Vehicle Seat Back Shear Center Load Path Design
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Solution Overview
Problem
Traditional vehicle seat backs often compromise between comfort and safety during collisions due to inefficient load force transmission, and they typically require more weight and size to achieve structural integrity.
Innovation Solution
The vehicle seat back design incorporates first and second support members with a central web and rear wall, connected by a recliner heart, which directs shear center loads along an inside corner connection into the seat base, optimizing load path alignment and minimizing material usage through thin metal construction and integrated components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional vehicle seat back designs are used, then structural integrity and safety are maintained, but weight and size increase
Solution Approach 1:
The seat back is divided into multiple support members (first and second support members) with distinct functional zones. Each support member contains a shear center load path that segments the load transmission function, allowing optimized material distribution and reduced overall weight while maintaining structural integrity.
Solution Approach 2:
The support members feature non-uniform thickness distribution with thicker regions at critical load path locations (inside corner connections) and thinner regions elsewhere. This local quality variation optimizes strength where needed while minimizing material usage and weight in less critical areas.
2Reliability
If traditional vehicle seat back designs are used, then safety during collisions is ensured, but load force transmission efficiency decreases
Solution Approach 1:
The shear center load paths are designed as continuous structures extending from the top of the support members down to the seat base. This continuity ensures uninterrupted load force transmission during collisions, maximizing energy transfer efficiency and safety without gaps or weak points in the load path.
Solution Approach 2:
The design converts the potentially harmful lateral forces during collisions into beneficial compressive loads along the shear center load paths. By positioning the shear centers at inside corners and creating direct load paths to the seat base, the structure transforms collision energy into useful load transmission that strengthens rather than weakens the overall system.
3Strength
If more materials are used to achieve structural integrity, then strength and safety improve, but manufacturing cost and complexity increase
Solution Approach 1:
Multiple functions are merged into single integrated components. The support members simultaneously provide structural support, load transmission, and shear center functionality. The recliner heart integrates the seat base connection with the support members, eliminating the need for separate reinforcement structures and simplifying manufacturing.
Solution Approach 2:
The support members serve multiple purposes: they provide the primary structural framework, contain the shear center load paths for collision safety, and integrate with the recliner heart mechanism. This multi-functionality reduces the total number of components needed and simplifies the overall manufacturing process while maintaining structural integrity.
Data Source
AI summary
A vehicle seat back has first and second support members each having a central web and a rear wall extending therefrom. A seat base is operably connected with the first and second support members. A recliner heart operably connects the seat base with the first and second support members. A shear center of the first and second support members extends along an inside corner connection of the central web and the rear wall of the first and second support members and into the seat base.