Vehicle Seat Torsion Spring Preload Adjustment
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Solution Overview
Problem
Vehicle seat assemblies face challenges in efficiently biasing the seat back to a folded position due to variations in trim packages and assembly tolerances, which can result in friction issues preventing smooth folding.
Innovation Solution
A vehicle seat assembly with a torsion spring mechanism and a series of blocks with varying thicknesses to provide adjustable preload, allowing the seat back to rotate from a use position to a folded position with reduced user input, utilizing a support stud and a biasing mechanism that includes a block contacting the torsion spring to bias the seat back when in the first position and unloading when in the second position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a torsion spring mechanism is used to bias the seat back to a folded position, then the seat back can be folded forward with reduced user input, but variations in trim packages and assembly tolerances can cause friction issues that prevent smooth folding
Solution Approach 1:
The patent applies parameter changes by providing a series of blocks with different thicknesses (varying parameters) to adjust the preload on the torsion spring. This allows the system to be tuned for different trim packages and assembly tolerances, ensuring smooth folding operation across various configurations. The block thickness parameter is specifically changed to match different vehicle trim levels and assembly variations.
Solution Approach 2:
The patent implements dynamics by making the preload mechanism adjustable rather than fixed. The selectable blocks allow the system to adapt its mechanical properties based on the specific configuration needed, transforming a static spring mechanism into a dynamically adjustable system that can accommodate different operational requirements.
2Force
If a block is used to preload the torsion spring, then the seat back can be biased to the folded position, but the block must be precisely positioned to avoid friction and ensure smooth operation
Solution Approach 1:
The patent applies segmentation by dividing the preload adjustment into discrete, selectable blocks rather than using a continuous adjustment mechanism. Each block represents a discrete segment of possible preload values, allowing precise control of the spring force while simplifying the positioning requirement. The block is segmented into different thickness options that can be selected based on the specific application needs.
3Ease of operation
If the torsion spring is preloaded to bias the seat back, then folding is easier, but additional user force may be required to return the seat back to the upright position
Solution Approach 1:
The patent applies partial action by providing just enough preload through the selectable blocks to assist the folding motion, rather than over-preloading the spring. This ensures the spring provides sufficient bias to make folding easier while not creating excessive resistance during the return motion. The preload is calibrated to be partial - enough to help folding but not so much as to hinder return.
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
Enables the seat back to be easily folded forward without additional user force, as the torsion spring's preload adjusts based on selected trim packages and assembly variations, ensuring smooth operation and reduced friction during folding.
Implementation Method 1
A torsion spring with a first end region, a second opposed end region, and an intermediate region positioned therebetween
Data Source
AI summary
A vehicle seat assembly, a biasing mechanism, and a method of installing a vehicle seat assembly are provided. A first end region of a torsion spring is for fixed connection to a vehicle frame bracket mount such that the seat back rotates relative to the first end region of the spring about a transverse axis. A second end region of the torsion spring is offset from the transverse axis. A support bracket is connected to the seat back, with the intermediate region of the torsion spring supported for rotation by the support bracket. A block supported by the support bracket and offset from the transverse axis, with the block contacting the second end region of the torsion spring to bias the spring when the seat back is in a first, use position.