Active-Material Headrest Assembly for Adaptive Gap Reduction
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Solution Overview
Problem
Conventional headrest assemblies in vehicles face challenges in adjusting to varying occupant positions and sizes, leading to undesirable gaps between the headrest and the occupant's head, and require costly, power-hungry mechanical actuators that are not easily adaptable to different conditions.
Innovation Solution
The use of active material-based actuators, such as shape memory alloys and piezoelectric materials, that change stiffness and position in response to activation signals, allowing for morphable and tunable compliance of the headrest to reduce gaps and adapt to occupant needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional mechanical actuators are used to adjust headrest position, then the headrest can be positioned, but the device becomes costly and power-hungry
Solution Approach 1:
The patent replaces conventional mechanical actuators with active materials (piezoelectric materials, shape memory alloys, magnetorheological materials) that convert electrical, magnetic, or thermal energy directly into mechanical deformation or stiffness changes, eliminating the need for traditional motors and mechanical transmission systems
Solution Approach 2:
The invention changes the physical state or properties of active materials (such as piezoelectric polarization, shape memory phase transformation, magnetorheological viscosity) in response to external stimuli to achieve headrest positioning and compliance adjustment without mechanical actuators
2Ease of operation
If conventional mechanical actuators are used to adjust headrest position, then the headrest can be positioned, but the device complexity increases
Solution Approach 1:
The patent replaces complex mechanical actuator systems with integrated active material elements that are directly embedded in or attached to the headrest structure, converting multi-component mechanical systems into simpler electro-mechanical or magneto-mechanical systems
Solution Approach 2:
The invention merges the actuator function with the headrest structure itself by embedding active materials within the headrest body or attaching them to support posts, eliminating separate actuator assemblies and reducing overall system complexity
3Device complexity
If fixed headrest position is used, then the structure is simple, but the adaptability to different occupant positions is poor
Solution Approach 1:
The patent transforms the fixed headrest structure into a dynamic system where active materials can change the headrest position, orientation, or compliance in real-time based on detected occupant position, allowing the same simple structure to adapt to multiple configurations
Solution Approach 2:
The invention enables a single headrest structure to perform multiple functions (positioning, compliance adjustment, contouring) through active material actuation, making it universally adaptable to different occupant sizes, positions, and preferences without requiring multiple fixed configurations
4Manufacturing precision
If active material actuators are used to reduce headrest gap, then the gap reduction is effective, but the mechanism complexity increases
Solution Approach 1:
The patent replaces complex mechanical positioning mechanisms with active material actuators that directly deform or move headrest components in response to electrical or magnetic signals, achieving precise gap control without mechanical linkages
Solution Approach 2:
The invention applies active material actuators at specific locations within the headrest structure (such as near the contact surface or at pivot points) to achieve localized gap reduction and compliance adjustment, rather than requiring system-wide mechanical adjustments
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 provides a robust, low-power, and noise-free mechanism for dynamically adjusting the headrest's position and stiffness, effectively reducing gaps and improving comfort and protection across various occupant sizes and conditions.
Implementation Method 1
active material based actuators, such as shape memory alloys
Implementation Method 2
active material based actuators, such as shape memory alloys and piezoelectric materials
Data Source
AI summary
A headrest assembly for a seat includes a body portion having at least one padded surface positioned in substantial alignment with a seated occupant's head; and an active material in operative communication with the at least one padded surface of the body portion, the active material being operative to change at least one attribute in response to an activation signal, wherein a space between the occupant's head and the at least one padded surface decreases with the change in the at least one attribute of the active material.