Vehicle Seat Frame Layout for Side-Frame Rigidity and Weld Access
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Solution Overview
Problem
Existing vehicle seat frames face challenges in achieving sufficient rigidity to prevent inward bending of side frames, particularly when connected by a connection frame, while also avoiding interference with surrounding members and promoting efficient welding operations.
Innovation Solution
The seat frame design includes side frames with a connection frame that features first and second extension portions, where the second extension portions overlap with the side walls and extend in an arc shape to enhance rigidity, avoiding areas with reclining mechanism attachments and swing shafts, and are welded in a manner that secures strength without interfering with the reclining mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the connection frame is attached to the side frames by welding, then the rigidity of the side frames is increased, but the welding operation becomes more difficult due to restricted access at the attachment locations
Solution Approach 1:
Instead of welding the connection frame to the side frames from the conventional approach, the patent inverts the welding approach by performing welding from the rear surface side of the side frames toward the front, allowing the welding torch to access the welding position from behind the seat cushion assembly, thereby improving welding accessibility while maintaining joint strength
2Strength
If the connection frame is designed to maximize rigidity, then the inward bending of side frames is suppressed, but the connection frame interferes with surrounding members such as the reclining mechanism and swing shafts
Solution Approach 1:
The connection frame is segmented into multiple components: a main body portion and separate reinforcement portions. The reinforcement portions are strategically positioned to provide rigidity only where needed for suppressing inward bending, while the segmented structure allows clearance for the reclining mechanism and swing shafts in other areas, thus resolving the conflict between strength and adaptability
Solution Approach 2:
The connection frame employs local quality by concentrating reinforcement only in specific areas where rigidity is critical for preventing inward bending of side frames, rather than uniformly thickening the entire connection frame. This localized reinforcement approach maintains necessary strength while preserving clearance for surrounding moving components
3Productivity
If the number of components in the seat frame is reduced, then the number of welding operations decreases improving workability, but the rigidity of the side frames becomes insufficient
Solution Approach 1:
The connection frame is merged with reinforcement portions that are integrally formed as a single piece, combining the functions of connection and reinforcement into one component. This merging reduces the total number of parts and welding operations needed, while the integrated reinforcement portions ensure sufficient rigidity is achieved without requiring additional separate reinforcement components
Data Source
AI summary
A seat frame for a vehicle seat has side frames disposed on both ends of a seat back frame in the width direction, and a bottom member frame for connecting the bottom ends of the side frames which attach to a seat cushion, wherein: each side frame has a side wall which is positioned on the outside in the width direction and which extends in the vertical direction, and a back wall which extends from the side wall towards the inner side in the width direction; and the lower member frame has a first extension portion extending along the width direction, and second extension portions extending from both ends of the first extension portion in the width direction towards the front. The second extension portions are positioned further inward than the side walls in the width direction and overlap with the side walls.