Vehicle Seat Frame with Gradual Section Transition
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Solution Overview
Problem
Vehicle seat frames with closed sectional shapes and reduction holes face stress concentration issues due to rapid changes in section modulus, compromising the balance between structure strength and weight.
Innovation Solution
A vehicle seat design incorporating a closed section frame and an opened section frame with a closure forming part and a gradually changing structure, where the opened section frame is coupled with the closed section frame to form a closed sectional shape, effectively modifying the section modulus and reducing stress concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If reduction holes are formed in the closed section frame to reduce weight, then weight is reduced, but stress concentration occurs due to rapid changes in section modulus
Solution Approach 1:
The seat frame is divided into multiple sections: closed section frames in high-stress areas and opened section frames in low-stress areas. This segmentation allows each part to be optimized for its specific function - the closed sections provide strength where needed while the opened sections reduce weight where less strength is required, avoiding stress concentration at transitions.
Solution Approach 2:
Different sectional shapes are applied to different parts of the seat frame based on local stress requirements. Closed sectional shapes are used in areas requiring high strength and rigidity, while opened sectional shapes are used in areas where weight reduction is prioritized. This local differentiation optimizes the overall structure without causing stress concentration.
2Weight of moving object
If the section modulus is rapidly changed to optimize weight, then weight is reduced, but stress concentration occurs
Solution Approach 1:
The transition between closed and opened section frames incorporates curved or gradually changing geometries rather than abrupt changes. This gradual transition smooths the distribution of section modulus along the frame length, preventing stress concentration while still achieving weight reduction through the opened sections.
3Strength
If a closed sectional shape is used throughout the seat frame, then structure strength is improved, but weight increases
Solution Approach 1:
Instead of uniformly applying closed sectional shapes throughout the entire seat frame, the invention applies closed sections only in areas requiring high strength (such as areas subjected to large loads or bending moments) while using opened sections in areas where weight reduction is more critical. This localized approach optimizes the strength-to-weight ratio.
Solution Approach 2:
The seat frame is segmented into multiple sections with different sectional shapes based on the structural requirements of each segment. This allows the frame to achieve adequate overall strength while reducing weight by using opened sections in appropriate locations.
Data Source
AI summary
A vehicle seat includes: a seat frame that is provided as a strength member and extends in a specific direction, the seat frame including: a closed section frame having a closed sectional shape and extending in the specific direction, an opened section frame having an opened sectional shape and extending in the specific direction in parallel with the closed section frame, wherein the opened section frame is coupled with the closed section in a state to have a closure forming part and a gradually changing structure, wherein the closure forming part forms a closed sectional shape between the opened section frame and the closed section frame, and wherein the gradually changing structure changes the closed sectional shape formed between the opened section frame and the closed section frame at the closure forming part.