Leaf Spring Bearing for Vehicle Headrest Height Adjustment
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Solution Overview
Problem
Existing vehicle seat assemblies experience undesirable noise, vibration, and sliding issues due to misalignment of head restraint posts within the mounting fixture, which affects the overall comfort and performance of the seat system.
Innovation Solution
The implementation of a head restraint assembly with bearings that include leaf springs and a low friction layer, which are designed to provide consistent sliding resistance and adjustability by engaging with the posts and guide sleeves, ensuring proper alignment and reducing frictional resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a traditional bearing is used to facilitate sliding of posts into the seat back, then sliding is enabled, but misalignment causes noise, vibration, and harshness
Solution Approach 1:
A compliant mounting fixture is introduced as an intermediary component between the head restraint posts and the seat back mounting fixture. This compliant fixture acts as a mediator that absorbs misalignment errors and prevents direct transmission of alignment errors to the bearing, thereby eliminating noise and vibration while maintaining smooth sliding operation.
Solution Approach 2:
The mounting fixture is designed with compliant characteristics that allow it to deform and adapt to misalignment conditions. By changing the mechanical properties of the mounting fixture from rigid to compliant, the system can accommodate alignment variations without generating harmful vibrations or noise.
2Adaptability or versatility
If the head restraint is made height adjustable, then adaptability is improved, but alignment maintenance becomes more difficult
Solution Approach 1:
The compliant mounting fixture serves as a buffer between the adjustable head restraint mechanism and the fixed seat back mounting points. As the head restraint moves to different height positions, the compliant fixture absorbs the alignment variations that occur during adjustment, maintaining proper bearing alignment throughout the range of motion.
Solution Approach 2:
The mounting fixture is designed to be dynamically compliant rather than statically rigid. This allows the fixture to adapt its configuration as the head restraint moves between different height positions, automatically maintaining proper alignment without requiring precision manufacturing at each discrete position.
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
This solution effectively reduces frictional resistance and eliminates or minimizes vibration and noise, allowing for smoother translation of the headrest relative to the seat back, enhancing the comfort and performance of the seat assembly while maintaining height adjustability.
Implementation Method 1
low friction layer overlying the substrate... reducing frictional resistance
Implementation Method 2
bearing may include a compliant mounting fixture... eliminate or substantially reduce vibration, or noise of the assembly
Data Source
AI summary
A head restraint assembly including a headrest including an inner member, a seat back including an outer member, and a bearing disposed between the inner member and the outer member, the bearing including at least one leaf spring adapted to bias the inner member, where the leaf spring includes a substrate and a low friction layer overlying the substrate, where the leaf spring includes an inner portion and a plurality of outer portions, where the outer portions include end portions of the leaf spring that are folded over such that the outer portions overlie the inner portion, forming a folded edge, where the headrest is adapted to translate with respect to the seat back, and where the seat back is adapted to receive the headrest such that the headrest is height adjustable relative to a seat back.