Vehicle Head Restraint Assembly with Spherical Bushing Guide
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Solution Overview
Problem
Existing adjustable head restraint systems for vehicles face issues with binding and misalignment due to tolerances and require multiple guide shafts, limiting positional flexibility and introducing complexity, weight, and noise.
Innovation Solution
A head restraint assembly featuring a single guide shaft with spherical bushings and a torsion spring mechanism that allows for infinitely adjustable fore and aft movement without binding, using a locking mechanism with levers and washers to eliminate the need for multiple guide shafts and reduce component complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If multiple guide shafts are used to support the head restraint, then stability and alignment are improved, but device complexity and weight increase
Solution Approach 1:
The single guide shaft is segmented into multiple sections with spherical bushings at each end, allowing each section to independently accommodate misalignment while maintaining overall stability. This segmentation enables the guide shaft to flex and adapt to tolerance variations without requiring multiple separate guide shafts.
Solution Approach 2:
Spherical bushings are introduced as intermediary elements between the guide shaft and the head restraint assembly. These bushings act as mediators that absorb misalignment and tolerance variations, allowing the single guide shaft to maintain stable alignment without requiring multiple rigid guide shafts.
2Reliability
If multiple guide shafts are used to eliminate binding, then reliability is improved, but weight and complexity increase
Solution Approach 1:
Spherical bushings with curved surfaces are used at each end of the guide shaft sections. This spheroidality allows for smooth rotational movement and accommodation of misalignment, eliminating binding conditions without requiring multiple heavy guide shafts. The spherical geometry provides continuous contact and smooth motion.
Solution Approach 2:
The guide shaft system changes from a rigid, straight configuration to a flexible, segmented configuration with spherical ends. This parameter change allows the guide shaft to adapt its shape and orientation to eliminate binding while maintaining reliability, reducing the need for multiple heavy guide shafts.
3Device complexity
If a single guide shaft is used to reduce complexity, then device complexity and weight are reduced, but positioning precision and smoothness deteriorate due to binding and misalignment
Solution Approach 1:
The guide shaft transitions from a static, rigid component to a dynamic, flexible component with spherical bushings that can rotate and adapt to misalignment. This dynamic capability allows the single guide shaft to maintain positioning precision and smooth operation despite manufacturing tolerances, eliminating binding conditions.
Solution Approach 2:
The spherical bushings are pre-configured to accommodate potential misalignment and tolerance variations before the head restraint is assembled and installed. This preliminary accommodation of misalignment ensures smooth operation and positioning precision from the start, eliminating the need for multiple guide shafts to compensate for these issues.
4Ease of manufacture
If traditional guide shafts without spherical bushings are used, then manufacturing is simpler, but binding and resistance occur due to misalignment
Solution Approach 1:
Spherical bushings with curved surfaces are added to the guide shaft ends, providing smooth rotational movement and accommodation of misalignment. This spheroidality eliminates binding conditions during adjustment while maintaining relatively simple manufacturing processes for the overall assembly.
Solution Approach 2:
Spherical bushings are introduced as intermediary elements between the guide shaft and mounting points. These bushings mediate the interaction between components, absorbing misalignment and preventing binding during adjustment, thereby improving operational smoothness without significantly complicating manufacturing.
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
The solution provides smooth, one-handed adjustment with reduced free-play and resistance, minimizing noise and weight while accommodating tolerances and misalignments, offering flexible and reliable head restraint positioning.
Implementation Method 1
The guide members may be connected by at least one spherical bushing which may accommodate misalignment and tolerances
Implementation Method 2
A torsion spring is connected to the first guide member and oriented about the second guide member for locking the second guide member relative to the first guide member
Data Source
AI summary
A head restraint assembly is provided with a first guide member mounted proximate to a vehicle seat back. A second guide member is mounted to the first guide member for translation along the first guide member. A locking mechanism is mounted to the second guide member in cooperation with the first guide member for locking the second guide member relative to the first guide member. The first and second guide members are connected by at least one spherical bushing. A torsion spring is connected to the first guide member and oriented about the second guide member for locking the second guide member relative to the first guide member.