight ratio. This allows the frame to maintain required strength while reducing weight by using thinner 0.8mm tube walls instead of thicker traditional materials.
Solution Approach 2:
The frame is segmented into different tube types (side-member tubes with partial cutouts, cross-member tubes without cutouts) with optimized dimensions for specific locations. This segmentation allows weight reduction in non-critical areas while maintaining strength where needed.
2Ease of manufacture
If traditional frame designs with full cutouts are used, then assembly ease is improved, but structural strength deteriorates
Solution Approach 1:
Instead of making full cutouts through the entire tube wall for easy assembly, the patent uses partial cutouts that extend only partway through the tube wall thickness. This partial action provides sufficient assembly ease while preserving the majority of the tube's structural strength.
3Strength
If multiple brackets and additional components are used for recliner attachment, then structural strength is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The side-member tubes are designed with multi-functionality: they provide structural support, enable easy assembly through partial cutouts, and directly accommodate recliner attachments. This universal design eliminates the need for separate brackets and additional components, reducing complexity while maintaining strength.
4Strength
If larger frame dimensions are used, then structural support is improved, but vehicle space and performance deteriorate
Solution Approach 1:
The patent uses AHSS, a composite material with enhanced properties, to achieve required structural support with smaller frame dimensions. The superior material properties allow the frame to be more compact while maintaining or improving strength compared to traditional materials.
Data Source
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AI summary
A back frame (28) for a seat back (18). The back frame (28) has side members (30) and cross members (32). The side members (30) have a dimension (40) which is larger than a corresponding dimension (42) of the crossmembers (32). The dimensions (40) and (42) being taken along the same direction. The crossmember (32) is inserted into a partial opening (34) in the side member (30). Since the dimension (42) is less than the dimension (40), the partial opening (34) does not extend across the entire dimension (42). Instead the opening (34) only partially extends across the dimension (40) to a length substantially equal to dimension (42). The partial opening (34) is arranged against one side of the side member (30), so that the cross member (32) is positioned closer to that side. Sleeve nuts (36) are arranged in the side members (30), and are used to attach a recliner (54) which then attaches to the seat base (16).